1 /*
2  *  linux/mm/page_alloc.c
3  *
4  *  Manages the free list, the system allocates free pages here.
5  *  Note that kmalloc() lives in slab.c
6  *
7  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
8  *  Swap reorganised 29.12.95, Stephen Tweedie
9  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
10  *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
11  *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
12  *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
13  *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
14  *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
15  */
16 
17 #include <linux/stddef.h>
18 #include <linux/mm.h>
19 #include <linux/swap.h>
20 #include <linux/interrupt.h>
21 #include <linux/pagemap.h>
22 #include <linux/jiffies.h>
23 #include <linux/bootmem.h>
24 #include <linux/memblock.h>
25 #include <linux/compiler.h>
26 #include <linux/kernel.h>
27 #include <linux/kmemcheck.h>
28 #include <linux/module.h>
29 #include <linux/suspend.h>
30 #include <linux/pagevec.h>
31 #include <linux/blkdev.h>
32 #include <linux/slab.h>
33 #include <linux/oom.h>
34 #include <linux/notifier.h>
35 #include <linux/topology.h>
36 #include <linux/sysctl.h>
37 #include <linux/cpu.h>
38 #include <linux/cpuset.h>
39 #include <linux/memory_hotplug.h>
40 #include <linux/nodemask.h>
41 #include <linux/vmalloc.h>
42 #include <linux/mempolicy.h>
43 #include <linux/stop_machine.h>
44 #include <linux/sort.h>
45 #include <linux/pfn.h>
46 #include <linux/backing-dev.h>
47 #include <linux/fault-inject.h>
48 #include <linux/page-isolation.h>
49 #include <linux/page_cgroup.h>
50 #include <linux/debugobjects.h>
51 #include <linux/kmemleak.h>
52 #include <linux/memory.h>
53 #include <linux/compaction.h>
54 #include <trace/events/kmem.h>
55 #include <linux/ftrace_event.h>
56 #include <linux/memcontrol.h>
57 
58 #include <asm/tlbflush.h>
59 #include <asm/div64.h>
60 #include "internal.h"
61 
62 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
63 DEFINE_PER_CPU(int, numa_node);
64 EXPORT_PER_CPU_SYMBOL(numa_node);
65 #endif
66 
67 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
68 /*
69  * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
70  * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
71  * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
72  * defined in <linux/topology.h>.
73  */
74 DEFINE_PER_CPU(int, _numa_mem_);		/* Kernel "local memory" node */
75 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
76 #endif
77 
78 /*
79  * Array of node states.
80  */
81 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
82 	[N_POSSIBLE] = NODE_MASK_ALL,
83 	[N_ONLINE] = { { [0] = 1UL } },
84 #ifndef CONFIG_NUMA
85 	[N_NORMAL_MEMORY] = { { [0] = 1UL } },
86 #ifdef CONFIG_HIGHMEM
87 	[N_HIGH_MEMORY] = { { [0] = 1UL } },
88 #endif
89 	[N_CPU] = { { [0] = 1UL } },
90 #endif	/* NUMA */
91 };
92 EXPORT_SYMBOL(node_states);
93 
94 unsigned long totalram_pages __read_mostly;
95 unsigned long totalreserve_pages __read_mostly;
96 int percpu_pagelist_fraction;
97 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
98 
99 #ifdef CONFIG_PM_SLEEP
100 /*
101  * The following functions are used by the suspend/hibernate code to temporarily
102  * change gfp_allowed_mask in order to avoid using I/O during memory allocations
103  * while devices are suspended.  To avoid races with the suspend/hibernate code,
104  * they should always be called with pm_mutex held (gfp_allowed_mask also should
105  * only be modified with pm_mutex held, unless the suspend/hibernate code is
106  * guaranteed not to run in parallel with that modification).
107  */
108 
109 static gfp_t saved_gfp_mask;
110 
pm_restore_gfp_mask(void)111 void pm_restore_gfp_mask(void)
112 {
113 	WARN_ON(!mutex_is_locked(&pm_mutex));
114 	if (saved_gfp_mask) {
115 		gfp_allowed_mask = saved_gfp_mask;
116 		saved_gfp_mask = 0;
117 	}
118 }
119 
pm_restrict_gfp_mask(void)120 void pm_restrict_gfp_mask(void)
121 {
122 	WARN_ON(!mutex_is_locked(&pm_mutex));
123 	WARN_ON(saved_gfp_mask);
124 	saved_gfp_mask = gfp_allowed_mask;
125 	gfp_allowed_mask &= ~GFP_IOFS;
126 }
127 #endif /* CONFIG_PM_SLEEP */
128 
129 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
130 int pageblock_order __read_mostly;
131 #endif
132 
133 static void __free_pages_ok(struct page *page, unsigned int order);
134 
135 /*
136  * results with 256, 32 in the lowmem_reserve sysctl:
137  *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
138  *	1G machine -> (16M dma, 784M normal, 224M high)
139  *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
140  *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
141  *	HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
142  *
143  * TBD: should special case ZONE_DMA32 machines here - in those we normally
144  * don't need any ZONE_NORMAL reservation
145  */
146 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
147 #ifdef CONFIG_ZONE_DMA
148 	 256,
149 #endif
150 #ifdef CONFIG_ZONE_DMA32
151 	 256,
152 #endif
153 #ifdef CONFIG_HIGHMEM
154 	 32,
155 #endif
156 	 32,
157 };
158 
159 EXPORT_SYMBOL(totalram_pages);
160 
161 static char * const zone_names[MAX_NR_ZONES] = {
162 #ifdef CONFIG_ZONE_DMA
163 	 "DMA",
164 #endif
165 #ifdef CONFIG_ZONE_DMA32
166 	 "DMA32",
167 #endif
168 	 "Normal",
169 #ifdef CONFIG_HIGHMEM
170 	 "HighMem",
171 #endif
172 	 "Movable",
173 };
174 
175 int min_free_kbytes = 1024;
176 
177 static unsigned long __meminitdata nr_kernel_pages;
178 static unsigned long __meminitdata nr_all_pages;
179 static unsigned long __meminitdata dma_reserve;
180 
181 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
182   /*
183    * MAX_ACTIVE_REGIONS determines the maximum number of distinct
184    * ranges of memory (RAM) that may be registered with add_active_range().
185    * Ranges passed to add_active_range() will be merged if possible
186    * so the number of times add_active_range() can be called is
187    * related to the number of nodes and the number of holes
188    */
189   #ifdef CONFIG_MAX_ACTIVE_REGIONS
190     /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
191     #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
192   #else
193     #if MAX_NUMNODES >= 32
194       /* If there can be many nodes, allow up to 50 holes per node */
195       #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
196     #else
197       /* By default, allow up to 256 distinct regions */
198       #define MAX_ACTIVE_REGIONS 256
199     #endif
200   #endif
201 
202   static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
203   static int __meminitdata nr_nodemap_entries;
204   static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
205   static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
206   static unsigned long __initdata required_kernelcore;
207   static unsigned long __initdata required_movablecore;
208   static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
209 
210   /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
211   int movable_zone;
212   EXPORT_SYMBOL(movable_zone);
213 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
214 
215 #if MAX_NUMNODES > 1
216 int nr_node_ids __read_mostly = MAX_NUMNODES;
217 int nr_online_nodes __read_mostly = 1;
218 EXPORT_SYMBOL(nr_node_ids);
219 EXPORT_SYMBOL(nr_online_nodes);
220 #endif
221 
222 int page_group_by_mobility_disabled __read_mostly;
223 
set_pageblock_migratetype(struct page * page,int migratetype)224 static void set_pageblock_migratetype(struct page *page, int migratetype)
225 {
226 
227 	if (unlikely(page_group_by_mobility_disabled))
228 		migratetype = MIGRATE_UNMOVABLE;
229 
230 	set_pageblock_flags_group(page, (unsigned long)migratetype,
231 					PB_migrate, PB_migrate_end);
232 }
233 
234 bool oom_killer_disabled __read_mostly;
235 
236 #ifdef CONFIG_DEBUG_VM
page_outside_zone_boundaries(struct zone * zone,struct page * page)237 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
238 {
239 	int ret = 0;
240 	unsigned seq;
241 	unsigned long pfn = page_to_pfn(page);
242 
243 	do {
244 		seq = zone_span_seqbegin(zone);
245 		if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
246 			ret = 1;
247 		else if (pfn < zone->zone_start_pfn)
248 			ret = 1;
249 	} while (zone_span_seqretry(zone, seq));
250 
251 	return ret;
252 }
253 
page_is_consistent(struct zone * zone,struct page * page)254 static int page_is_consistent(struct zone *zone, struct page *page)
255 {
256 	if (!pfn_valid_within(page_to_pfn(page)))
257 		return 0;
258 	if (zone != page_zone(page))
259 		return 0;
260 
261 	return 1;
262 }
263 /*
264  * Temporary debugging check for pages not lying within a given zone.
265  */
bad_range(struct zone * zone,struct page * page)266 static int bad_range(struct zone *zone, struct page *page)
267 {
268 	if (page_outside_zone_boundaries(zone, page))
269 		return 1;
270 	if (!page_is_consistent(zone, page))
271 		return 1;
272 
273 	return 0;
274 }
275 #else
bad_range(struct zone * zone,struct page * page)276 static inline int bad_range(struct zone *zone, struct page *page)
277 {
278 	return 0;
279 }
280 #endif
281 
bad_page(struct page * page)282 static void bad_page(struct page *page)
283 {
284 	static unsigned long resume;
285 	static unsigned long nr_shown;
286 	static unsigned long nr_unshown;
287 
288 	/* Don't complain about poisoned pages */
289 	if (PageHWPoison(page)) {
290 		reset_page_mapcount(page); /* remove PageBuddy */
291 		return;
292 	}
293 
294 	/*
295 	 * Allow a burst of 60 reports, then keep quiet for that minute;
296 	 * or allow a steady drip of one report per second.
297 	 */
298 	if (nr_shown == 60) {
299 		if (time_before(jiffies, resume)) {
300 			nr_unshown++;
301 			goto out;
302 		}
303 		if (nr_unshown) {
304 			printk(KERN_ALERT
305 			      "BUG: Bad page state: %lu messages suppressed\n",
306 				nr_unshown);
307 			nr_unshown = 0;
308 		}
309 		nr_shown = 0;
310 	}
311 	if (nr_shown++ == 0)
312 		resume = jiffies + 60 * HZ;
313 
314 	printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",
315 		current->comm, page_to_pfn(page));
316 	dump_page(page);
317 
318 	dump_stack();
319 out:
320 	/* Leave bad fields for debug, except PageBuddy could make trouble */
321 	reset_page_mapcount(page); /* remove PageBuddy */
322 	add_taint(TAINT_BAD_PAGE);
323 }
324 
325 /*
326  * Higher-order pages are called "compound pages".  They are structured thusly:
327  *
328  * The first PAGE_SIZE page is called the "head page".
329  *
330  * The remaining PAGE_SIZE pages are called "tail pages".
331  *
332  * All pages have PG_compound set.  All pages have their ->private pointing at
333  * the head page (even the head page has this).
334  *
335  * The first tail page's ->lru.next holds the address of the compound page's
336  * put_page() function.  Its ->lru.prev holds the order of allocation.
337  * This usage means that zero-order pages may not be compound.
338  */
339 
free_compound_page(struct page * page)340 static void free_compound_page(struct page *page)
341 {
342 	__free_pages_ok(page, compound_order(page));
343 }
344 
prep_compound_page(struct page * page,unsigned long order)345 void prep_compound_page(struct page *page, unsigned long order)
346 {
347 	int i;
348 	int nr_pages = 1 << order;
349 
350 	set_compound_page_dtor(page, free_compound_page);
351 	set_compound_order(page, order);
352 	__SetPageHead(page);
353 	for (i = 1; i < nr_pages; i++) {
354 		struct page *p = page + i;
355 
356 		__SetPageTail(p);
357 		p->first_page = page;
358 	}
359 }
360 
361 /* update __split_huge_page_refcount if you change this function */
destroy_compound_page(struct page * page,unsigned long order)362 static int destroy_compound_page(struct page *page, unsigned long order)
363 {
364 	int i;
365 	int nr_pages = 1 << order;
366 	int bad = 0;
367 
368 	if (unlikely(compound_order(page) != order) ||
369 	    unlikely(!PageHead(page))) {
370 		bad_page(page);
371 		bad++;
372 	}
373 
374 	__ClearPageHead(page);
375 
376 	for (i = 1; i < nr_pages; i++) {
377 		struct page *p = page + i;
378 
379 		if (unlikely(!PageTail(p) || (p->first_page != page))) {
380 			bad_page(page);
381 			bad++;
382 		}
383 		__ClearPageTail(p);
384 	}
385 
386 	return bad;
387 }
388 
prep_zero_page(struct page * page,int order,gfp_t gfp_flags)389 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
390 {
391 	int i;
392 
393 	/*
394 	 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
395 	 * and __GFP_HIGHMEM from hard or soft interrupt context.
396 	 */
397 	VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
398 	for (i = 0; i < (1 << order); i++)
399 		clear_highpage(page + i);
400 }
401 
set_page_order(struct page * page,int order)402 static inline void set_page_order(struct page *page, int order)
403 {
404 	set_page_private(page, order);
405 	__SetPageBuddy(page);
406 }
407 
rmv_page_order(struct page * page)408 static inline void rmv_page_order(struct page *page)
409 {
410 	__ClearPageBuddy(page);
411 	set_page_private(page, 0);
412 }
413 
414 /*
415  * Locate the struct page for both the matching buddy in our
416  * pair (buddy1) and the combined O(n+1) page they form (page).
417  *
418  * 1) Any buddy B1 will have an order O twin B2 which satisfies
419  * the following equation:
420  *     B2 = B1 ^ (1 << O)
421  * For example, if the starting buddy (buddy2) is #8 its order
422  * 1 buddy is #10:
423  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
424  *
425  * 2) Any buddy B will have an order O+1 parent P which
426  * satisfies the following equation:
427  *     P = B & ~(1 << O)
428  *
429  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
430  */
431 static inline unsigned long
__find_buddy_index(unsigned long page_idx,unsigned int order)432 __find_buddy_index(unsigned long page_idx, unsigned int order)
433 {
434 	return page_idx ^ (1 << order);
435 }
436 
437 /*
438  * This function checks whether a page is free && is the buddy
439  * we can do coalesce a page and its buddy if
440  * (a) the buddy is not in a hole &&
441  * (b) the buddy is in the buddy system &&
442  * (c) a page and its buddy have the same order &&
443  * (d) a page and its buddy are in the same zone.
444  *
445  * For recording whether a page is in the buddy system, we set ->_mapcount -2.
446  * Setting, clearing, and testing _mapcount -2 is serialized by zone->lock.
447  *
448  * For recording page's order, we use page_private(page).
449  */
page_is_buddy(struct page * page,struct page * buddy,int order)450 static inline int page_is_buddy(struct page *page, struct page *buddy,
451 								int order)
452 {
453 	if (!pfn_valid_within(page_to_pfn(buddy)))
454 		return 0;
455 
456 	if (page_zone_id(page) != page_zone_id(buddy))
457 		return 0;
458 
459 	if (PageBuddy(buddy) && page_order(buddy) == order) {
460 		VM_BUG_ON(page_count(buddy) != 0);
461 		return 1;
462 	}
463 	return 0;
464 }
465 
466 /*
467  * Freeing function for a buddy system allocator.
468  *
469  * The concept of a buddy system is to maintain direct-mapped table
470  * (containing bit values) for memory blocks of various "orders".
471  * The bottom level table contains the map for the smallest allocatable
472  * units of memory (here, pages), and each level above it describes
473  * pairs of units from the levels below, hence, "buddies".
474  * At a high level, all that happens here is marking the table entry
475  * at the bottom level available, and propagating the changes upward
476  * as necessary, plus some accounting needed to play nicely with other
477  * parts of the VM system.
478  * At each level, we keep a list of pages, which are heads of continuous
479  * free pages of length of (1 << order) and marked with _mapcount -2. Page's
480  * order is recorded in page_private(page) field.
481  * So when we are allocating or freeing one, we can derive the state of the
482  * other.  That is, if we allocate a small block, and both were
483  * free, the remainder of the region must be split into blocks.
484  * If a block is freed, and its buddy is also free, then this
485  * triggers coalescing into a block of larger size.
486  *
487  * -- wli
488  */
489 
__free_one_page(struct page * page,struct zone * zone,unsigned int order,int migratetype)490 static inline void __free_one_page(struct page *page,
491 		struct zone *zone, unsigned int order,
492 		int migratetype)
493 {
494 	unsigned long page_idx;
495 	unsigned long combined_idx;
496 	unsigned long uninitialized_var(buddy_idx);
497 	struct page *buddy;
498 
499 	if (unlikely(PageCompound(page)))
500 		if (unlikely(destroy_compound_page(page, order)))
501 			return;
502 
503 	VM_BUG_ON(migratetype == -1);
504 
505 	page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
506 
507 	VM_BUG_ON(page_idx & ((1 << order) - 1));
508 	VM_BUG_ON(bad_range(zone, page));
509 
510 	while (order < MAX_ORDER-1) {
511 		buddy_idx = __find_buddy_index(page_idx, order);
512 		buddy = page + (buddy_idx - page_idx);
513 		if (!page_is_buddy(page, buddy, order))
514 			break;
515 
516 		/* Our buddy is free, merge with it and move up one order. */
517 		list_del(&buddy->lru);
518 		zone->free_area[order].nr_free--;
519 		rmv_page_order(buddy);
520 		combined_idx = buddy_idx & page_idx;
521 		page = page + (combined_idx - page_idx);
522 		page_idx = combined_idx;
523 		order++;
524 	}
525 	set_page_order(page, order);
526 
527 	/*
528 	 * If this is not the largest possible page, check if the buddy
529 	 * of the next-highest order is free. If it is, it's possible
530 	 * that pages are being freed that will coalesce soon. In case,
531 	 * that is happening, add the free page to the tail of the list
532 	 * so it's less likely to be used soon and more likely to be merged
533 	 * as a higher order page
534 	 */
535 	if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
536 		struct page *higher_page, *higher_buddy;
537 		combined_idx = buddy_idx & page_idx;
538 		higher_page = page + (combined_idx - page_idx);
539 		buddy_idx = __find_buddy_index(combined_idx, order + 1);
540 		higher_buddy = page + (buddy_idx - combined_idx);
541 		if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
542 			list_add_tail(&page->lru,
543 				&zone->free_area[order].free_list[migratetype]);
544 			goto out;
545 		}
546 	}
547 
548 	list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
549 out:
550 	zone->free_area[order].nr_free++;
551 }
552 
553 /*
554  * free_page_mlock() -- clean up attempts to free and mlocked() page.
555  * Page should not be on lru, so no need to fix that up.
556  * free_pages_check() will verify...
557  */
free_page_mlock(struct page * page)558 static inline void free_page_mlock(struct page *page)
559 {
560 	__dec_zone_page_state(page, NR_MLOCK);
561 	__count_vm_event(UNEVICTABLE_MLOCKFREED);
562 }
563 
free_pages_check(struct page * page)564 static inline int free_pages_check(struct page *page)
565 {
566 	if (unlikely(page_mapcount(page) |
567 		(page->mapping != NULL)  |
568 		(atomic_read(&page->_count) != 0) |
569 		(page->flags & PAGE_FLAGS_CHECK_AT_FREE) |
570 		(mem_cgroup_bad_page_check(page)))) {
571 		bad_page(page);
572 		return 1;
573 	}
574 	if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
575 		page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
576 	return 0;
577 }
578 
579 /*
580  * Frees a number of pages from the PCP lists
581  * Assumes all pages on list are in same zone, and of same order.
582  * count is the number of pages to free.
583  *
584  * If the zone was previously in an "all pages pinned" state then look to
585  * see if this freeing clears that state.
586  *
587  * And clear the zone's pages_scanned counter, to hold off the "all pages are
588  * pinned" detection logic.
589  */
free_pcppages_bulk(struct zone * zone,int count,struct per_cpu_pages * pcp)590 static void free_pcppages_bulk(struct zone *zone, int count,
591 					struct per_cpu_pages *pcp)
592 {
593 	int migratetype = 0;
594 	int batch_free = 0;
595 	int to_free = count;
596 
597 	spin_lock(&zone->lock);
598 	zone->all_unreclaimable = 0;
599 	zone->pages_scanned = 0;
600 
601 	while (to_free) {
602 		struct page *page;
603 		struct list_head *list;
604 
605 		/*
606 		 * Remove pages from lists in a round-robin fashion. A
607 		 * batch_free count is maintained that is incremented when an
608 		 * empty list is encountered.  This is so more pages are freed
609 		 * off fuller lists instead of spinning excessively around empty
610 		 * lists
611 		 */
612 		do {
613 			batch_free++;
614 			if (++migratetype == MIGRATE_PCPTYPES)
615 				migratetype = 0;
616 			list = &pcp->lists[migratetype];
617 		} while (list_empty(list));
618 
619 		/* This is the only non-empty list. Free them all. */
620 		if (batch_free == MIGRATE_PCPTYPES)
621 			batch_free = to_free;
622 
623 		do {
624 			page = list_entry(list->prev, struct page, lru);
625 			/* must delete as __free_one_page list manipulates */
626 			list_del(&page->lru);
627 			/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
628 			__free_one_page(page, zone, 0, page_private(page));
629 			trace_mm_page_pcpu_drain(page, 0, page_private(page));
630 		} while (--to_free && --batch_free && !list_empty(list));
631 	}
632 	__mod_zone_page_state(zone, NR_FREE_PAGES, count);
633 	spin_unlock(&zone->lock);
634 }
635 
free_one_page(struct zone * zone,struct page * page,int order,int migratetype)636 static void free_one_page(struct zone *zone, struct page *page, int order,
637 				int migratetype)
638 {
639 	spin_lock(&zone->lock);
640 	zone->all_unreclaimable = 0;
641 	zone->pages_scanned = 0;
642 
643 	__free_one_page(page, zone, order, migratetype);
644 	__mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
645 	spin_unlock(&zone->lock);
646 }
647 
free_pages_prepare(struct page * page,unsigned int order)648 static bool free_pages_prepare(struct page *page, unsigned int order)
649 {
650 	int i;
651 	int bad = 0;
652 
653 	trace_mm_page_free_direct(page, order);
654 	kmemcheck_free_shadow(page, order);
655 
656 	if (PageAnon(page))
657 		page->mapping = NULL;
658 	for (i = 0; i < (1 << order); i++)
659 		bad += free_pages_check(page + i);
660 	if (bad)
661 		return false;
662 
663 	if (!PageHighMem(page)) {
664 		debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
665 		debug_check_no_obj_freed(page_address(page),
666 					   PAGE_SIZE << order);
667 	}
668 	arch_free_page(page, order);
669 	kernel_map_pages(page, 1 << order, 0);
670 
671 	return true;
672 }
673 
__free_pages_ok(struct page * page,unsigned int order)674 static void __free_pages_ok(struct page *page, unsigned int order)
675 {
676 	unsigned long flags;
677 	int wasMlocked = __TestClearPageMlocked(page);
678 
679 	if (!free_pages_prepare(page, order))
680 		return;
681 
682 	local_irq_save(flags);
683 	if (unlikely(wasMlocked))
684 		free_page_mlock(page);
685 	__count_vm_events(PGFREE, 1 << order);
686 	free_one_page(page_zone(page), page, order,
687 					get_pageblock_migratetype(page));
688 	local_irq_restore(flags);
689 }
690 
691 /*
692  * permit the bootmem allocator to evade page validation on high-order frees
693  */
__free_pages_bootmem(struct page * page,unsigned int order)694 void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
695 {
696 	if (order == 0) {
697 		__ClearPageReserved(page);
698 		set_page_count(page, 0);
699 		set_page_refcounted(page);
700 		__free_page(page);
701 	} else {
702 		int loop;
703 
704 		prefetchw(page);
705 		for (loop = 0; loop < BITS_PER_LONG; loop++) {
706 			struct page *p = &page[loop];
707 
708 			if (loop + 1 < BITS_PER_LONG)
709 				prefetchw(p + 1);
710 			__ClearPageReserved(p);
711 			set_page_count(p, 0);
712 		}
713 
714 		set_page_refcounted(page);
715 		__free_pages(page, order);
716 	}
717 }
718 
719 
720 /*
721  * The order of subdivision here is critical for the IO subsystem.
722  * Please do not alter this order without good reasons and regression
723  * testing. Specifically, as large blocks of memory are subdivided,
724  * the order in which smaller blocks are delivered depends on the order
725  * they're subdivided in this function. This is the primary factor
726  * influencing the order in which pages are delivered to the IO
727  * subsystem according to empirical testing, and this is also justified
728  * by considering the behavior of a buddy system containing a single
729  * large block of memory acted on by a series of small allocations.
730  * This behavior is a critical factor in sglist merging's success.
731  *
732  * -- wli
733  */
expand(struct zone * zone,struct page * page,int low,int high,struct free_area * area,int migratetype)734 static inline void expand(struct zone *zone, struct page *page,
735 	int low, int high, struct free_area *area,
736 	int migratetype)
737 {
738 	unsigned long size = 1 << high;
739 
740 	while (high > low) {
741 		area--;
742 		high--;
743 		size >>= 1;
744 		VM_BUG_ON(bad_range(zone, &page[size]));
745 		list_add(&page[size].lru, &area->free_list[migratetype]);
746 		area->nr_free++;
747 		set_page_order(&page[size], high);
748 	}
749 }
750 
751 /*
752  * This page is about to be returned from the page allocator
753  */
check_new_page(struct page * page)754 static inline int check_new_page(struct page *page)
755 {
756 	if (unlikely(page_mapcount(page) |
757 		(page->mapping != NULL)  |
758 		(atomic_read(&page->_count) != 0)  |
759 		(page->flags & PAGE_FLAGS_CHECK_AT_PREP) |
760 		(mem_cgroup_bad_page_check(page)))) {
761 		bad_page(page);
762 		return 1;
763 	}
764 	return 0;
765 }
766 
prep_new_page(struct page * page,int order,gfp_t gfp_flags)767 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
768 {
769 	int i;
770 
771 	for (i = 0; i < (1 << order); i++) {
772 		struct page *p = page + i;
773 		if (unlikely(check_new_page(p)))
774 			return 1;
775 	}
776 
777 	set_page_private(page, 0);
778 	set_page_refcounted(page);
779 
780 	arch_alloc_page(page, order);
781 	kernel_map_pages(page, 1 << order, 1);
782 
783 	if (gfp_flags & __GFP_ZERO)
784 		prep_zero_page(page, order, gfp_flags);
785 
786 	if (order && (gfp_flags & __GFP_COMP))
787 		prep_compound_page(page, order);
788 
789 	return 0;
790 }
791 
792 /*
793  * Go through the free lists for the given migratetype and remove
794  * the smallest available page from the freelists
795  */
796 static inline
__rmqueue_smallest(struct zone * zone,unsigned int order,int migratetype)797 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
798 						int migratetype)
799 {
800 	unsigned int current_order;
801 	struct free_area * area;
802 	struct page *page;
803 
804 	/* Find a page of the appropriate size in the preferred list */
805 	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
806 		area = &(zone->free_area[current_order]);
807 		if (list_empty(&area->free_list[migratetype]))
808 			continue;
809 
810 		page = list_entry(area->free_list[migratetype].next,
811 							struct page, lru);
812 		list_del(&page->lru);
813 		rmv_page_order(page);
814 		area->nr_free--;
815 		expand(zone, page, order, current_order, area, migratetype);
816 		return page;
817 	}
818 
819 	return NULL;
820 }
821 
822 
823 /*
824  * This array describes the order lists are fallen back to when
825  * the free lists for the desirable migrate type are depleted
826  */
827 static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
828 	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
829 	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
830 	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
831 	[MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE }, /* Never used */
832 };
833 
834 /*
835  * Move the free pages in a range to the free lists of the requested type.
836  * Note that start_page and end_pages are not aligned on a pageblock
837  * boundary. If alignment is required, use move_freepages_block()
838  */
move_freepages(struct zone * zone,struct page * start_page,struct page * end_page,int migratetype)839 static int move_freepages(struct zone *zone,
840 			  struct page *start_page, struct page *end_page,
841 			  int migratetype)
842 {
843 	struct page *page;
844 	unsigned long order;
845 	int pages_moved = 0;
846 
847 #ifndef CONFIG_HOLES_IN_ZONE
848 	/*
849 	 * page_zone is not safe to call in this context when
850 	 * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
851 	 * anyway as we check zone boundaries in move_freepages_block().
852 	 * Remove at a later date when no bug reports exist related to
853 	 * grouping pages by mobility
854 	 */
855 	BUG_ON(page_zone(start_page) != page_zone(end_page));
856 #endif
857 
858 	for (page = start_page; page <= end_page;) {
859 		/* Make sure we are not inadvertently changing nodes */
860 		VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
861 
862 		if (!pfn_valid_within(page_to_pfn(page))) {
863 			page++;
864 			continue;
865 		}
866 
867 		if (!PageBuddy(page)) {
868 			page++;
869 			continue;
870 		}
871 
872 		order = page_order(page);
873 		list_move(&page->lru,
874 			  &zone->free_area[order].free_list[migratetype]);
875 		page += 1 << order;
876 		pages_moved += 1 << order;
877 	}
878 
879 	return pages_moved;
880 }
881 
move_freepages_block(struct zone * zone,struct page * page,int migratetype)882 static int move_freepages_block(struct zone *zone, struct page *page,
883 				int migratetype)
884 {
885 	unsigned long start_pfn, end_pfn;
886 	struct page *start_page, *end_page;
887 
888 	start_pfn = page_to_pfn(page);
889 	start_pfn = start_pfn & ~(pageblock_nr_pages-1);
890 	start_page = pfn_to_page(start_pfn);
891 	end_page = start_page + pageblock_nr_pages - 1;
892 	end_pfn = start_pfn + pageblock_nr_pages - 1;
893 
894 	/* Do not cross zone boundaries */
895 	if (start_pfn < zone->zone_start_pfn)
896 		start_page = page;
897 	if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
898 		return 0;
899 
900 	return move_freepages(zone, start_page, end_page, migratetype);
901 }
902 
change_pageblock_range(struct page * pageblock_page,int start_order,int migratetype)903 static void change_pageblock_range(struct page *pageblock_page,
904 					int start_order, int migratetype)
905 {
906 	int nr_pageblocks = 1 << (start_order - pageblock_order);
907 
908 	while (nr_pageblocks--) {
909 		set_pageblock_migratetype(pageblock_page, migratetype);
910 		pageblock_page += pageblock_nr_pages;
911 	}
912 }
913 
914 /* Remove an element from the buddy allocator from the fallback list */
915 static inline struct page *
__rmqueue_fallback(struct zone * zone,int order,int start_migratetype)916 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
917 {
918 	struct free_area * area;
919 	int current_order;
920 	struct page *page;
921 	int migratetype, i;
922 
923 	/* Find the largest possible block of pages in the other list */
924 	for (current_order = MAX_ORDER-1; current_order >= order;
925 						--current_order) {
926 		for (i = 0; i < MIGRATE_TYPES - 1; i++) {
927 			migratetype = fallbacks[start_migratetype][i];
928 
929 			/* MIGRATE_RESERVE handled later if necessary */
930 			if (migratetype == MIGRATE_RESERVE)
931 				continue;
932 
933 			area = &(zone->free_area[current_order]);
934 			if (list_empty(&area->free_list[migratetype]))
935 				continue;
936 
937 			page = list_entry(area->free_list[migratetype].next,
938 					struct page, lru);
939 			area->nr_free--;
940 
941 			/*
942 			 * If breaking a large block of pages, move all free
943 			 * pages to the preferred allocation list. If falling
944 			 * back for a reclaimable kernel allocation, be more
945 			 * aggressive about taking ownership of free pages
946 			 */
947 			if (unlikely(current_order >= (pageblock_order >> 1)) ||
948 					start_migratetype == MIGRATE_RECLAIMABLE ||
949 					page_group_by_mobility_disabled) {
950 				unsigned long pages;
951 				pages = move_freepages_block(zone, page,
952 								start_migratetype);
953 
954 				/* Claim the whole block if over half of it is free */
955 				if (pages >= (1 << (pageblock_order-1)) ||
956 						page_group_by_mobility_disabled)
957 					set_pageblock_migratetype(page,
958 								start_migratetype);
959 
960 				migratetype = start_migratetype;
961 			}
962 
963 			/* Remove the page from the freelists */
964 			list_del(&page->lru);
965 			rmv_page_order(page);
966 
967 			/* Take ownership for orders >= pageblock_order */
968 			if (current_order >= pageblock_order)
969 				change_pageblock_range(page, current_order,
970 							start_migratetype);
971 
972 			expand(zone, page, order, current_order, area, migratetype);
973 
974 			trace_mm_page_alloc_extfrag(page, order, current_order,
975 				start_migratetype, migratetype);
976 
977 			return page;
978 		}
979 	}
980 
981 	return NULL;
982 }
983 
984 /*
985  * Do the hard work of removing an element from the buddy allocator.
986  * Call me with the zone->lock already held.
987  */
__rmqueue(struct zone * zone,unsigned int order,int migratetype)988 static struct page *__rmqueue(struct zone *zone, unsigned int order,
989 						int migratetype)
990 {
991 	struct page *page;
992 
993 retry_reserve:
994 	page = __rmqueue_smallest(zone, order, migratetype);
995 
996 	if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
997 		page = __rmqueue_fallback(zone, order, migratetype);
998 
999 		/*
1000 		 * Use MIGRATE_RESERVE rather than fail an allocation. goto
1001 		 * is used because __rmqueue_smallest is an inline function
1002 		 * and we want just one call site
1003 		 */
1004 		if (!page) {
1005 			migratetype = MIGRATE_RESERVE;
1006 			goto retry_reserve;
1007 		}
1008 	}
1009 
1010 	trace_mm_page_alloc_zone_locked(page, order, migratetype);
1011 	return page;
1012 }
1013 
1014 /*
1015  * Obtain a specified number of elements from the buddy allocator, all under
1016  * a single hold of the lock, for efficiency.  Add them to the supplied list.
1017  * Returns the number of new pages which were placed at *list.
1018  */
rmqueue_bulk(struct zone * zone,unsigned int order,unsigned long count,struct list_head * list,int migratetype,int cold)1019 static int rmqueue_bulk(struct zone *zone, unsigned int order,
1020 			unsigned long count, struct list_head *list,
1021 			int migratetype, int cold)
1022 {
1023 	int i;
1024 
1025 	spin_lock(&zone->lock);
1026 	for (i = 0; i < count; ++i) {
1027 		struct page *page = __rmqueue(zone, order, migratetype);
1028 		if (unlikely(page == NULL))
1029 			break;
1030 
1031 		/*
1032 		 * Split buddy pages returned by expand() are received here
1033 		 * in physical page order. The page is added to the callers and
1034 		 * list and the list head then moves forward. From the callers
1035 		 * perspective, the linked list is ordered by page number in
1036 		 * some conditions. This is useful for IO devices that can
1037 		 * merge IO requests if the physical pages are ordered
1038 		 * properly.
1039 		 */
1040 		if (likely(cold == 0))
1041 			list_add(&page->lru, list);
1042 		else
1043 			list_add_tail(&page->lru, list);
1044 		set_page_private(page, migratetype);
1045 		list = &page->lru;
1046 	}
1047 	__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1048 	spin_unlock(&zone->lock);
1049 	return i;
1050 }
1051 
1052 #ifdef CONFIG_NUMA
1053 /*
1054  * Called from the vmstat counter updater to drain pagesets of this
1055  * currently executing processor on remote nodes after they have
1056  * expired.
1057  *
1058  * Note that this function must be called with the thread pinned to
1059  * a single processor.
1060  */
drain_zone_pages(struct zone * zone,struct per_cpu_pages * pcp)1061 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1062 {
1063 	unsigned long flags;
1064 	int to_drain;
1065 
1066 	local_irq_save(flags);
1067 	if (pcp->count >= pcp->batch)
1068 		to_drain = pcp->batch;
1069 	else
1070 		to_drain = pcp->count;
1071 	free_pcppages_bulk(zone, to_drain, pcp);
1072 	pcp->count -= to_drain;
1073 	local_irq_restore(flags);
1074 }
1075 #endif
1076 
1077 /*
1078  * Drain pages of the indicated processor.
1079  *
1080  * The processor must either be the current processor and the
1081  * thread pinned to the current processor or a processor that
1082  * is not online.
1083  */
drain_pages(unsigned int cpu)1084 static void drain_pages(unsigned int cpu)
1085 {
1086 	unsigned long flags;
1087 	struct zone *zone;
1088 
1089 	for_each_populated_zone(zone) {
1090 		struct per_cpu_pageset *pset;
1091 		struct per_cpu_pages *pcp;
1092 
1093 		local_irq_save(flags);
1094 		pset = per_cpu_ptr(zone->pageset, cpu);
1095 
1096 		pcp = &pset->pcp;
1097 		if (pcp->count) {
1098 			free_pcppages_bulk(zone, pcp->count, pcp);
1099 			pcp->count = 0;
1100 		}
1101 		local_irq_restore(flags);
1102 	}
1103 }
1104 
1105 /*
1106  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1107  */
drain_local_pages(void * arg)1108 void drain_local_pages(void *arg)
1109 {
1110 	drain_pages(smp_processor_id());
1111 }
1112 
1113 /*
1114  * Spill all the per-cpu pages from all CPUs back into the buddy allocator
1115  */
drain_all_pages(void)1116 void drain_all_pages(void)
1117 {
1118 	on_each_cpu(drain_local_pages, NULL, 1);
1119 }
1120 
1121 #ifdef CONFIG_HIBERNATION
1122 
mark_free_pages(struct zone * zone)1123 void mark_free_pages(struct zone *zone)
1124 {
1125 	unsigned long pfn, max_zone_pfn;
1126 	unsigned long flags;
1127 	int order, t;
1128 	struct list_head *curr;
1129 
1130 	if (!zone->spanned_pages)
1131 		return;
1132 
1133 	spin_lock_irqsave(&zone->lock, flags);
1134 
1135 	max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1136 	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1137 		if (pfn_valid(pfn)) {
1138 			struct page *page = pfn_to_page(pfn);
1139 
1140 			if (!swsusp_page_is_forbidden(page))
1141 				swsusp_unset_page_free(page);
1142 		}
1143 
1144 	for_each_migratetype_order(order, t) {
1145 		list_for_each(curr, &zone->free_area[order].free_list[t]) {
1146 			unsigned long i;
1147 
1148 			pfn = page_to_pfn(list_entry(curr, struct page, lru));
1149 			for (i = 0; i < (1UL << order); i++)
1150 				swsusp_set_page_free(pfn_to_page(pfn + i));
1151 		}
1152 	}
1153 	spin_unlock_irqrestore(&zone->lock, flags);
1154 }
1155 #endif /* CONFIG_PM */
1156 
1157 /*
1158  * Free a 0-order page
1159  * cold == 1 ? free a cold page : free a hot page
1160  */
free_hot_cold_page(struct page * page,int cold)1161 void free_hot_cold_page(struct page *page, int cold)
1162 {
1163 	struct zone *zone = page_zone(page);
1164 	struct per_cpu_pages *pcp;
1165 	unsigned long flags;
1166 	int migratetype;
1167 	int wasMlocked = __TestClearPageMlocked(page);
1168 
1169 	if (!free_pages_prepare(page, 0))
1170 		return;
1171 
1172 	migratetype = get_pageblock_migratetype(page);
1173 	set_page_private(page, migratetype);
1174 	local_irq_save(flags);
1175 	if (unlikely(wasMlocked))
1176 		free_page_mlock(page);
1177 	__count_vm_event(PGFREE);
1178 
1179 	/*
1180 	 * We only track unmovable, reclaimable and movable on pcp lists.
1181 	 * Free ISOLATE pages back to the allocator because they are being
1182 	 * offlined but treat RESERVE as movable pages so we can get those
1183 	 * areas back if necessary. Otherwise, we may have to free
1184 	 * excessively into the page allocator
1185 	 */
1186 	if (migratetype >= MIGRATE_PCPTYPES) {
1187 		if (unlikely(migratetype == MIGRATE_ISOLATE)) {
1188 			free_one_page(zone, page, 0, migratetype);
1189 			goto out;
1190 		}
1191 		migratetype = MIGRATE_MOVABLE;
1192 	}
1193 
1194 	pcp = &this_cpu_ptr(zone->pageset)->pcp;
1195 	if (cold)
1196 		list_add_tail(&page->lru, &pcp->lists[migratetype]);
1197 	else
1198 		list_add(&page->lru, &pcp->lists[migratetype]);
1199 	pcp->count++;
1200 	if (pcp->count >= pcp->high) {
1201 		free_pcppages_bulk(zone, pcp->batch, pcp);
1202 		pcp->count -= pcp->batch;
1203 	}
1204 
1205 out:
1206 	local_irq_restore(flags);
1207 }
1208 
1209 /*
1210  * split_page takes a non-compound higher-order page, and splits it into
1211  * n (1<<order) sub-pages: page[0..n]
1212  * Each sub-page must be freed individually.
1213  *
1214  * Note: this is probably too low level an operation for use in drivers.
1215  * Please consult with lkml before using this in your driver.
1216  */
split_page(struct page * page,unsigned int order)1217 void split_page(struct page *page, unsigned int order)
1218 {
1219 	int i;
1220 
1221 	VM_BUG_ON(PageCompound(page));
1222 	VM_BUG_ON(!page_count(page));
1223 
1224 #ifdef CONFIG_KMEMCHECK
1225 	/*
1226 	 * Split shadow pages too, because free(page[0]) would
1227 	 * otherwise free the whole shadow.
1228 	 */
1229 	if (kmemcheck_page_is_tracked(page))
1230 		split_page(virt_to_page(page[0].shadow), order);
1231 #endif
1232 
1233 	for (i = 1; i < (1 << order); i++)
1234 		set_page_refcounted(page + i);
1235 }
1236 
1237 /*
1238  * Similar to split_page except the page is already free. As this is only
1239  * being used for migration, the migratetype of the block also changes.
1240  * As this is called with interrupts disabled, the caller is responsible
1241  * for calling arch_alloc_page() and kernel_map_page() after interrupts
1242  * are enabled.
1243  *
1244  * Note: this is probably too low level an operation for use in drivers.
1245  * Please consult with lkml before using this in your driver.
1246  */
split_free_page(struct page * page)1247 int split_free_page(struct page *page)
1248 {
1249 	unsigned int order;
1250 	unsigned long watermark;
1251 	struct zone *zone;
1252 
1253 	BUG_ON(!PageBuddy(page));
1254 
1255 	zone = page_zone(page);
1256 	order = page_order(page);
1257 
1258 	/* Obey watermarks as if the page was being allocated */
1259 	watermark = low_wmark_pages(zone) + (1 << order);
1260 	if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1261 		return 0;
1262 
1263 	/* Remove page from free list */
1264 	list_del(&page->lru);
1265 	zone->free_area[order].nr_free--;
1266 	rmv_page_order(page);
1267 	__mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
1268 
1269 	/* Split into individual pages */
1270 	set_page_refcounted(page);
1271 	split_page(page, order);
1272 
1273 	if (order >= pageblock_order - 1) {
1274 		struct page *endpage = page + (1 << order) - 1;
1275 		for (; page < endpage; page += pageblock_nr_pages)
1276 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1277 	}
1278 
1279 	return 1 << order;
1280 }
1281 
1282 /*
1283  * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
1284  * we cheat by calling it from here, in the order > 0 path.  Saves a branch
1285  * or two.
1286  */
1287 static inline
buffered_rmqueue(struct zone * preferred_zone,struct zone * zone,int order,gfp_t gfp_flags,int migratetype)1288 struct page *buffered_rmqueue(struct zone *preferred_zone,
1289 			struct zone *zone, int order, gfp_t gfp_flags,
1290 			int migratetype)
1291 {
1292 	unsigned long flags;
1293 	struct page *page;
1294 	int cold = !!(gfp_flags & __GFP_COLD);
1295 
1296 again:
1297 	if (likely(order == 0)) {
1298 		struct per_cpu_pages *pcp;
1299 		struct list_head *list;
1300 
1301 		local_irq_save(flags);
1302 		pcp = &this_cpu_ptr(zone->pageset)->pcp;
1303 		list = &pcp->lists[migratetype];
1304 		if (list_empty(list)) {
1305 			pcp->count += rmqueue_bulk(zone, 0,
1306 					pcp->batch, list,
1307 					migratetype, cold);
1308 			if (unlikely(list_empty(list)))
1309 				goto failed;
1310 		}
1311 
1312 		if (cold)
1313 			page = list_entry(list->prev, struct page, lru);
1314 		else
1315 			page = list_entry(list->next, struct page, lru);
1316 
1317 		list_del(&page->lru);
1318 		pcp->count--;
1319 	} else {
1320 		if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1321 			/*
1322 			 * __GFP_NOFAIL is not to be used in new code.
1323 			 *
1324 			 * All __GFP_NOFAIL callers should be fixed so that they
1325 			 * properly detect and handle allocation failures.
1326 			 *
1327 			 * We most definitely don't want callers attempting to
1328 			 * allocate greater than order-1 page units with
1329 			 * __GFP_NOFAIL.
1330 			 */
1331 			WARN_ON_ONCE(order > 1);
1332 		}
1333 		spin_lock_irqsave(&zone->lock, flags);
1334 		page = __rmqueue(zone, order, migratetype);
1335 		spin_unlock(&zone->lock);
1336 		if (!page)
1337 			goto failed;
1338 		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
1339 	}
1340 
1341 	__count_zone_vm_events(PGALLOC, zone, 1 << order);
1342 	zone_statistics(preferred_zone, zone, gfp_flags);
1343 	local_irq_restore(flags);
1344 
1345 	VM_BUG_ON(bad_range(zone, page));
1346 	if (prep_new_page(page, order, gfp_flags))
1347 		goto again;
1348 	return page;
1349 
1350 failed:
1351 	local_irq_restore(flags);
1352 	return NULL;
1353 }
1354 
1355 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
1356 #define ALLOC_WMARK_MIN		WMARK_MIN
1357 #define ALLOC_WMARK_LOW		WMARK_LOW
1358 #define ALLOC_WMARK_HIGH	WMARK_HIGH
1359 #define ALLOC_NO_WATERMARKS	0x04 /* don't check watermarks at all */
1360 
1361 /* Mask to get the watermark bits */
1362 #define ALLOC_WMARK_MASK	(ALLOC_NO_WATERMARKS-1)
1363 
1364 #define ALLOC_HARDER		0x10 /* try to alloc harder */
1365 #define ALLOC_HIGH		0x20 /* __GFP_HIGH set */
1366 #define ALLOC_CPUSET		0x40 /* check for correct cpuset */
1367 
1368 #ifdef CONFIG_FAIL_PAGE_ALLOC
1369 
1370 static struct fail_page_alloc_attr {
1371 	struct fault_attr attr;
1372 
1373 	u32 ignore_gfp_highmem;
1374 	u32 ignore_gfp_wait;
1375 	u32 min_order;
1376 
1377 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1378 
1379 	struct dentry *ignore_gfp_highmem_file;
1380 	struct dentry *ignore_gfp_wait_file;
1381 	struct dentry *min_order_file;
1382 
1383 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1384 
1385 } fail_page_alloc = {
1386 	.attr = FAULT_ATTR_INITIALIZER,
1387 	.ignore_gfp_wait = 1,
1388 	.ignore_gfp_highmem = 1,
1389 	.min_order = 1,
1390 };
1391 
setup_fail_page_alloc(char * str)1392 static int __init setup_fail_page_alloc(char *str)
1393 {
1394 	return setup_fault_attr(&fail_page_alloc.attr, str);
1395 }
1396 __setup("fail_page_alloc=", setup_fail_page_alloc);
1397 
should_fail_alloc_page(gfp_t gfp_mask,unsigned int order)1398 static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1399 {
1400 	if (order < fail_page_alloc.min_order)
1401 		return 0;
1402 	if (gfp_mask & __GFP_NOFAIL)
1403 		return 0;
1404 	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1405 		return 0;
1406 	if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1407 		return 0;
1408 
1409 	return should_fail(&fail_page_alloc.attr, 1 << order);
1410 }
1411 
1412 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1413 
fail_page_alloc_debugfs(void)1414 static int __init fail_page_alloc_debugfs(void)
1415 {
1416 	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1417 	struct dentry *dir;
1418 	int err;
1419 
1420 	err = init_fault_attr_dentries(&fail_page_alloc.attr,
1421 				       "fail_page_alloc");
1422 	if (err)
1423 		return err;
1424 	dir = fail_page_alloc.attr.dentries.dir;
1425 
1426 	fail_page_alloc.ignore_gfp_wait_file =
1427 		debugfs_create_bool("ignore-gfp-wait", mode, dir,
1428 				      &fail_page_alloc.ignore_gfp_wait);
1429 
1430 	fail_page_alloc.ignore_gfp_highmem_file =
1431 		debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1432 				      &fail_page_alloc.ignore_gfp_highmem);
1433 	fail_page_alloc.min_order_file =
1434 		debugfs_create_u32("min-order", mode, dir,
1435 				   &fail_page_alloc.min_order);
1436 
1437 	if (!fail_page_alloc.ignore_gfp_wait_file ||
1438             !fail_page_alloc.ignore_gfp_highmem_file ||
1439             !fail_page_alloc.min_order_file) {
1440 		err = -ENOMEM;
1441 		debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
1442 		debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
1443 		debugfs_remove(fail_page_alloc.min_order_file);
1444 		cleanup_fault_attr_dentries(&fail_page_alloc.attr);
1445 	}
1446 
1447 	return err;
1448 }
1449 
1450 late_initcall(fail_page_alloc_debugfs);
1451 
1452 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1453 
1454 #else /* CONFIG_FAIL_PAGE_ALLOC */
1455 
should_fail_alloc_page(gfp_t gfp_mask,unsigned int order)1456 static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1457 {
1458 	return 0;
1459 }
1460 
1461 #endif /* CONFIG_FAIL_PAGE_ALLOC */
1462 
1463 /*
1464  * Return true if free pages are above 'mark'. This takes into account the order
1465  * of the allocation.
1466  */
__zone_watermark_ok(struct zone * z,int order,unsigned long mark,int classzone_idx,int alloc_flags,long free_pages)1467 static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1468 		      int classzone_idx, int alloc_flags, long free_pages)
1469 {
1470 	/* free_pages my go negative - that's OK */
1471 	long min = mark;
1472 	int o;
1473 
1474 	free_pages -= (1 << order) + 1;
1475 	if (alloc_flags & ALLOC_HIGH)
1476 		min -= min / 2;
1477 	if (alloc_flags & ALLOC_HARDER)
1478 		min -= min / 4;
1479 
1480 	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1481 		return false;
1482 	for (o = 0; o < order; o++) {
1483 		/* At the next order, this order's pages become unavailable */
1484 		free_pages -= z->free_area[o].nr_free << o;
1485 
1486 		/* Require fewer higher order pages to be free */
1487 		min >>= 1;
1488 
1489 		if (free_pages <= min)
1490 			return false;
1491 	}
1492 	return true;
1493 }
1494 
zone_watermark_ok(struct zone * z,int order,unsigned long mark,int classzone_idx,int alloc_flags)1495 bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1496 		      int classzone_idx, int alloc_flags)
1497 {
1498 	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1499 					zone_page_state(z, NR_FREE_PAGES));
1500 }
1501 
zone_watermark_ok_safe(struct zone * z,int order,unsigned long mark,int classzone_idx,int alloc_flags)1502 bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1503 		      int classzone_idx, int alloc_flags)
1504 {
1505 	long free_pages = zone_page_state(z, NR_FREE_PAGES);
1506 
1507 	if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1508 		free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1509 
1510 	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1511 								free_pages);
1512 }
1513 
1514 #ifdef CONFIG_NUMA
1515 /*
1516  * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
1517  * skip over zones that are not allowed by the cpuset, or that have
1518  * been recently (in last second) found to be nearly full.  See further
1519  * comments in mmzone.h.  Reduces cache footprint of zonelist scans
1520  * that have to skip over a lot of full or unallowed zones.
1521  *
1522  * If the zonelist cache is present in the passed in zonelist, then
1523  * returns a pointer to the allowed node mask (either the current
1524  * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
1525  *
1526  * If the zonelist cache is not available for this zonelist, does
1527  * nothing and returns NULL.
1528  *
1529  * If the fullzones BITMAP in the zonelist cache is stale (more than
1530  * a second since last zap'd) then we zap it out (clear its bits.)
1531  *
1532  * We hold off even calling zlc_setup, until after we've checked the
1533  * first zone in the zonelist, on the theory that most allocations will
1534  * be satisfied from that first zone, so best to examine that zone as
1535  * quickly as we can.
1536  */
zlc_setup(struct zonelist * zonelist,int alloc_flags)1537 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1538 {
1539 	struct zonelist_cache *zlc;	/* cached zonelist speedup info */
1540 	nodemask_t *allowednodes;	/* zonelist_cache approximation */
1541 
1542 	zlc = zonelist->zlcache_ptr;
1543 	if (!zlc)
1544 		return NULL;
1545 
1546 	if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1547 		bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1548 		zlc->last_full_zap = jiffies;
1549 	}
1550 
1551 	allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1552 					&cpuset_current_mems_allowed :
1553 					&node_states[N_HIGH_MEMORY];
1554 	return allowednodes;
1555 }
1556 
1557 /*
1558  * Given 'z' scanning a zonelist, run a couple of quick checks to see
1559  * if it is worth looking at further for free memory:
1560  *  1) Check that the zone isn't thought to be full (doesn't have its
1561  *     bit set in the zonelist_cache fullzones BITMAP).
1562  *  2) Check that the zones node (obtained from the zonelist_cache
1563  *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1564  * Return true (non-zero) if zone is worth looking at further, or
1565  * else return false (zero) if it is not.
1566  *
1567  * This check -ignores- the distinction between various watermarks,
1568  * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
1569  * found to be full for any variation of these watermarks, it will
1570  * be considered full for up to one second by all requests, unless
1571  * we are so low on memory on all allowed nodes that we are forced
1572  * into the second scan of the zonelist.
1573  *
1574  * In the second scan we ignore this zonelist cache and exactly
1575  * apply the watermarks to all zones, even it is slower to do so.
1576  * We are low on memory in the second scan, and should leave no stone
1577  * unturned looking for a free page.
1578  */
zlc_zone_worth_trying(struct zonelist * zonelist,struct zoneref * z,nodemask_t * allowednodes)1579 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1580 						nodemask_t *allowednodes)
1581 {
1582 	struct zonelist_cache *zlc;	/* cached zonelist speedup info */
1583 	int i;				/* index of *z in zonelist zones */
1584 	int n;				/* node that zone *z is on */
1585 
1586 	zlc = zonelist->zlcache_ptr;
1587 	if (!zlc)
1588 		return 1;
1589 
1590 	i = z - zonelist->_zonerefs;
1591 	n = zlc->z_to_n[i];
1592 
1593 	/* This zone is worth trying if it is allowed but not full */
1594 	return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1595 }
1596 
1597 /*
1598  * Given 'z' scanning a zonelist, set the corresponding bit in
1599  * zlc->fullzones, so that subsequent attempts to allocate a page
1600  * from that zone don't waste time re-examining it.
1601  */
zlc_mark_zone_full(struct zonelist * zonelist,struct zoneref * z)1602 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1603 {
1604 	struct zonelist_cache *zlc;	/* cached zonelist speedup info */
1605 	int i;				/* index of *z in zonelist zones */
1606 
1607 	zlc = zonelist->zlcache_ptr;
1608 	if (!zlc)
1609 		return;
1610 
1611 	i = z - zonelist->_zonerefs;
1612 
1613 	set_bit(i, zlc->fullzones);
1614 }
1615 
1616 #else	/* CONFIG_NUMA */
1617 
zlc_setup(struct zonelist * zonelist,int alloc_flags)1618 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1619 {
1620 	return NULL;
1621 }
1622 
zlc_zone_worth_trying(struct zonelist * zonelist,struct zoneref * z,nodemask_t * allowednodes)1623 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1624 				nodemask_t *allowednodes)
1625 {
1626 	return 1;
1627 }
1628 
zlc_mark_zone_full(struct zonelist * zonelist,struct zoneref * z)1629 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1630 {
1631 }
1632 #endif	/* CONFIG_NUMA */
1633 
1634 /*
1635  * get_page_from_freelist goes through the zonelist trying to allocate
1636  * a page.
1637  */
1638 static struct page *
get_page_from_freelist(gfp_t gfp_mask,nodemask_t * nodemask,unsigned int order,struct zonelist * zonelist,int high_zoneidx,int alloc_flags,struct zone * preferred_zone,int migratetype)1639 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1640 		struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1641 		struct zone *preferred_zone, int migratetype)
1642 {
1643 	struct zoneref *z;
1644 	struct page *page = NULL;
1645 	int classzone_idx;
1646 	struct zone *zone;
1647 	nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1648 	int zlc_active = 0;		/* set if using zonelist_cache */
1649 	int did_zlc_setup = 0;		/* just call zlc_setup() one time */
1650 
1651 	classzone_idx = zone_idx(preferred_zone);
1652 zonelist_scan:
1653 	/*
1654 	 * Scan zonelist, looking for a zone with enough free.
1655 	 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1656 	 */
1657 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
1658 						high_zoneidx, nodemask) {
1659 		if (NUMA_BUILD && zlc_active &&
1660 			!zlc_zone_worth_trying(zonelist, z, allowednodes))
1661 				continue;
1662 		if ((alloc_flags & ALLOC_CPUSET) &&
1663 			!cpuset_zone_allowed_softwall(zone, gfp_mask))
1664 				goto try_next_zone;
1665 
1666 		BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1667 		if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1668 			unsigned long mark;
1669 			int ret;
1670 
1671 			mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1672 			if (zone_watermark_ok(zone, order, mark,
1673 				    classzone_idx, alloc_flags))
1674 				goto try_this_zone;
1675 
1676 			if (zone_reclaim_mode == 0)
1677 				goto this_zone_full;
1678 
1679 			ret = zone_reclaim(zone, gfp_mask, order);
1680 			switch (ret) {
1681 			case ZONE_RECLAIM_NOSCAN:
1682 				/* did not scan */
1683 				goto try_next_zone;
1684 			case ZONE_RECLAIM_FULL:
1685 				/* scanned but unreclaimable */
1686 				goto this_zone_full;
1687 			default:
1688 				/* did we reclaim enough */
1689 				if (!zone_watermark_ok(zone, order, mark,
1690 						classzone_idx, alloc_flags))
1691 					goto this_zone_full;
1692 			}
1693 		}
1694 
1695 try_this_zone:
1696 		page = buffered_rmqueue(preferred_zone, zone, order,
1697 						gfp_mask, migratetype);
1698 		if (page)
1699 			break;
1700 this_zone_full:
1701 		if (NUMA_BUILD)
1702 			zlc_mark_zone_full(zonelist, z);
1703 try_next_zone:
1704 		if (NUMA_BUILD && !did_zlc_setup && nr_online_nodes > 1) {
1705 			/*
1706 			 * we do zlc_setup after the first zone is tried but only
1707 			 * if there are multiple nodes make it worthwhile
1708 			 */
1709 			allowednodes = zlc_setup(zonelist, alloc_flags);
1710 			zlc_active = 1;
1711 			did_zlc_setup = 1;
1712 		}
1713 	}
1714 
1715 	if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1716 		/* Disable zlc cache for second zonelist scan */
1717 		zlc_active = 0;
1718 		goto zonelist_scan;
1719 	}
1720 	return page;
1721 }
1722 
1723 /*
1724  * Large machines with many possible nodes should not always dump per-node
1725  * meminfo in irq context.
1726  */
should_suppress_show_mem(void)1727 static inline bool should_suppress_show_mem(void)
1728 {
1729 	bool ret = false;
1730 
1731 #if NODES_SHIFT > 8
1732 	ret = in_interrupt();
1733 #endif
1734 	return ret;
1735 }
1736 
1737 static inline int
should_alloc_retry(gfp_t gfp_mask,unsigned int order,unsigned long pages_reclaimed)1738 should_alloc_retry(gfp_t gfp_mask, unsigned int order,
1739 				unsigned long pages_reclaimed)
1740 {
1741 	/* Do not loop if specifically requested */
1742 	if (gfp_mask & __GFP_NORETRY)
1743 		return 0;
1744 
1745 	/*
1746 	 * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
1747 	 * means __GFP_NOFAIL, but that may not be true in other
1748 	 * implementations.
1749 	 */
1750 	if (order <= PAGE_ALLOC_COSTLY_ORDER)
1751 		return 1;
1752 
1753 	/*
1754 	 * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
1755 	 * specified, then we retry until we no longer reclaim any pages
1756 	 * (above), or we've reclaimed an order of pages at least as
1757 	 * large as the allocation's order. In both cases, if the
1758 	 * allocation still fails, we stop retrying.
1759 	 */
1760 	if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
1761 		return 1;
1762 
1763 	/*
1764 	 * Don't let big-order allocations loop unless the caller
1765 	 * explicitly requests that.
1766 	 */
1767 	if (gfp_mask & __GFP_NOFAIL)
1768 		return 1;
1769 
1770 	return 0;
1771 }
1772 
1773 static inline struct page *
__alloc_pages_may_oom(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,nodemask_t * nodemask,struct zone * preferred_zone,int migratetype)1774 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
1775 	struct zonelist *zonelist, enum zone_type high_zoneidx,
1776 	nodemask_t *nodemask, struct zone *preferred_zone,
1777 	int migratetype)
1778 {
1779 	struct page *page;
1780 
1781 	/* Acquire the OOM killer lock for the zones in zonelist */
1782 	if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
1783 		schedule_timeout_uninterruptible(1);
1784 		return NULL;
1785 	}
1786 
1787 	/*
1788 	 * Go through the zonelist yet one more time, keep very high watermark
1789 	 * here, this is only to catch a parallel oom killing, we must fail if
1790 	 * we're still under heavy pressure.
1791 	 */
1792 	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
1793 		order, zonelist, high_zoneidx,
1794 		ALLOC_WMARK_HIGH|ALLOC_CPUSET,
1795 		preferred_zone, migratetype);
1796 	if (page)
1797 		goto out;
1798 
1799 	if (!(gfp_mask & __GFP_NOFAIL)) {
1800 		/* The OOM killer will not help higher order allocs */
1801 		if (order > PAGE_ALLOC_COSTLY_ORDER)
1802 			goto out;
1803 		/* The OOM killer does not needlessly kill tasks for lowmem */
1804 		if (high_zoneidx < ZONE_NORMAL)
1805 			goto out;
1806 		/*
1807 		 * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
1808 		 * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
1809 		 * The caller should handle page allocation failure by itself if
1810 		 * it specifies __GFP_THISNODE.
1811 		 * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
1812 		 */
1813 		if (gfp_mask & __GFP_THISNODE)
1814 			goto out;
1815 	}
1816 	/* Exhausted what can be done so it's blamo time */
1817 	out_of_memory(zonelist, gfp_mask, order, nodemask);
1818 
1819 out:
1820 	clear_zonelist_oom(zonelist, gfp_mask);
1821 	return page;
1822 }
1823 
1824 #ifdef CONFIG_COMPACTION
1825 /* Try memory compaction for high-order allocations before reclaim */
1826 static struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,nodemask_t * nodemask,int alloc_flags,struct zone * preferred_zone,int migratetype,unsigned long * did_some_progress,bool sync_migration)1827 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1828 	struct zonelist *zonelist, enum zone_type high_zoneidx,
1829 	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1830 	int migratetype, unsigned long *did_some_progress,
1831 	bool sync_migration)
1832 {
1833 	struct page *page;
1834 
1835 	if (!order || compaction_deferred(preferred_zone))
1836 		return NULL;
1837 
1838 	current->flags |= PF_MEMALLOC;
1839 	*did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
1840 						nodemask, sync_migration);
1841 	current->flags &= ~PF_MEMALLOC;
1842 	if (*did_some_progress != COMPACT_SKIPPED) {
1843 
1844 		/* Page migration frees to the PCP lists but we want merging */
1845 		drain_pages(get_cpu());
1846 		put_cpu();
1847 
1848 		page = get_page_from_freelist(gfp_mask, nodemask,
1849 				order, zonelist, high_zoneidx,
1850 				alloc_flags, preferred_zone,
1851 				migratetype);
1852 		if (page) {
1853 			preferred_zone->compact_considered = 0;
1854 			preferred_zone->compact_defer_shift = 0;
1855 			count_vm_event(COMPACTSUCCESS);
1856 			return page;
1857 		}
1858 
1859 		/*
1860 		 * It's bad if compaction run occurs and fails.
1861 		 * The most likely reason is that pages exist,
1862 		 * but not enough to satisfy watermarks.
1863 		 */
1864 		count_vm_event(COMPACTFAIL);
1865 		defer_compaction(preferred_zone);
1866 
1867 		cond_resched();
1868 	}
1869 
1870 	return NULL;
1871 }
1872 #else
1873 static inline struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,nodemask_t * nodemask,int alloc_flags,struct zone * preferred_zone,int migratetype,unsigned long * did_some_progress,bool sync_migration)1874 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1875 	struct zonelist *zonelist, enum zone_type high_zoneidx,
1876 	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1877 	int migratetype, unsigned long *did_some_progress,
1878 	bool sync_migration)
1879 {
1880 	return NULL;
1881 }
1882 #endif /* CONFIG_COMPACTION */
1883 
1884 /* The really slow allocator path where we enter direct reclaim */
1885 static inline struct page *
__alloc_pages_direct_reclaim(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,nodemask_t * nodemask,int alloc_flags,struct zone * preferred_zone,int migratetype,unsigned long * did_some_progress)1886 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
1887 	struct zonelist *zonelist, enum zone_type high_zoneidx,
1888 	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1889 	int migratetype, unsigned long *did_some_progress)
1890 {
1891 	struct page *page = NULL;
1892 	struct reclaim_state reclaim_state;
1893 	bool drained = false;
1894 
1895 	cond_resched();
1896 
1897 	/* We now go into synchronous reclaim */
1898 	cpuset_memory_pressure_bump();
1899 	current->flags |= PF_MEMALLOC;
1900 	lockdep_set_current_reclaim_state(gfp_mask);
1901 	reclaim_state.reclaimed_slab = 0;
1902 	current->reclaim_state = &reclaim_state;
1903 
1904 	*did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
1905 
1906 	current->reclaim_state = NULL;
1907 	lockdep_clear_current_reclaim_state();
1908 	current->flags &= ~PF_MEMALLOC;
1909 
1910 	cond_resched();
1911 
1912 	if (unlikely(!(*did_some_progress)))
1913 		return NULL;
1914 
1915 retry:
1916 	page = get_page_from_freelist(gfp_mask, nodemask, order,
1917 					zonelist, high_zoneidx,
1918 					alloc_flags, preferred_zone,
1919 					migratetype);
1920 
1921 	/*
1922 	 * If an allocation failed after direct reclaim, it could be because
1923 	 * pages are pinned on the per-cpu lists. Drain them and try again
1924 	 */
1925 	if (!page && !drained) {
1926 		drain_all_pages();
1927 		drained = true;
1928 		goto retry;
1929 	}
1930 
1931 	return page;
1932 }
1933 
1934 /*
1935  * This is called in the allocator slow-path if the allocation request is of
1936  * sufficient urgency to ignore watermarks and take other desperate measures
1937  */
1938 static inline struct page *
__alloc_pages_high_priority(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,nodemask_t * nodemask,struct zone * preferred_zone,int migratetype)1939 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
1940 	struct zonelist *zonelist, enum zone_type high_zoneidx,
1941 	nodemask_t *nodemask, struct zone *preferred_zone,
1942 	int migratetype)
1943 {
1944 	struct page *page;
1945 
1946 	do {
1947 		page = get_page_from_freelist(gfp_mask, nodemask, order,
1948 			zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
1949 			preferred_zone, migratetype);
1950 
1951 		if (!page && gfp_mask & __GFP_NOFAIL)
1952 			wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
1953 	} while (!page && (gfp_mask & __GFP_NOFAIL));
1954 
1955 	return page;
1956 }
1957 
1958 static inline
wake_all_kswapd(unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,enum zone_type classzone_idx)1959 void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
1960 						enum zone_type high_zoneidx,
1961 						enum zone_type classzone_idx)
1962 {
1963 	struct zoneref *z;
1964 	struct zone *zone;
1965 
1966 	for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
1967 		wakeup_kswapd(zone, order, classzone_idx);
1968 }
1969 
1970 static inline int
gfp_to_alloc_flags(gfp_t gfp_mask)1971 gfp_to_alloc_flags(gfp_t gfp_mask)
1972 {
1973 	int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
1974 	const gfp_t wait = gfp_mask & __GFP_WAIT;
1975 
1976 	/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
1977 	BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
1978 
1979 	/*
1980 	 * The caller may dip into page reserves a bit more if the caller
1981 	 * cannot run direct reclaim, or if the caller has realtime scheduling
1982 	 * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
1983 	 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
1984 	 */
1985 	alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
1986 
1987 	if (!wait) {
1988 		/*
1989 		 * Not worth trying to allocate harder for
1990 		 * __GFP_NOMEMALLOC even if it can't schedule.
1991 		 */
1992 		if  (!(gfp_mask & __GFP_NOMEMALLOC))
1993 			alloc_flags |= ALLOC_HARDER;
1994 		/*
1995 		 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
1996 		 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1997 		 */
1998 		alloc_flags &= ~ALLOC_CPUSET;
1999 	} else if (unlikely(rt_task(current)) && !in_interrupt())
2000 		alloc_flags |= ALLOC_HARDER;
2001 
2002 	if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2003 		if (!in_interrupt() &&
2004 		    ((current->flags & PF_MEMALLOC) ||
2005 		     unlikely(test_thread_flag(TIF_MEMDIE))))
2006 			alloc_flags |= ALLOC_NO_WATERMARKS;
2007 	}
2008 
2009 	return alloc_flags;
2010 }
2011 
2012 static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,enum zone_type high_zoneidx,nodemask_t * nodemask,struct zone * preferred_zone,int migratetype)2013 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2014 	struct zonelist *zonelist, enum zone_type high_zoneidx,
2015 	nodemask_t *nodemask, struct zone *preferred_zone,
2016 	int migratetype)
2017 {
2018 	const gfp_t wait = gfp_mask & __GFP_WAIT;
2019 	struct page *page = NULL;
2020 	int alloc_flags;
2021 	unsigned long pages_reclaimed = 0;
2022 	unsigned long did_some_progress;
2023 	bool sync_migration = false;
2024 
2025 	/*
2026 	 * In the slowpath, we sanity check order to avoid ever trying to
2027 	 * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2028 	 * be using allocators in order of preference for an area that is
2029 	 * too large.
2030 	 */
2031 	if (order >= MAX_ORDER) {
2032 		WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2033 		return NULL;
2034 	}
2035 
2036 	/*
2037 	 * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2038 	 * __GFP_NOWARN set) should not cause reclaim since the subsystem
2039 	 * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2040 	 * using a larger set of nodes after it has established that the
2041 	 * allowed per node queues are empty and that nodes are
2042 	 * over allocated.
2043 	 */
2044 	if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2045 		goto nopage;
2046 
2047 restart:
2048 	if (!(gfp_mask & __GFP_NO_KSWAPD))
2049 		wake_all_kswapd(order, zonelist, high_zoneidx,
2050 						zone_idx(preferred_zone));
2051 
2052 	/*
2053 	 * OK, we're below the kswapd watermark and have kicked background
2054 	 * reclaim. Now things get more complex, so set up alloc_flags according
2055 	 * to how we want to proceed.
2056 	 */
2057 	alloc_flags = gfp_to_alloc_flags(gfp_mask);
2058 
2059 	/*
2060 	 * Find the true preferred zone if the allocation is unconstrained by
2061 	 * cpusets.
2062 	 */
2063 	if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2064 		first_zones_zonelist(zonelist, high_zoneidx, NULL,
2065 					&preferred_zone);
2066 
2067 	/* This is the last chance, in general, before the goto nopage. */
2068 	page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2069 			high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2070 			preferred_zone, migratetype);
2071 	if (page)
2072 		goto got_pg;
2073 
2074 rebalance:
2075 	/* Allocate without watermarks if the context allows */
2076 	if (alloc_flags & ALLOC_NO_WATERMARKS) {
2077 		page = __alloc_pages_high_priority(gfp_mask, order,
2078 				zonelist, high_zoneidx, nodemask,
2079 				preferred_zone, migratetype);
2080 		if (page)
2081 			goto got_pg;
2082 	}
2083 
2084 	/* Atomic allocations - we can't balance anything */
2085 	if (!wait)
2086 		goto nopage;
2087 
2088 	/* Avoid recursion of direct reclaim */
2089 	if (current->flags & PF_MEMALLOC)
2090 		goto nopage;
2091 
2092 	/* Avoid allocations with no watermarks from looping endlessly */
2093 	if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2094 		goto nopage;
2095 
2096 	/*
2097 	 * Try direct compaction. The first pass is asynchronous. Subsequent
2098 	 * attempts after direct reclaim are synchronous
2099 	 */
2100 	page = __alloc_pages_direct_compact(gfp_mask, order,
2101 					zonelist, high_zoneidx,
2102 					nodemask,
2103 					alloc_flags, preferred_zone,
2104 					migratetype, &did_some_progress,
2105 					sync_migration);
2106 	if (page)
2107 		goto got_pg;
2108 	sync_migration = !(gfp_mask & __GFP_NO_KSWAPD);
2109 
2110 	/* Try direct reclaim and then allocating */
2111 	page = __alloc_pages_direct_reclaim(gfp_mask, order,
2112 					zonelist, high_zoneidx,
2113 					nodemask,
2114 					alloc_flags, preferred_zone,
2115 					migratetype, &did_some_progress);
2116 	if (page)
2117 		goto got_pg;
2118 
2119 	/*
2120 	 * If we failed to make any progress reclaiming, then we are
2121 	 * running out of options and have to consider going OOM
2122 	 */
2123 	if (!did_some_progress) {
2124 		if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2125 			if (oom_killer_disabled)
2126 				goto nopage;
2127 			page = __alloc_pages_may_oom(gfp_mask, order,
2128 					zonelist, high_zoneidx,
2129 					nodemask, preferred_zone,
2130 					migratetype);
2131 			if (page)
2132 				goto got_pg;
2133 
2134 			if (!(gfp_mask & __GFP_NOFAIL)) {
2135 				/*
2136 				 * The oom killer is not called for high-order
2137 				 * allocations that may fail, so if no progress
2138 				 * is being made, there are no other options and
2139 				 * retrying is unlikely to help.
2140 				 */
2141 				if (order > PAGE_ALLOC_COSTLY_ORDER)
2142 					goto nopage;
2143 				/*
2144 				 * The oom killer is not called for lowmem
2145 				 * allocations to prevent needlessly killing
2146 				 * innocent tasks.
2147 				 */
2148 				if (high_zoneidx < ZONE_NORMAL)
2149 					goto nopage;
2150 			}
2151 
2152 			goto restart;
2153 		}
2154 	}
2155 
2156 	/* Check if we should retry the allocation */
2157 	pages_reclaimed += did_some_progress;
2158 	if (should_alloc_retry(gfp_mask, order, pages_reclaimed)) {
2159 		/* Wait for some write requests to complete then retry */
2160 		wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2161 		goto rebalance;
2162 	} else {
2163 		/*
2164 		 * High-order allocations do not necessarily loop after
2165 		 * direct reclaim and reclaim/compaction depends on compaction
2166 		 * being called after reclaim so call directly if necessary
2167 		 */
2168 		page = __alloc_pages_direct_compact(gfp_mask, order,
2169 					zonelist, high_zoneidx,
2170 					nodemask,
2171 					alloc_flags, preferred_zone,
2172 					migratetype, &did_some_progress,
2173 					sync_migration);
2174 		if (page)
2175 			goto got_pg;
2176 	}
2177 
2178 nopage:
2179 	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
2180 		unsigned int filter = SHOW_MEM_FILTER_NODES;
2181 
2182 		/*
2183 		 * This documents exceptions given to allocations in certain
2184 		 * contexts that are allowed to allocate outside current's set
2185 		 * of allowed nodes.
2186 		 */
2187 		if (!(gfp_mask & __GFP_NOMEMALLOC))
2188 			if (test_thread_flag(TIF_MEMDIE) ||
2189 			    (current->flags & (PF_MEMALLOC | PF_EXITING)))
2190 				filter &= ~SHOW_MEM_FILTER_NODES;
2191 		if (in_interrupt() || !wait)
2192 			filter &= ~SHOW_MEM_FILTER_NODES;
2193 
2194 		pr_warning("%s: page allocation failure. order:%d, mode:0x%x\n",
2195 			current->comm, order, gfp_mask);
2196 		dump_stack();
2197 		if (!should_suppress_show_mem())
2198 			show_mem(filter);
2199 	}
2200 	return page;
2201 got_pg:
2202 	if (kmemcheck_enabled)
2203 		kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2204 	return page;
2205 
2206 }
2207 
2208 /*
2209  * This is the 'heart' of the zoned buddy allocator.
2210  */
2211 struct page *
__alloc_pages_nodemask(gfp_t gfp_mask,unsigned int order,struct zonelist * zonelist,nodemask_t * nodemask)2212 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2213 			struct zonelist *zonelist, nodemask_t *nodemask)
2214 {
2215 	enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2216 	struct zone *preferred_zone;
2217 	struct page *page;
2218 	int migratetype = allocflags_to_migratetype(gfp_mask);
2219 
2220 	gfp_mask &= gfp_allowed_mask;
2221 
2222 	lockdep_trace_alloc(gfp_mask);
2223 
2224 	might_sleep_if(gfp_mask & __GFP_WAIT);
2225 
2226 	if (should_fail_alloc_page(gfp_mask, order))
2227 		return NULL;
2228 
2229 	/*
2230 	 * Check the zones suitable for the gfp_mask contain at least one
2231 	 * valid zone. It's possible to have an empty zonelist as a result
2232 	 * of GFP_THISNODE and a memoryless node
2233 	 */
2234 	if (unlikely(!zonelist->_zonerefs->zone))
2235 		return NULL;
2236 
2237 	get_mems_allowed();
2238 	/* The preferred zone is used for statistics later */
2239 	first_zones_zonelist(zonelist, high_zoneidx,
2240 				nodemask ? : &cpuset_current_mems_allowed,
2241 				&preferred_zone);
2242 	if (!preferred_zone) {
2243 		put_mems_allowed();
2244 		return NULL;
2245 	}
2246 
2247 	/* First allocation attempt */
2248 	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2249 			zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
2250 			preferred_zone, migratetype);
2251 	if (unlikely(!page))
2252 		page = __alloc_pages_slowpath(gfp_mask, order,
2253 				zonelist, high_zoneidx, nodemask,
2254 				preferred_zone, migratetype);
2255 	put_mems_allowed();
2256 
2257 	trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2258 	return page;
2259 }
2260 EXPORT_SYMBOL(__alloc_pages_nodemask);
2261 
2262 /*
2263  * Common helper functions.
2264  */
__get_free_pages(gfp_t gfp_mask,unsigned int order)2265 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2266 {
2267 	struct page *page;
2268 
2269 	/*
2270 	 * __get_free_pages() returns a 32-bit address, which cannot represent
2271 	 * a highmem page
2272 	 */
2273 	VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2274 
2275 	page = alloc_pages(gfp_mask, order);
2276 	if (!page)
2277 		return 0;
2278 	return (unsigned long) page_address(page);
2279 }
2280 EXPORT_SYMBOL(__get_free_pages);
2281 
get_zeroed_page(gfp_t gfp_mask)2282 unsigned long get_zeroed_page(gfp_t gfp_mask)
2283 {
2284 	return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2285 }
2286 EXPORT_SYMBOL(get_zeroed_page);
2287 
__pagevec_free(struct pagevec * pvec)2288 void __pagevec_free(struct pagevec *pvec)
2289 {
2290 	int i = pagevec_count(pvec);
2291 
2292 	while (--i >= 0) {
2293 		trace_mm_pagevec_free(pvec->pages[i], pvec->cold);
2294 		free_hot_cold_page(pvec->pages[i], pvec->cold);
2295 	}
2296 }
2297 
__free_pages(struct page * page,unsigned int order)2298 void __free_pages(struct page *page, unsigned int order)
2299 {
2300 	if (put_page_testzero(page)) {
2301 		if (order == 0)
2302 			free_hot_cold_page(page, 0);
2303 		else
2304 			__free_pages_ok(page, order);
2305 	}
2306 }
2307 
2308 EXPORT_SYMBOL(__free_pages);
2309 
free_pages(unsigned long addr,unsigned int order)2310 void free_pages(unsigned long addr, unsigned int order)
2311 {
2312 	if (addr != 0) {
2313 		VM_BUG_ON(!virt_addr_valid((void *)addr));
2314 		__free_pages(virt_to_page((void *)addr), order);
2315 	}
2316 }
2317 
2318 EXPORT_SYMBOL(free_pages);
2319 
make_alloc_exact(unsigned long addr,unsigned order,size_t size)2320 static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2321 {
2322 	if (addr) {
2323 		unsigned long alloc_end = addr + (PAGE_SIZE << order);
2324 		unsigned long used = addr + PAGE_ALIGN(size);
2325 
2326 		split_page(virt_to_page((void *)addr), order);
2327 		while (used < alloc_end) {
2328 			free_page(used);
2329 			used += PAGE_SIZE;
2330 		}
2331 	}
2332 	return (void *)addr;
2333 }
2334 
2335 /**
2336  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2337  * @size: the number of bytes to allocate
2338  * @gfp_mask: GFP flags for the allocation
2339  *
2340  * This function is similar to alloc_pages(), except that it allocates the
2341  * minimum number of pages to satisfy the request.  alloc_pages() can only
2342  * allocate memory in power-of-two pages.
2343  *
2344  * This function is also limited by MAX_ORDER.
2345  *
2346  * Memory allocated by this function must be released by free_pages_exact().
2347  */
alloc_pages_exact(size_t size,gfp_t gfp_mask)2348 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2349 {
2350 	unsigned int order = get_order(size);
2351 	unsigned long addr;
2352 
2353 	addr = __get_free_pages(gfp_mask, order);
2354 	return make_alloc_exact(addr, order, size);
2355 }
2356 EXPORT_SYMBOL(alloc_pages_exact);
2357 
2358 /**
2359  * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2360  *			   pages on a node.
2361  * @nid: the preferred node ID where memory should be allocated
2362  * @size: the number of bytes to allocate
2363  * @gfp_mask: GFP flags for the allocation
2364  *
2365  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2366  * back.
2367  * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2368  * but is not exact.
2369  */
alloc_pages_exact_nid(int nid,size_t size,gfp_t gfp_mask)2370 void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2371 {
2372 	unsigned order = get_order(size);
2373 	struct page *p = alloc_pages_node(nid, gfp_mask, order);
2374 	if (!p)
2375 		return NULL;
2376 	return make_alloc_exact((unsigned long)page_address(p), order, size);
2377 }
2378 EXPORT_SYMBOL(alloc_pages_exact_nid);
2379 
2380 /**
2381  * free_pages_exact - release memory allocated via alloc_pages_exact()
2382  * @virt: the value returned by alloc_pages_exact.
2383  * @size: size of allocation, same value as passed to alloc_pages_exact().
2384  *
2385  * Release the memory allocated by a previous call to alloc_pages_exact.
2386  */
free_pages_exact(void * virt,size_t size)2387 void free_pages_exact(void *virt, size_t size)
2388 {
2389 	unsigned long addr = (unsigned long)virt;
2390 	unsigned long end = addr + PAGE_ALIGN(size);
2391 
2392 	while (addr < end) {
2393 		free_page(addr);
2394 		addr += PAGE_SIZE;
2395 	}
2396 }
2397 EXPORT_SYMBOL(free_pages_exact);
2398 
nr_free_zone_pages(int offset)2399 static unsigned int nr_free_zone_pages(int offset)
2400 {
2401 	struct zoneref *z;
2402 	struct zone *zone;
2403 
2404 	/* Just pick one node, since fallback list is circular */
2405 	unsigned int sum = 0;
2406 
2407 	struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2408 
2409 	for_each_zone_zonelist(zone, z, zonelist, offset) {
2410 		unsigned long size = zone->present_pages;
2411 		unsigned long high = high_wmark_pages(zone);
2412 		if (size > high)
2413 			sum += size - high;
2414 	}
2415 
2416 	return sum;
2417 }
2418 
2419 /*
2420  * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
2421  */
nr_free_buffer_pages(void)2422 unsigned int nr_free_buffer_pages(void)
2423 {
2424 	return nr_free_zone_pages(gfp_zone(GFP_USER));
2425 }
2426 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2427 
2428 /*
2429  * Amount of free RAM allocatable within all zones
2430  */
nr_free_pagecache_pages(void)2431 unsigned int nr_free_pagecache_pages(void)
2432 {
2433 	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2434 }
2435 
show_node(struct zone * zone)2436 static inline void show_node(struct zone *zone)
2437 {
2438 	if (NUMA_BUILD)
2439 		printk("Node %d ", zone_to_nid(zone));
2440 }
2441 
si_meminfo(struct sysinfo * val)2442 void si_meminfo(struct sysinfo *val)
2443 {
2444 	val->totalram = totalram_pages;
2445 	val->sharedram = 0;
2446 	val->freeram = global_page_state(NR_FREE_PAGES);
2447 	val->bufferram = nr_blockdev_pages();
2448 	val->totalhigh = totalhigh_pages;
2449 	val->freehigh = nr_free_highpages();
2450 	val->mem_unit = PAGE_SIZE;
2451 }
2452 
2453 EXPORT_SYMBOL(si_meminfo);
2454 
2455 #ifdef CONFIG_NUMA
si_meminfo_node(struct sysinfo * val,int nid)2456 void si_meminfo_node(struct sysinfo *val, int nid)
2457 {
2458 	pg_data_t *pgdat = NODE_DATA(nid);
2459 
2460 	val->totalram = pgdat->node_present_pages;
2461 	val->freeram = node_page_state(nid, NR_FREE_PAGES);
2462 #ifdef CONFIG_HIGHMEM
2463 	val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
2464 	val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2465 			NR_FREE_PAGES);
2466 #else
2467 	val->totalhigh = 0;
2468 	val->freehigh = 0;
2469 #endif
2470 	val->mem_unit = PAGE_SIZE;
2471 }
2472 #endif
2473 
2474 /*
2475  * Determine whether the zone's node should be displayed or not, depending on
2476  * whether SHOW_MEM_FILTER_NODES was passed to __show_free_areas().
2477  */
skip_free_areas_zone(unsigned int flags,const struct zone * zone)2478 static bool skip_free_areas_zone(unsigned int flags, const struct zone *zone)
2479 {
2480 	bool ret = false;
2481 
2482 	if (!(flags & SHOW_MEM_FILTER_NODES))
2483 		goto out;
2484 
2485 	get_mems_allowed();
2486 	ret = !node_isset(zone->zone_pgdat->node_id,
2487 				cpuset_current_mems_allowed);
2488 	put_mems_allowed();
2489 out:
2490 	return ret;
2491 }
2492 
2493 #define K(x) ((x) << (PAGE_SHIFT-10))
2494 
2495 /*
2496  * Show free area list (used inside shift_scroll-lock stuff)
2497  * We also calculate the percentage fragmentation. We do this by counting the
2498  * memory on each free list with the exception of the first item on the list.
2499  * Suppresses nodes that are not allowed by current's cpuset if
2500  * SHOW_MEM_FILTER_NODES is passed.
2501  */
__show_free_areas(unsigned int filter)2502 void __show_free_areas(unsigned int filter)
2503 {
2504 	int cpu;
2505 	struct zone *zone;
2506 
2507 	for_each_populated_zone(zone) {
2508 		if (skip_free_areas_zone(filter, zone))
2509 			continue;
2510 		show_node(zone);
2511 		printk("%s per-cpu:\n", zone->name);
2512 
2513 		for_each_online_cpu(cpu) {
2514 			struct per_cpu_pageset *pageset;
2515 
2516 			pageset = per_cpu_ptr(zone->pageset, cpu);
2517 
2518 			printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
2519 			       cpu, pageset->pcp.high,
2520 			       pageset->pcp.batch, pageset->pcp.count);
2521 		}
2522 	}
2523 
2524 	printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
2525 		" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
2526 		" unevictable:%lu"
2527 		" dirty:%lu writeback:%lu unstable:%lu\n"
2528 		" free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
2529 		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
2530 		global_page_state(NR_ACTIVE_ANON),
2531 		global_page_state(NR_INACTIVE_ANON),
2532 		global_page_state(NR_ISOLATED_ANON),
2533 		global_page_state(NR_ACTIVE_FILE),
2534 		global_page_state(NR_INACTIVE_FILE),
2535 		global_page_state(NR_ISOLATED_FILE),
2536 		global_page_state(NR_UNEVICTABLE),
2537 		global_page_state(NR_FILE_DIRTY),
2538 		global_page_state(NR_WRITEBACK),
2539 		global_page_state(NR_UNSTABLE_NFS),
2540 		global_page_state(NR_FREE_PAGES),
2541 		global_page_state(NR_SLAB_RECLAIMABLE),
2542 		global_page_state(NR_SLAB_UNRECLAIMABLE),
2543 		global_page_state(NR_FILE_MAPPED),
2544 		global_page_state(NR_SHMEM),
2545 		global_page_state(NR_PAGETABLE),
2546 		global_page_state(NR_BOUNCE));
2547 
2548 	for_each_populated_zone(zone) {
2549 		int i;
2550 
2551 		if (skip_free_areas_zone(filter, zone))
2552 			continue;
2553 		show_node(zone);
2554 		printk("%s"
2555 			" free:%lukB"
2556 			" min:%lukB"
2557 			" low:%lukB"
2558 			" high:%lukB"
2559 			" active_anon:%lukB"
2560 			" inactive_anon:%lukB"
2561 			" active_file:%lukB"
2562 			" inactive_file:%lukB"
2563 			" unevictable:%lukB"
2564 			" isolated(anon):%lukB"
2565 			" isolated(file):%lukB"
2566 			" present:%lukB"
2567 			" mlocked:%lukB"
2568 			" dirty:%lukB"
2569 			" writeback:%lukB"
2570 			" mapped:%lukB"
2571 			" shmem:%lukB"
2572 			" slab_reclaimable:%lukB"
2573 			" slab_unreclaimable:%lukB"
2574 			" kernel_stack:%lukB"
2575 			" pagetables:%lukB"
2576 			" unstable:%lukB"
2577 			" bounce:%lukB"
2578 			" writeback_tmp:%lukB"
2579 			" pages_scanned:%lu"
2580 			" all_unreclaimable? %s"
2581 			"\n",
2582 			zone->name,
2583 			K(zone_page_state(zone, NR_FREE_PAGES)),
2584 			K(min_wmark_pages(zone)),
2585 			K(low_wmark_pages(zone)),
2586 			K(high_wmark_pages(zone)),
2587 			K(zone_page_state(zone, NR_ACTIVE_ANON)),
2588 			K(zone_page_state(zone, NR_INACTIVE_ANON)),
2589 			K(zone_page_state(zone, NR_ACTIVE_FILE)),
2590 			K(zone_page_state(zone, NR_INACTIVE_FILE)),
2591 			K(zone_page_state(zone, NR_UNEVICTABLE)),
2592 			K(zone_page_state(zone, NR_ISOLATED_ANON)),
2593 			K(zone_page_state(zone, NR_ISOLATED_FILE)),
2594 			K(zone->present_pages),
2595 			K(zone_page_state(zone, NR_MLOCK)),
2596 			K(zone_page_state(zone, NR_FILE_DIRTY)),
2597 			K(zone_page_state(zone, NR_WRITEBACK)),
2598 			K(zone_page_state(zone, NR_FILE_MAPPED)),
2599 			K(zone_page_state(zone, NR_SHMEM)),
2600 			K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
2601 			K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
2602 			zone_page_state(zone, NR_KERNEL_STACK) *
2603 				THREAD_SIZE / 1024,
2604 			K(zone_page_state(zone, NR_PAGETABLE)),
2605 			K(zone_page_state(zone, NR_UNSTABLE_NFS)),
2606 			K(zone_page_state(zone, NR_BOUNCE)),
2607 			K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
2608 			zone->pages_scanned,
2609 			(zone->all_unreclaimable ? "yes" : "no")
2610 			);
2611 		printk("lowmem_reserve[]:");
2612 		for (i = 0; i < MAX_NR_ZONES; i++)
2613 			printk(" %lu", zone->lowmem_reserve[i]);
2614 		printk("\n");
2615 	}
2616 
2617 	for_each_populated_zone(zone) {
2618  		unsigned long nr[MAX_ORDER], flags, order, total = 0;
2619 
2620 		if (skip_free_areas_zone(filter, zone))
2621 			continue;
2622 		show_node(zone);
2623 		printk("%s: ", zone->name);
2624 
2625 		spin_lock_irqsave(&zone->lock, flags);
2626 		for (order = 0; order < MAX_ORDER; order++) {
2627 			nr[order] = zone->free_area[order].nr_free;
2628 			total += nr[order] << order;
2629 		}
2630 		spin_unlock_irqrestore(&zone->lock, flags);
2631 		for (order = 0; order < MAX_ORDER; order++)
2632 			printk("%lu*%lukB ", nr[order], K(1UL) << order);
2633 		printk("= %lukB\n", K(total));
2634 	}
2635 
2636 	printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
2637 
2638 	show_swap_cache_info();
2639 }
2640 
show_free_areas(void)2641 void show_free_areas(void)
2642 {
2643 	__show_free_areas(0);
2644 }
2645 
zoneref_set_zone(struct zone * zone,struct zoneref * zoneref)2646 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
2647 {
2648 	zoneref->zone = zone;
2649 	zoneref->zone_idx = zone_idx(zone);
2650 }
2651 
2652 /*
2653  * Builds allocation fallback zone lists.
2654  *
2655  * Add all populated zones of a node to the zonelist.
2656  */
build_zonelists_node(pg_data_t * pgdat,struct zonelist * zonelist,int nr_zones,enum zone_type zone_type)2657 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
2658 				int nr_zones, enum zone_type zone_type)
2659 {
2660 	struct zone *zone;
2661 
2662 	BUG_ON(zone_type >= MAX_NR_ZONES);
2663 	zone_type++;
2664 
2665 	do {
2666 		zone_type--;
2667 		zone = pgdat->node_zones + zone_type;
2668 		if (populated_zone(zone)) {
2669 			zoneref_set_zone(zone,
2670 				&zonelist->_zonerefs[nr_zones++]);
2671 			check_highest_zone(zone_type);
2672 		}
2673 
2674 	} while (zone_type);
2675 	return nr_zones;
2676 }
2677 
2678 
2679 /*
2680  *  zonelist_order:
2681  *  0 = automatic detection of better ordering.
2682  *  1 = order by ([node] distance, -zonetype)
2683  *  2 = order by (-zonetype, [node] distance)
2684  *
2685  *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
2686  *  the same zonelist. So only NUMA can configure this param.
2687  */
2688 #define ZONELIST_ORDER_DEFAULT  0
2689 #define ZONELIST_ORDER_NODE     1
2690 #define ZONELIST_ORDER_ZONE     2
2691 
2692 /* zonelist order in the kernel.
2693  * set_zonelist_order() will set this to NODE or ZONE.
2694  */
2695 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
2696 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
2697 
2698 
2699 #ifdef CONFIG_NUMA
2700 /* The value user specified ....changed by config */
2701 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2702 /* string for sysctl */
2703 #define NUMA_ZONELIST_ORDER_LEN	16
2704 char numa_zonelist_order[16] = "default";
2705 
2706 /*
2707  * interface for configure zonelist ordering.
2708  * command line option "numa_zonelist_order"
2709  *	= "[dD]efault	- default, automatic configuration.
2710  *	= "[nN]ode 	- order by node locality, then by zone within node
2711  *	= "[zZ]one      - order by zone, then by locality within zone
2712  */
2713 
__parse_numa_zonelist_order(char * s)2714 static int __parse_numa_zonelist_order(char *s)
2715 {
2716 	if (*s == 'd' || *s == 'D') {
2717 		user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2718 	} else if (*s == 'n' || *s == 'N') {
2719 		user_zonelist_order = ZONELIST_ORDER_NODE;
2720 	} else if (*s == 'z' || *s == 'Z') {
2721 		user_zonelist_order = ZONELIST_ORDER_ZONE;
2722 	} else {
2723 		printk(KERN_WARNING
2724 			"Ignoring invalid numa_zonelist_order value:  "
2725 			"%s\n", s);
2726 		return -EINVAL;
2727 	}
2728 	return 0;
2729 }
2730 
setup_numa_zonelist_order(char * s)2731 static __init int setup_numa_zonelist_order(char *s)
2732 {
2733 	int ret;
2734 
2735 	if (!s)
2736 		return 0;
2737 
2738 	ret = __parse_numa_zonelist_order(s);
2739 	if (ret == 0)
2740 		strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
2741 
2742 	return ret;
2743 }
2744 early_param("numa_zonelist_order", setup_numa_zonelist_order);
2745 
2746 /*
2747  * sysctl handler for numa_zonelist_order
2748  */
numa_zonelist_order_handler(ctl_table * table,int write,void __user * buffer,size_t * length,loff_t * ppos)2749 int numa_zonelist_order_handler(ctl_table *table, int write,
2750 		void __user *buffer, size_t *length,
2751 		loff_t *ppos)
2752 {
2753 	char saved_string[NUMA_ZONELIST_ORDER_LEN];
2754 	int ret;
2755 	static DEFINE_MUTEX(zl_order_mutex);
2756 
2757 	mutex_lock(&zl_order_mutex);
2758 	if (write)
2759 		strcpy(saved_string, (char*)table->data);
2760 	ret = proc_dostring(table, write, buffer, length, ppos);
2761 	if (ret)
2762 		goto out;
2763 	if (write) {
2764 		int oldval = user_zonelist_order;
2765 		if (__parse_numa_zonelist_order((char*)table->data)) {
2766 			/*
2767 			 * bogus value.  restore saved string
2768 			 */
2769 			strncpy((char*)table->data, saved_string,
2770 				NUMA_ZONELIST_ORDER_LEN);
2771 			user_zonelist_order = oldval;
2772 		} else if (oldval != user_zonelist_order) {
2773 			mutex_lock(&zonelists_mutex);
2774 			build_all_zonelists(NULL);
2775 			mutex_unlock(&zonelists_mutex);
2776 		}
2777 	}
2778 out:
2779 	mutex_unlock(&zl_order_mutex);
2780 	return ret;
2781 }
2782 
2783 
2784 #define MAX_NODE_LOAD (nr_online_nodes)
2785 static int node_load[MAX_NUMNODES];
2786 
2787 /**
2788  * find_next_best_node - find the next node that should appear in a given node's fallback list
2789  * @node: node whose fallback list we're appending
2790  * @used_node_mask: nodemask_t of already used nodes
2791  *
2792  * We use a number of factors to determine which is the next node that should
2793  * appear on a given node's fallback list.  The node should not have appeared
2794  * already in @node's fallback list, and it should be the next closest node
2795  * according to the distance array (which contains arbitrary distance values
2796  * from each node to each node in the system), and should also prefer nodes
2797  * with no CPUs, since presumably they'll have very little allocation pressure
2798  * on them otherwise.
2799  * It returns -1 if no node is found.
2800  */
find_next_best_node(int node,nodemask_t * used_node_mask)2801 static int find_next_best_node(int node, nodemask_t *used_node_mask)
2802 {
2803 	int n, val;
2804 	int min_val = INT_MAX;
2805 	int best_node = -1;
2806 	const struct cpumask *tmp = cpumask_of_node(0);
2807 
2808 	/* Use the local node if we haven't already */
2809 	if (!node_isset(node, *used_node_mask)) {
2810 		node_set(node, *used_node_mask);
2811 		return node;
2812 	}
2813 
2814 	for_each_node_state(n, N_HIGH_MEMORY) {
2815 
2816 		/* Don't want a node to appear more than once */
2817 		if (node_isset(n, *used_node_mask))
2818 			continue;
2819 
2820 		/* Use the distance array to find the distance */
2821 		val = node_distance(node, n);
2822 
2823 		/* Penalize nodes under us ("prefer the next node") */
2824 		val += (n < node);
2825 
2826 		/* Give preference to headless and unused nodes */
2827 		tmp = cpumask_of_node(n);
2828 		if (!cpumask_empty(tmp))
2829 			val += PENALTY_FOR_NODE_WITH_CPUS;
2830 
2831 		/* Slight preference for less loaded node */
2832 		val *= (MAX_NODE_LOAD*MAX_NUMNODES);
2833 		val += node_load[n];
2834 
2835 		if (val < min_val) {
2836 			min_val = val;
2837 			best_node = n;
2838 		}
2839 	}
2840 
2841 	if (best_node >= 0)
2842 		node_set(best_node, *used_node_mask);
2843 
2844 	return best_node;
2845 }
2846 
2847 
2848 /*
2849  * Build zonelists ordered by node and zones within node.
2850  * This results in maximum locality--normal zone overflows into local
2851  * DMA zone, if any--but risks exhausting DMA zone.
2852  */
build_zonelists_in_node_order(pg_data_t * pgdat,int node)2853 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
2854 {
2855 	int j;
2856 	struct zonelist *zonelist;
2857 
2858 	zonelist = &pgdat->node_zonelists[0];
2859 	for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
2860 		;
2861 	j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2862 							MAX_NR_ZONES - 1);
2863 	zonelist->_zonerefs[j].zone = NULL;
2864 	zonelist->_zonerefs[j].zone_idx = 0;
2865 }
2866 
2867 /*
2868  * Build gfp_thisnode zonelists
2869  */
build_thisnode_zonelists(pg_data_t * pgdat)2870 static void build_thisnode_zonelists(pg_data_t *pgdat)
2871 {
2872 	int j;
2873 	struct zonelist *zonelist;
2874 
2875 	zonelist = &pgdat->node_zonelists[1];
2876 	j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2877 	zonelist->_zonerefs[j].zone = NULL;
2878 	zonelist->_zonerefs[j].zone_idx = 0;
2879 }
2880 
2881 /*
2882  * Build zonelists ordered by zone and nodes within zones.
2883  * This results in conserving DMA zone[s] until all Normal memory is
2884  * exhausted, but results in overflowing to remote node while memory
2885  * may still exist in local DMA zone.
2886  */
2887 static int node_order[MAX_NUMNODES];
2888 
build_zonelists_in_zone_order(pg_data_t * pgdat,int nr_nodes)2889 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
2890 {
2891 	int pos, j, node;
2892 	int zone_type;		/* needs to be signed */
2893 	struct zone *z;
2894 	struct zonelist *zonelist;
2895 
2896 	zonelist = &pgdat->node_zonelists[0];
2897 	pos = 0;
2898 	for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
2899 		for (j = 0; j < nr_nodes; j++) {
2900 			node = node_order[j];
2901 			z = &NODE_DATA(node)->node_zones[zone_type];
2902 			if (populated_zone(z)) {
2903 				zoneref_set_zone(z,
2904 					&zonelist->_zonerefs[pos++]);
2905 				check_highest_zone(zone_type);
2906 			}
2907 		}
2908 	}
2909 	zonelist->_zonerefs[pos].zone = NULL;
2910 	zonelist->_zonerefs[pos].zone_idx = 0;
2911 }
2912 
default_zonelist_order(void)2913 static int default_zonelist_order(void)
2914 {
2915 	int nid, zone_type;
2916 	unsigned long low_kmem_size,total_size;
2917 	struct zone *z;
2918 	int average_size;
2919 	/*
2920          * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
2921 	 * If they are really small and used heavily, the system can fall
2922 	 * into OOM very easily.
2923 	 * This function detect ZONE_DMA/DMA32 size and configures zone order.
2924 	 */
2925 	/* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
2926 	low_kmem_size = 0;
2927 	total_size = 0;
2928 	for_each_online_node(nid) {
2929 		for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2930 			z = &NODE_DATA(nid)->node_zones[zone_type];
2931 			if (populated_zone(z)) {
2932 				if (zone_type < ZONE_NORMAL)
2933 					low_kmem_size += z->present_pages;
2934 				total_size += z->present_pages;
2935 			} else if (zone_type == ZONE_NORMAL) {
2936 				/*
2937 				 * If any node has only lowmem, then node order
2938 				 * is preferred to allow kernel allocations
2939 				 * locally; otherwise, they can easily infringe
2940 				 * on other nodes when there is an abundance of
2941 				 * lowmem available to allocate from.
2942 				 */
2943 				return ZONELIST_ORDER_NODE;
2944 			}
2945 		}
2946 	}
2947 	if (!low_kmem_size ||  /* there are no DMA area. */
2948 	    low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
2949 		return ZONELIST_ORDER_NODE;
2950 	/*
2951 	 * look into each node's config.
2952   	 * If there is a node whose DMA/DMA32 memory is very big area on
2953  	 * local memory, NODE_ORDER may be suitable.
2954          */
2955 	average_size = total_size /
2956 				(nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
2957 	for_each_online_node(nid) {
2958 		low_kmem_size = 0;
2959 		total_size = 0;
2960 		for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2961 			z = &NODE_DATA(nid)->node_zones[zone_type];
2962 			if (populated_zone(z)) {
2963 				if (zone_type < ZONE_NORMAL)
2964 					low_kmem_size += z->present_pages;
2965 				total_size += z->present_pages;
2966 			}
2967 		}
2968 		if (low_kmem_size &&
2969 		    total_size > average_size && /* ignore small node */
2970 		    low_kmem_size > total_size * 70/100)
2971 			return ZONELIST_ORDER_NODE;
2972 	}
2973 	return ZONELIST_ORDER_ZONE;
2974 }
2975 
set_zonelist_order(void)2976 static void set_zonelist_order(void)
2977 {
2978 	if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
2979 		current_zonelist_order = default_zonelist_order();
2980 	else
2981 		current_zonelist_order = user_zonelist_order;
2982 }
2983 
build_zonelists(pg_data_t * pgdat)2984 static void build_zonelists(pg_data_t *pgdat)
2985 {
2986 	int j, node, load;
2987 	enum zone_type i;
2988 	nodemask_t used_mask;
2989 	int local_node, prev_node;
2990 	struct zonelist *zonelist;
2991 	int order = current_zonelist_order;
2992 
2993 	/* initialize zonelists */
2994 	for (i = 0; i < MAX_ZONELISTS; i++) {
2995 		zonelist = pgdat->node_zonelists + i;
2996 		zonelist->_zonerefs[0].zone = NULL;
2997 		zonelist->_zonerefs[0].zone_idx = 0;
2998 	}
2999 
3000 	/* NUMA-aware ordering of nodes */
3001 	local_node = pgdat->node_id;
3002 	load = nr_online_nodes;
3003 	prev_node = local_node;
3004 	nodes_clear(used_mask);
3005 
3006 	memset(node_order, 0, sizeof(node_order));
3007 	j = 0;
3008 
3009 	while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3010 		int distance = node_distance(local_node, node);
3011 
3012 		/*
3013 		 * If another node is sufficiently far away then it is better
3014 		 * to reclaim pages in a zone before going off node.
3015 		 */
3016 		if (distance > RECLAIM_DISTANCE)
3017 			zone_reclaim_mode = 1;
3018 
3019 		/*
3020 		 * We don't want to pressure a particular node.
3021 		 * So adding penalty to the first node in same
3022 		 * distance group to make it round-robin.
3023 		 */
3024 		if (distance != node_distance(local_node, prev_node))
3025 			node_load[node] = load;
3026 
3027 		prev_node = node;
3028 		load--;
3029 		if (order == ZONELIST_ORDER_NODE)
3030 			build_zonelists_in_node_order(pgdat, node);
3031 		else
3032 			node_order[j++] = node;	/* remember order */
3033 	}
3034 
3035 	if (order == ZONELIST_ORDER_ZONE) {
3036 		/* calculate node order -- i.e., DMA last! */
3037 		build_zonelists_in_zone_order(pgdat, j);
3038 	}
3039 
3040 	build_thisnode_zonelists(pgdat);
3041 }
3042 
3043 /* Construct the zonelist performance cache - see further mmzone.h */
build_zonelist_cache(pg_data_t * pgdat)3044 static void build_zonelist_cache(pg_data_t *pgdat)
3045 {
3046 	struct zonelist *zonelist;
3047 	struct zonelist_cache *zlc;
3048 	struct zoneref *z;
3049 
3050 	zonelist = &pgdat->node_zonelists[0];
3051 	zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3052 	bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3053 	for (z = zonelist->_zonerefs; z->zone; z++)
3054 		zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3055 }
3056 
3057 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3058 /*
3059  * Return node id of node used for "local" allocations.
3060  * I.e., first node id of first zone in arg node's generic zonelist.
3061  * Used for initializing percpu 'numa_mem', which is used primarily
3062  * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3063  */
local_memory_node(int node)3064 int local_memory_node(int node)
3065 {
3066 	struct zone *zone;
3067 
3068 	(void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3069 				   gfp_zone(GFP_KERNEL),
3070 				   NULL,
3071 				   &zone);
3072 	return zone->node;
3073 }
3074 #endif
3075 
3076 #else	/* CONFIG_NUMA */
3077 
set_zonelist_order(void)3078 static void set_zonelist_order(void)
3079 {
3080 	current_zonelist_order = ZONELIST_ORDER_ZONE;
3081 }
3082 
build_zonelists(pg_data_t * pgdat)3083 static void build_zonelists(pg_data_t *pgdat)
3084 {
3085 	int node, local_node;
3086 	enum zone_type j;
3087 	struct zonelist *zonelist;
3088 
3089 	local_node = pgdat->node_id;
3090 
3091 	zonelist = &pgdat->node_zonelists[0];
3092 	j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
3093 
3094 	/*
3095 	 * Now we build the zonelist so that it contains the zones
3096 	 * of all the other nodes.
3097 	 * We don't want to pressure a particular node, so when
3098 	 * building the zones for node N, we make sure that the
3099 	 * zones coming right after the local ones are those from
3100 	 * node N+1 (modulo N)
3101 	 */
3102 	for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3103 		if (!node_online(node))
3104 			continue;
3105 		j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3106 							MAX_NR_ZONES - 1);
3107 	}
3108 	for (node = 0; node < local_node; node++) {
3109 		if (!node_online(node))
3110 			continue;
3111 		j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3112 							MAX_NR_ZONES - 1);
3113 	}
3114 
3115 	zonelist->_zonerefs[j].zone = NULL;
3116 	zonelist->_zonerefs[j].zone_idx = 0;
3117 }
3118 
3119 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
build_zonelist_cache(pg_data_t * pgdat)3120 static void build_zonelist_cache(pg_data_t *pgdat)
3121 {
3122 	pgdat->node_zonelists[0].zlcache_ptr = NULL;
3123 }
3124 
3125 #endif	/* CONFIG_NUMA */
3126 
3127 /*
3128  * Boot pageset table. One per cpu which is going to be used for all
3129  * zones and all nodes. The parameters will be set in such a way
3130  * that an item put on a list will immediately be handed over to
3131  * the buddy list. This is safe since pageset manipulation is done
3132  * with interrupts disabled.
3133  *
3134  * The boot_pagesets must be kept even after bootup is complete for
3135  * unused processors and/or zones. They do play a role for bootstrapping
3136  * hotplugged processors.
3137  *
3138  * zoneinfo_show() and maybe other functions do
3139  * not check if the processor is online before following the pageset pointer.
3140  * Other parts of the kernel may not check if the zone is available.
3141  */
3142 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3143 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3144 static void setup_zone_pageset(struct zone *zone);
3145 
3146 /*
3147  * Global mutex to protect against size modification of zonelists
3148  * as well as to serialize pageset setup for the new populated zone.
3149  */
3150 DEFINE_MUTEX(zonelists_mutex);
3151 
3152 /* return values int ....just for stop_machine() */
__build_all_zonelists(void * data)3153 static __init_refok int __build_all_zonelists(void *data)
3154 {
3155 	int nid;
3156 	int cpu;
3157 
3158 #ifdef CONFIG_NUMA
3159 	memset(node_load, 0, sizeof(node_load));
3160 #endif
3161 	for_each_online_node(nid) {
3162 		pg_data_t *pgdat = NODE_DATA(nid);
3163 
3164 		build_zonelists(pgdat);
3165 		build_zonelist_cache(pgdat);
3166 	}
3167 
3168 	/*
3169 	 * Initialize the boot_pagesets that are going to be used
3170 	 * for bootstrapping processors. The real pagesets for
3171 	 * each zone will be allocated later when the per cpu
3172 	 * allocator is available.
3173 	 *
3174 	 * boot_pagesets are used also for bootstrapping offline
3175 	 * cpus if the system is already booted because the pagesets
3176 	 * are needed to initialize allocators on a specific cpu too.
3177 	 * F.e. the percpu allocator needs the page allocator which
3178 	 * needs the percpu allocator in order to allocate its pagesets
3179 	 * (a chicken-egg dilemma).
3180 	 */
3181 	for_each_possible_cpu(cpu) {
3182 		setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3183 
3184 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3185 		/*
3186 		 * We now know the "local memory node" for each node--
3187 		 * i.e., the node of the first zone in the generic zonelist.
3188 		 * Set up numa_mem percpu variable for on-line cpus.  During
3189 		 * boot, only the boot cpu should be on-line;  we'll init the
3190 		 * secondary cpus' numa_mem as they come on-line.  During
3191 		 * node/memory hotplug, we'll fixup all on-line cpus.
3192 		 */
3193 		if (cpu_online(cpu))
3194 			set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3195 #endif
3196 	}
3197 
3198 	return 0;
3199 }
3200 
3201 /*
3202  * Called with zonelists_mutex held always
3203  * unless system_state == SYSTEM_BOOTING.
3204  */
build_all_zonelists(void * data)3205 void __ref build_all_zonelists(void *data)
3206 {
3207 	set_zonelist_order();
3208 
3209 	if (system_state == SYSTEM_BOOTING) {
3210 		__build_all_zonelists(NULL);
3211 		mminit_verify_zonelist();
3212 		cpuset_init_current_mems_allowed();
3213 	} else {
3214 		/* we have to stop all cpus to guarantee there is no user
3215 		   of zonelist */
3216 #ifdef CONFIG_MEMORY_HOTPLUG
3217 		if (data)
3218 			setup_zone_pageset((struct zone *)data);
3219 #endif
3220 		stop_machine(__build_all_zonelists, NULL, NULL);
3221 		/* cpuset refresh routine should be here */
3222 	}
3223 	vm_total_pages = nr_free_pagecache_pages();
3224 	/*
3225 	 * Disable grouping by mobility if the number of pages in the
3226 	 * system is too low to allow the mechanism to work. It would be
3227 	 * more accurate, but expensive to check per-zone. This check is
3228 	 * made on memory-hotadd so a system can start with mobility
3229 	 * disabled and enable it later
3230 	 */
3231 	if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3232 		page_group_by_mobility_disabled = 1;
3233 	else
3234 		page_group_by_mobility_disabled = 0;
3235 
3236 	printk("Built %i zonelists in %s order, mobility grouping %s.  "
3237 		"Total pages: %ld\n",
3238 			nr_online_nodes,
3239 			zonelist_order_name[current_zonelist_order],
3240 			page_group_by_mobility_disabled ? "off" : "on",
3241 			vm_total_pages);
3242 #ifdef CONFIG_NUMA
3243 	printk("Policy zone: %s\n", zone_names[policy_zone]);
3244 #endif
3245 }
3246 
3247 /*
3248  * Helper functions to size the waitqueue hash table.
3249  * Essentially these want to choose hash table sizes sufficiently
3250  * large so that collisions trying to wait on pages are rare.
3251  * But in fact, the number of active page waitqueues on typical
3252  * systems is ridiculously low, less than 200. So this is even
3253  * conservative, even though it seems large.
3254  *
3255  * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3256  * waitqueues, i.e. the size of the waitq table given the number of pages.
3257  */
3258 #define PAGES_PER_WAITQUEUE	256
3259 
3260 #ifndef CONFIG_MEMORY_HOTPLUG
wait_table_hash_nr_entries(unsigned long pages)3261 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3262 {
3263 	unsigned long size = 1;
3264 
3265 	pages /= PAGES_PER_WAITQUEUE;
3266 
3267 	while (size < pages)
3268 		size <<= 1;
3269 
3270 	/*
3271 	 * Once we have dozens or even hundreds of threads sleeping
3272 	 * on IO we've got bigger problems than wait queue collision.
3273 	 * Limit the size of the wait table to a reasonable size.
3274 	 */
3275 	size = min(size, 4096UL);
3276 
3277 	return max(size, 4UL);
3278 }
3279 #else
3280 /*
3281  * A zone's size might be changed by hot-add, so it is not possible to determine
3282  * a suitable size for its wait_table.  So we use the maximum size now.
3283  *
3284  * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
3285  *
3286  *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
3287  *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3288  *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
3289  *
3290  * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3291  * or more by the traditional way. (See above).  It equals:
3292  *
3293  *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
3294  *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
3295  *    powerpc (64K page size)             : =  (32G +16M)byte.
3296  */
wait_table_hash_nr_entries(unsigned long pages)3297 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3298 {
3299 	return 4096UL;
3300 }
3301 #endif
3302 
3303 /*
3304  * This is an integer logarithm so that shifts can be used later
3305  * to extract the more random high bits from the multiplicative
3306  * hash function before the remainder is taken.
3307  */
wait_table_bits(unsigned long size)3308 static inline unsigned long wait_table_bits(unsigned long size)
3309 {
3310 	return ffz(~size);
3311 }
3312 
3313 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3314 
3315 /*
3316  * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3317  * of blocks reserved is based on min_wmark_pages(zone). The memory within
3318  * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3319  * higher will lead to a bigger reserve which will get freed as contiguous
3320  * blocks as reclaim kicks in
3321  */
setup_zone_migrate_reserve(struct zone * zone)3322 static void setup_zone_migrate_reserve(struct zone *zone)
3323 {
3324 	unsigned long start_pfn, pfn, end_pfn;
3325 	struct page *page;
3326 	unsigned long block_migratetype;
3327 	int reserve;
3328 
3329 	/* Get the start pfn, end pfn and the number of blocks to reserve */
3330 	start_pfn = zone->zone_start_pfn;
3331 	end_pfn = start_pfn + zone->spanned_pages;
3332 	reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3333 							pageblock_order;
3334 
3335 	/*
3336 	 * Reserve blocks are generally in place to help high-order atomic
3337 	 * allocations that are short-lived. A min_free_kbytes value that
3338 	 * would result in more than 2 reserve blocks for atomic allocations
3339 	 * is assumed to be in place to help anti-fragmentation for the
3340 	 * future allocation of hugepages at runtime.
3341 	 */
3342 	reserve = min(2, reserve);
3343 
3344 	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3345 		if (!pfn_valid(pfn))
3346 			continue;
3347 		page = pfn_to_page(pfn);
3348 
3349 		/* Watch out for overlapping nodes */
3350 		if (page_to_nid(page) != zone_to_nid(zone))
3351 			continue;
3352 
3353 		/* Blocks with reserved pages will never free, skip them. */
3354 		if (PageReserved(page))
3355 			continue;
3356 
3357 		block_migratetype = get_pageblock_migratetype(page);
3358 
3359 		/* If this block is reserved, account for it */
3360 		if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
3361 			reserve--;
3362 			continue;
3363 		}
3364 
3365 		/* Suitable for reserving if this block is movable */
3366 		if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
3367 			set_pageblock_migratetype(page, MIGRATE_RESERVE);
3368 			move_freepages_block(zone, page, MIGRATE_RESERVE);
3369 			reserve--;
3370 			continue;
3371 		}
3372 
3373 		/*
3374 		 * If the reserve is met and this is a previous reserved block,
3375 		 * take it back
3376 		 */
3377 		if (block_migratetype == MIGRATE_RESERVE) {
3378 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3379 			move_freepages_block(zone, page, MIGRATE_MOVABLE);
3380 		}
3381 	}
3382 }
3383 
3384 /*
3385  * Initially all pages are reserved - free ones are freed
3386  * up by free_all_bootmem() once the early boot process is
3387  * done. Non-atomic initialization, single-pass.
3388  */
memmap_init_zone(unsigned long size,int nid,unsigned long zone,unsigned long start_pfn,enum memmap_context context)3389 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3390 		unsigned long start_pfn, enum memmap_context context)
3391 {
3392 	struct page *page;
3393 	unsigned long end_pfn = start_pfn + size;
3394 	unsigned long pfn;
3395 	struct zone *z;
3396 
3397 	if (highest_memmap_pfn < end_pfn - 1)
3398 		highest_memmap_pfn = end_pfn - 1;
3399 
3400 	z = &NODE_DATA(nid)->node_zones[zone];
3401 	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3402 		/*
3403 		 * There can be holes in boot-time mem_map[]s
3404 		 * handed to this function.  They do not
3405 		 * exist on hotplugged memory.
3406 		 */
3407 		if (context == MEMMAP_EARLY) {
3408 			if (!early_pfn_valid(pfn))
3409 				continue;
3410 			if (!early_pfn_in_nid(pfn, nid))
3411 				continue;
3412 		}
3413 		page = pfn_to_page(pfn);
3414 		set_page_links(page, zone, nid, pfn);
3415 		mminit_verify_page_links(page, zone, nid, pfn);
3416 		init_page_count(page);
3417 		reset_page_mapcount(page);
3418 		SetPageReserved(page);
3419 		/*
3420 		 * Mark the block movable so that blocks are reserved for
3421 		 * movable at startup. This will force kernel allocations
3422 		 * to reserve their blocks rather than leaking throughout
3423 		 * the address space during boot when many long-lived
3424 		 * kernel allocations are made. Later some blocks near
3425 		 * the start are marked MIGRATE_RESERVE by
3426 		 * setup_zone_migrate_reserve()
3427 		 *
3428 		 * bitmap is created for zone's valid pfn range. but memmap
3429 		 * can be created for invalid pages (for alignment)
3430 		 * check here not to call set_pageblock_migratetype() against
3431 		 * pfn out of zone.
3432 		 */
3433 		if ((z->zone_start_pfn <= pfn)
3434 		    && (pfn < z->zone_start_pfn + z->spanned_pages)
3435 		    && !(pfn & (pageblock_nr_pages - 1)))
3436 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3437 
3438 		INIT_LIST_HEAD(&page->lru);
3439 #ifdef WANT_PAGE_VIRTUAL
3440 		/* The shift won't overflow because ZONE_NORMAL is below 4G. */
3441 		if (!is_highmem_idx(zone))
3442 			set_page_address(page, __va(pfn << PAGE_SHIFT));
3443 #endif
3444 	}
3445 }
3446 
zone_init_free_lists(struct zone * zone)3447 static void __meminit zone_init_free_lists(struct zone *zone)
3448 {
3449 	int order, t;
3450 	for_each_migratetype_order(order, t) {
3451 		INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3452 		zone->free_area[order].nr_free = 0;
3453 	}
3454 }
3455 
3456 #ifndef __HAVE_ARCH_MEMMAP_INIT
3457 #define memmap_init(size, nid, zone, start_pfn) \
3458 	memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3459 #endif
3460 
zone_batchsize(struct zone * zone)3461 static int zone_batchsize(struct zone *zone)
3462 {
3463 #ifdef CONFIG_MMU
3464 	int batch;
3465 
3466 	/*
3467 	 * The per-cpu-pages pools are set to around 1000th of the
3468 	 * size of the zone.  But no more than 1/2 of a meg.
3469 	 *
3470 	 * OK, so we don't know how big the cache is.  So guess.
3471 	 */
3472 	batch = zone->present_pages / 1024;
3473 	if (batch * PAGE_SIZE > 512 * 1024)
3474 		batch = (512 * 1024) / PAGE_SIZE;
3475 	batch /= 4;		/* We effectively *= 4 below */
3476 	if (batch < 1)
3477 		batch = 1;
3478 
3479 	/*
3480 	 * Clamp the batch to a 2^n - 1 value. Having a power
3481 	 * of 2 value was found to be more likely to have
3482 	 * suboptimal cache aliasing properties in some cases.
3483 	 *
3484 	 * For example if 2 tasks are alternately allocating
3485 	 * batches of pages, one task can end up with a lot
3486 	 * of pages of one half of the possible page colors
3487 	 * and the other with pages of the other colors.
3488 	 */
3489 	batch = rounddown_pow_of_two(batch + batch/2) - 1;
3490 
3491 	return batch;
3492 
3493 #else
3494 	/* The deferral and batching of frees should be suppressed under NOMMU
3495 	 * conditions.
3496 	 *
3497 	 * The problem is that NOMMU needs to be able to allocate large chunks
3498 	 * of contiguous memory as there's no hardware page translation to
3499 	 * assemble apparent contiguous memory from discontiguous pages.
3500 	 *
3501 	 * Queueing large contiguous runs of pages for batching, however,
3502 	 * causes the pages to actually be freed in smaller chunks.  As there
3503 	 * can be a significant delay between the individual batches being
3504 	 * recycled, this leads to the once large chunks of space being
3505 	 * fragmented and becoming unavailable for high-order allocations.
3506 	 */
3507 	return 0;
3508 #endif
3509 }
3510 
setup_pageset(struct per_cpu_pageset * p,unsigned long batch)3511 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
3512 {
3513 	struct per_cpu_pages *pcp;
3514 	int migratetype;
3515 
3516 	memset(p, 0, sizeof(*p));
3517 
3518 	pcp = &p->pcp;
3519 	pcp->count = 0;
3520 	pcp->high = 6 * batch;
3521 	pcp->batch = max(1UL, 1 * batch);
3522 	for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
3523 		INIT_LIST_HEAD(&pcp->lists[migratetype]);
3524 }
3525 
3526 /*
3527  * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
3528  * to the value high for the pageset p.
3529  */
3530 
setup_pagelist_highmark(struct per_cpu_pageset * p,unsigned long high)3531 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
3532 				unsigned long high)
3533 {
3534 	struct per_cpu_pages *pcp;
3535 
3536 	pcp = &p->pcp;
3537 	pcp->high = high;
3538 	pcp->batch = max(1UL, high/4);
3539 	if ((high/4) > (PAGE_SHIFT * 8))
3540 		pcp->batch = PAGE_SHIFT * 8;
3541 }
3542 
setup_zone_pageset(struct zone * zone)3543 static __meminit void setup_zone_pageset(struct zone *zone)
3544 {
3545 	int cpu;
3546 
3547 	zone->pageset = alloc_percpu(struct per_cpu_pageset);
3548 
3549 	for_each_possible_cpu(cpu) {
3550 		struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
3551 
3552 		setup_pageset(pcp, zone_batchsize(zone));
3553 
3554 		if (percpu_pagelist_fraction)
3555 			setup_pagelist_highmark(pcp,
3556 				(zone->present_pages /
3557 					percpu_pagelist_fraction));
3558 	}
3559 }
3560 
3561 /*
3562  * Allocate per cpu pagesets and initialize them.
3563  * Before this call only boot pagesets were available.
3564  */
setup_per_cpu_pageset(void)3565 void __init setup_per_cpu_pageset(void)
3566 {
3567 	struct zone *zone;
3568 
3569 	for_each_populated_zone(zone)
3570 		setup_zone_pageset(zone);
3571 }
3572 
3573 static noinline __init_refok
zone_wait_table_init(struct zone * zone,unsigned long zone_size_pages)3574 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
3575 {
3576 	int i;
3577 	struct pglist_data *pgdat = zone->zone_pgdat;
3578 	size_t alloc_size;
3579 
3580 	/*
3581 	 * The per-page waitqueue mechanism uses hashed waitqueues
3582 	 * per zone.
3583 	 */
3584 	zone->wait_table_hash_nr_entries =
3585 		 wait_table_hash_nr_entries(zone_size_pages);
3586 	zone->wait_table_bits =
3587 		wait_table_bits(zone->wait_table_hash_nr_entries);
3588 	alloc_size = zone->wait_table_hash_nr_entries
3589 					* sizeof(wait_queue_head_t);
3590 
3591 	if (!slab_is_available()) {
3592 		zone->wait_table = (wait_queue_head_t *)
3593 			alloc_bootmem_node_nopanic(pgdat, alloc_size);
3594 	} else {
3595 		/*
3596 		 * This case means that a zone whose size was 0 gets new memory
3597 		 * via memory hot-add.
3598 		 * But it may be the case that a new node was hot-added.  In
3599 		 * this case vmalloc() will not be able to use this new node's
3600 		 * memory - this wait_table must be initialized to use this new
3601 		 * node itself as well.
3602 		 * To use this new node's memory, further consideration will be
3603 		 * necessary.
3604 		 */
3605 		zone->wait_table = vmalloc(alloc_size);
3606 	}
3607 	if (!zone->wait_table)
3608 		return -ENOMEM;
3609 
3610 	for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
3611 		init_waitqueue_head(zone->wait_table + i);
3612 
3613 	return 0;
3614 }
3615 
__zone_pcp_update(void * data)3616 static int __zone_pcp_update(void *data)
3617 {
3618 	struct zone *zone = data;
3619 	int cpu;
3620 	unsigned long batch = zone_batchsize(zone), flags;
3621 
3622 	for_each_possible_cpu(cpu) {
3623 		struct per_cpu_pageset *pset;
3624 		struct per_cpu_pages *pcp;
3625 
3626 		pset = per_cpu_ptr(zone->pageset, cpu);
3627 		pcp = &pset->pcp;
3628 
3629 		local_irq_save(flags);
3630 		free_pcppages_bulk(zone, pcp->count, pcp);
3631 		setup_pageset(pset, batch);
3632 		local_irq_restore(flags);
3633 	}
3634 	return 0;
3635 }
3636 
zone_pcp_update(struct zone * zone)3637 void zone_pcp_update(struct zone *zone)
3638 {
3639 	stop_machine(__zone_pcp_update, zone, NULL);
3640 }
3641 
zone_pcp_init(struct zone * zone)3642 static __meminit void zone_pcp_init(struct zone *zone)
3643 {
3644 	/*
3645 	 * per cpu subsystem is not up at this point. The following code
3646 	 * relies on the ability of the linker to provide the
3647 	 * offset of a (static) per cpu variable into the per cpu area.
3648 	 */
3649 	zone->pageset = &boot_pageset;
3650 
3651 	if (zone->present_pages)
3652 		printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
3653 			zone->name, zone->present_pages,
3654 					 zone_batchsize(zone));
3655 }
3656 
init_currently_empty_zone(struct zone * zone,unsigned long zone_start_pfn,unsigned long size,enum memmap_context context)3657 __meminit int init_currently_empty_zone(struct zone *zone,
3658 					unsigned long zone_start_pfn,
3659 					unsigned long size,
3660 					enum memmap_context context)
3661 {
3662 	struct pglist_data *pgdat = zone->zone_pgdat;
3663 	int ret;
3664 	ret = zone_wait_table_init(zone, size);
3665 	if (ret)
3666 		return ret;
3667 	pgdat->nr_zones = zone_idx(zone) + 1;
3668 
3669 	zone->zone_start_pfn = zone_start_pfn;
3670 
3671 	mminit_dprintk(MMINIT_TRACE, "memmap_init",
3672 			"Initialising map node %d zone %lu pfns %lu -> %lu\n",
3673 			pgdat->node_id,
3674 			(unsigned long)zone_idx(zone),
3675 			zone_start_pfn, (zone_start_pfn + size));
3676 
3677 	zone_init_free_lists(zone);
3678 
3679 	return 0;
3680 }
3681 
3682 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
3683 /*
3684  * Basic iterator support. Return the first range of PFNs for a node
3685  * Note: nid == MAX_NUMNODES returns first region regardless of node
3686  */
first_active_region_index_in_nid(int nid)3687 static int __meminit first_active_region_index_in_nid(int nid)
3688 {
3689 	int i;
3690 
3691 	for (i = 0; i < nr_nodemap_entries; i++)
3692 		if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
3693 			return i;
3694 
3695 	return -1;
3696 }
3697 
3698 /*
3699  * Basic iterator support. Return the next active range of PFNs for a node
3700  * Note: nid == MAX_NUMNODES returns next region regardless of node
3701  */
next_active_region_index_in_nid(int index,int nid)3702 static int __meminit next_active_region_index_in_nid(int index, int nid)
3703 {
3704 	for (index = index + 1; index < nr_nodemap_entries; index++)
3705 		if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
3706 			return index;
3707 
3708 	return -1;
3709 }
3710 
3711 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
3712 /*
3713  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
3714  * Architectures may implement their own version but if add_active_range()
3715  * was used and there are no special requirements, this is a convenient
3716  * alternative
3717  */
__early_pfn_to_nid(unsigned long pfn)3718 int __meminit __early_pfn_to_nid(unsigned long pfn)
3719 {
3720 	int i;
3721 
3722 	for (i = 0; i < nr_nodemap_entries; i++) {
3723 		unsigned long start_pfn = early_node_map[i].start_pfn;
3724 		unsigned long end_pfn = early_node_map[i].end_pfn;
3725 
3726 		if (start_pfn <= pfn && pfn < end_pfn)
3727 			return early_node_map[i].nid;
3728 	}
3729 	/* This is a memory hole */
3730 	return -1;
3731 }
3732 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
3733 
early_pfn_to_nid(unsigned long pfn)3734 int __meminit early_pfn_to_nid(unsigned long pfn)
3735 {
3736 	int nid;
3737 
3738 	nid = __early_pfn_to_nid(pfn);
3739 	if (nid >= 0)
3740 		return nid;
3741 	/* just returns 0 */
3742 	return 0;
3743 }
3744 
3745 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
early_pfn_in_nid(unsigned long pfn,int node)3746 bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
3747 {
3748 	int nid;
3749 
3750 	nid = __early_pfn_to_nid(pfn);
3751 	if (nid >= 0 && nid != node)
3752 		return false;
3753 	return true;
3754 }
3755 #endif
3756 
3757 /* Basic iterator support to walk early_node_map[] */
3758 #define for_each_active_range_index_in_nid(i, nid) \
3759 	for (i = first_active_region_index_in_nid(nid); i != -1; \
3760 				i = next_active_region_index_in_nid(i, nid))
3761 
3762 /**
3763  * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
3764  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
3765  * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
3766  *
3767  * If an architecture guarantees that all ranges registered with
3768  * add_active_ranges() contain no holes and may be freed, this
3769  * this function may be used instead of calling free_bootmem() manually.
3770  */
free_bootmem_with_active_regions(int nid,unsigned long max_low_pfn)3771 void __init free_bootmem_with_active_regions(int nid,
3772 						unsigned long max_low_pfn)
3773 {
3774 	int i;
3775 
3776 	for_each_active_range_index_in_nid(i, nid) {
3777 		unsigned long size_pages = 0;
3778 		unsigned long end_pfn = early_node_map[i].end_pfn;
3779 
3780 		if (early_node_map[i].start_pfn >= max_low_pfn)
3781 			continue;
3782 
3783 		if (end_pfn > max_low_pfn)
3784 			end_pfn = max_low_pfn;
3785 
3786 		size_pages = end_pfn - early_node_map[i].start_pfn;
3787 		free_bootmem_node(NODE_DATA(early_node_map[i].nid),
3788 				PFN_PHYS(early_node_map[i].start_pfn),
3789 				size_pages << PAGE_SHIFT);
3790 	}
3791 }
3792 
3793 #ifdef CONFIG_HAVE_MEMBLOCK
3794 /*
3795  * Basic iterator support. Return the last range of PFNs for a node
3796  * Note: nid == MAX_NUMNODES returns last region regardless of node
3797  */
last_active_region_index_in_nid(int nid)3798 static int __meminit last_active_region_index_in_nid(int nid)
3799 {
3800 	int i;
3801 
3802 	for (i = nr_nodemap_entries - 1; i >= 0; i--)
3803 		if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
3804 			return i;
3805 
3806 	return -1;
3807 }
3808 
3809 /*
3810  * Basic iterator support. Return the previous active range of PFNs for a node
3811  * Note: nid == MAX_NUMNODES returns next region regardless of node
3812  */
previous_active_region_index_in_nid(int index,int nid)3813 static int __meminit previous_active_region_index_in_nid(int index, int nid)
3814 {
3815 	for (index = index - 1; index >= 0; index--)
3816 		if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
3817 			return index;
3818 
3819 	return -1;
3820 }
3821 
3822 #define for_each_active_range_index_in_nid_reverse(i, nid) \
3823 	for (i = last_active_region_index_in_nid(nid); i != -1; \
3824 				i = previous_active_region_index_in_nid(i, nid))
3825 
find_memory_core_early(int nid,u64 size,u64 align,u64 goal,u64 limit)3826 u64 __init find_memory_core_early(int nid, u64 size, u64 align,
3827 					u64 goal, u64 limit)
3828 {
3829 	int i;
3830 
3831 	/* Need to go over early_node_map to find out good range for node */
3832 	for_each_active_range_index_in_nid_reverse(i, nid) {
3833 		u64 addr;
3834 		u64 ei_start, ei_last;
3835 		u64 final_start, final_end;
3836 
3837 		ei_last = early_node_map[i].end_pfn;
3838 		ei_last <<= PAGE_SHIFT;
3839 		ei_start = early_node_map[i].start_pfn;
3840 		ei_start <<= PAGE_SHIFT;
3841 
3842 		final_start = max(ei_start, goal);
3843 		final_end = min(ei_last, limit);
3844 
3845 		if (final_start >= final_end)
3846 			continue;
3847 
3848 		addr = memblock_find_in_range(final_start, final_end, size, align);
3849 
3850 		if (addr == MEMBLOCK_ERROR)
3851 			continue;
3852 
3853 		return addr;
3854 	}
3855 
3856 	return MEMBLOCK_ERROR;
3857 }
3858 #endif
3859 
add_from_early_node_map(struct range * range,int az,int nr_range,int nid)3860 int __init add_from_early_node_map(struct range *range, int az,
3861 				   int nr_range, int nid)
3862 {
3863 	int i;
3864 	u64 start, end;
3865 
3866 	/* need to go over early_node_map to find out good range for node */
3867 	for_each_active_range_index_in_nid(i, nid) {
3868 		start = early_node_map[i].start_pfn;
3869 		end = early_node_map[i].end_pfn;
3870 		nr_range = add_range(range, az, nr_range, start, end);
3871 	}
3872 	return nr_range;
3873 }
3874 
work_with_active_regions(int nid,work_fn_t work_fn,void * data)3875 void __init work_with_active_regions(int nid, work_fn_t work_fn, void *data)
3876 {
3877 	int i;
3878 	int ret;
3879 
3880 	for_each_active_range_index_in_nid(i, nid) {
3881 		ret = work_fn(early_node_map[i].start_pfn,
3882 			      early_node_map[i].end_pfn, data);
3883 		if (ret)
3884 			break;
3885 	}
3886 }
3887 /**
3888  * sparse_memory_present_with_active_regions - Call memory_present for each active range
3889  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
3890  *
3891  * If an architecture guarantees that all ranges registered with
3892  * add_active_ranges() contain no holes and may be freed, this
3893  * function may be used instead of calling memory_present() manually.
3894  */
sparse_memory_present_with_active_regions(int nid)3895 void __init sparse_memory_present_with_active_regions(int nid)
3896 {
3897 	int i;
3898 
3899 	for_each_active_range_index_in_nid(i, nid)
3900 		memory_present(early_node_map[i].nid,
3901 				early_node_map[i].start_pfn,
3902 				early_node_map[i].end_pfn);
3903 }
3904 
3905 /**
3906  * get_pfn_range_for_nid - Return the start and end page frames for a node
3907  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
3908  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
3909  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
3910  *
3911  * It returns the start and end page frame of a node based on information
3912  * provided by an arch calling add_active_range(). If called for a node
3913  * with no available memory, a warning is printed and the start and end
3914  * PFNs will be 0.
3915  */
get_pfn_range_for_nid(unsigned int nid,unsigned long * start_pfn,unsigned long * end_pfn)3916 void __meminit get_pfn_range_for_nid(unsigned int nid,
3917 			unsigned long *start_pfn, unsigned long *end_pfn)
3918 {
3919 	int i;
3920 	*start_pfn = -1UL;
3921 	*end_pfn = 0;
3922 
3923 	for_each_active_range_index_in_nid(i, nid) {
3924 		*start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
3925 		*end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
3926 	}
3927 
3928 	if (*start_pfn == -1UL)
3929 		*start_pfn = 0;
3930 }
3931 
3932 /*
3933  * This finds a zone that can be used for ZONE_MOVABLE pages. The
3934  * assumption is made that zones within a node are ordered in monotonic
3935  * increasing memory addresses so that the "highest" populated zone is used
3936  */
find_usable_zone_for_movable(void)3937 static void __init find_usable_zone_for_movable(void)
3938 {
3939 	int zone_index;
3940 	for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
3941 		if (zone_index == ZONE_MOVABLE)
3942 			continue;
3943 
3944 		if (arch_zone_highest_possible_pfn[zone_index] >
3945 				arch_zone_lowest_possible_pfn[zone_index])
3946 			break;
3947 	}
3948 
3949 	VM_BUG_ON(zone_index == -1);
3950 	movable_zone = zone_index;
3951 }
3952 
3953 /*
3954  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
3955  * because it is sized independent of architecture. Unlike the other zones,
3956  * the starting point for ZONE_MOVABLE is not fixed. It may be different
3957  * in each node depending on the size of each node and how evenly kernelcore
3958  * is distributed. This helper function adjusts the zone ranges
3959  * provided by the architecture for a given node by using the end of the
3960  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
3961  * zones within a node are in order of monotonic increases memory addresses
3962  */
adjust_zone_range_for_zone_movable(int nid,unsigned long zone_type,unsigned long node_start_pfn,unsigned long node_end_pfn,unsigned long * zone_start_pfn,unsigned long * zone_end_pfn)3963 static void __meminit adjust_zone_range_for_zone_movable(int nid,
3964 					unsigned long zone_type,
3965 					unsigned long node_start_pfn,
3966 					unsigned long node_end_pfn,
3967 					unsigned long *zone_start_pfn,
3968 					unsigned long *zone_end_pfn)
3969 {
3970 	/* Only adjust if ZONE_MOVABLE is on this node */
3971 	if (zone_movable_pfn[nid]) {
3972 		/* Size ZONE_MOVABLE */
3973 		if (zone_type == ZONE_MOVABLE) {
3974 			*zone_start_pfn = zone_movable_pfn[nid];
3975 			*zone_end_pfn = min(node_end_pfn,
3976 				arch_zone_highest_possible_pfn[movable_zone]);
3977 
3978 		/* Adjust for ZONE_MOVABLE starting within this range */
3979 		} else if (*zone_start_pfn < zone_movable_pfn[nid] &&
3980 				*zone_end_pfn > zone_movable_pfn[nid]) {
3981 			*zone_end_pfn = zone_movable_pfn[nid];
3982 
3983 		/* Check if this whole range is within ZONE_MOVABLE */
3984 		} else if (*zone_start_pfn >= zone_movable_pfn[nid])
3985 			*zone_start_pfn = *zone_end_pfn;
3986 	}
3987 }
3988 
3989 /*
3990  * Return the number of pages a zone spans in a node, including holes
3991  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
3992  */
zone_spanned_pages_in_node(int nid,unsigned long zone_type,unsigned long * ignored)3993 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
3994 					unsigned long zone_type,
3995 					unsigned long *ignored)
3996 {
3997 	unsigned long node_start_pfn, node_end_pfn;
3998 	unsigned long zone_start_pfn, zone_end_pfn;
3999 
4000 	/* Get the start and end of the node and zone */
4001 	get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4002 	zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4003 	zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4004 	adjust_zone_range_for_zone_movable(nid, zone_type,
4005 				node_start_pfn, node_end_pfn,
4006 				&zone_start_pfn, &zone_end_pfn);
4007 
4008 	/* Check that this node has pages within the zone's required range */
4009 	if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4010 		return 0;
4011 
4012 	/* Move the zone boundaries inside the node if necessary */
4013 	zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4014 	zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4015 
4016 	/* Return the spanned pages */
4017 	return zone_end_pfn - zone_start_pfn;
4018 }
4019 
4020 /*
4021  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4022  * then all holes in the requested range will be accounted for.
4023  */
__absent_pages_in_range(int nid,unsigned long range_start_pfn,unsigned long range_end_pfn)4024 unsigned long __meminit __absent_pages_in_range(int nid,
4025 				unsigned long range_start_pfn,
4026 				unsigned long range_end_pfn)
4027 {
4028 	int i = 0;
4029 	unsigned long prev_end_pfn = 0, hole_pages = 0;
4030 	unsigned long start_pfn;
4031 
4032 	/* Find the end_pfn of the first active range of pfns in the node */
4033 	i = first_active_region_index_in_nid(nid);
4034 	if (i == -1)
4035 		return 0;
4036 
4037 	prev_end_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
4038 
4039 	/* Account for ranges before physical memory on this node */
4040 	if (early_node_map[i].start_pfn > range_start_pfn)
4041 		hole_pages = prev_end_pfn - range_start_pfn;
4042 
4043 	/* Find all holes for the zone within the node */
4044 	for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
4045 
4046 		/* No need to continue if prev_end_pfn is outside the zone */
4047 		if (prev_end_pfn >= range_end_pfn)
4048 			break;
4049 
4050 		/* Make sure the end of the zone is not within the hole */
4051 		start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
4052 		prev_end_pfn = max(prev_end_pfn, range_start_pfn);
4053 
4054 		/* Update the hole size cound and move on */
4055 		if (start_pfn > range_start_pfn) {
4056 			BUG_ON(prev_end_pfn > start_pfn);
4057 			hole_pages += start_pfn - prev_end_pfn;
4058 		}
4059 		prev_end_pfn = early_node_map[i].end_pfn;
4060 	}
4061 
4062 	/* Account for ranges past physical memory on this node */
4063 	if (range_end_pfn > prev_end_pfn)
4064 		hole_pages += range_end_pfn -
4065 				max(range_start_pfn, prev_end_pfn);
4066 
4067 	return hole_pages;
4068 }
4069 
4070 /**
4071  * absent_pages_in_range - Return number of page frames in holes within a range
4072  * @start_pfn: The start PFN to start searching for holes
4073  * @end_pfn: The end PFN to stop searching for holes
4074  *
4075  * It returns the number of pages frames in memory holes within a range.
4076  */
absent_pages_in_range(unsigned long start_pfn,unsigned long end_pfn)4077 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4078 							unsigned long end_pfn)
4079 {
4080 	return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4081 }
4082 
4083 /* Return the number of page frames in holes in a zone on a node */
zone_absent_pages_in_node(int nid,unsigned long zone_type,unsigned long * ignored)4084 static unsigned long __meminit zone_absent_pages_in_node(int nid,
4085 					unsigned long zone_type,
4086 					unsigned long *ignored)
4087 {
4088 	unsigned long node_start_pfn, node_end_pfn;
4089 	unsigned long zone_start_pfn, zone_end_pfn;
4090 
4091 	get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4092 	zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
4093 							node_start_pfn);
4094 	zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
4095 							node_end_pfn);
4096 
4097 	adjust_zone_range_for_zone_movable(nid, zone_type,
4098 			node_start_pfn, node_end_pfn,
4099 			&zone_start_pfn, &zone_end_pfn);
4100 	return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4101 }
4102 
4103 #else
zone_spanned_pages_in_node(int nid,unsigned long zone_type,unsigned long * zones_size)4104 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4105 					unsigned long zone_type,
4106 					unsigned long *zones_size)
4107 {
4108 	return zones_size[zone_type];
4109 }
4110 
zone_absent_pages_in_node(int nid,unsigned long zone_type,unsigned long * zholes_size)4111 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4112 						unsigned long zone_type,
4113 						unsigned long *zholes_size)
4114 {
4115 	if (!zholes_size)
4116 		return 0;
4117 
4118 	return zholes_size[zone_type];
4119 }
4120 
4121 #endif
4122 
calculate_node_totalpages(struct pglist_data * pgdat,unsigned long * zones_size,unsigned long * zholes_size)4123 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4124 		unsigned long *zones_size, unsigned long *zholes_size)
4125 {
4126 	unsigned long realtotalpages, totalpages = 0;
4127 	enum zone_type i;
4128 
4129 	for (i = 0; i < MAX_NR_ZONES; i++)
4130 		totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4131 								zones_size);
4132 	pgdat->node_spanned_pages = totalpages;
4133 
4134 	realtotalpages = totalpages;
4135 	for (i = 0; i < MAX_NR_ZONES; i++)
4136 		realtotalpages -=
4137 			zone_absent_pages_in_node(pgdat->node_id, i,
4138 								zholes_size);
4139 	pgdat->node_present_pages = realtotalpages;
4140 	printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4141 							realtotalpages);
4142 }
4143 
4144 #ifndef CONFIG_SPARSEMEM
4145 /*
4146  * Calculate the size of the zone->blockflags rounded to an unsigned long
4147  * Start by making sure zonesize is a multiple of pageblock_order by rounding
4148  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4149  * round what is now in bits to nearest long in bits, then return it in
4150  * bytes.
4151  */
usemap_size(unsigned long zonesize)4152 static unsigned long __init usemap_size(unsigned long zonesize)
4153 {
4154 	unsigned long usemapsize;
4155 
4156 	usemapsize = roundup(zonesize, pageblock_nr_pages);
4157 	usemapsize = usemapsize >> pageblock_order;
4158 	usemapsize *= NR_PAGEBLOCK_BITS;
4159 	usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4160 
4161 	return usemapsize / 8;
4162 }
4163 
setup_usemap(struct pglist_data * pgdat,struct zone * zone,unsigned long zonesize)4164 static void __init setup_usemap(struct pglist_data *pgdat,
4165 				struct zone *zone, unsigned long zonesize)
4166 {
4167 	unsigned long usemapsize = usemap_size(zonesize);
4168 	zone->pageblock_flags = NULL;
4169 	if (usemapsize)
4170 		zone->pageblock_flags = alloc_bootmem_node_nopanic(pgdat,
4171 								   usemapsize);
4172 }
4173 #else
setup_usemap(struct pglist_data * pgdat,struct zone * zone,unsigned long zonesize)4174 static inline void setup_usemap(struct pglist_data *pgdat,
4175 				struct zone *zone, unsigned long zonesize) {}
4176 #endif /* CONFIG_SPARSEMEM */
4177 
4178 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4179 
4180 /* Return a sensible default order for the pageblock size. */
pageblock_default_order(void)4181 static inline int pageblock_default_order(void)
4182 {
4183 	if (HPAGE_SHIFT > PAGE_SHIFT)
4184 		return HUGETLB_PAGE_ORDER;
4185 
4186 	return MAX_ORDER-1;
4187 }
4188 
4189 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
set_pageblock_order(unsigned int order)4190 static inline void __init set_pageblock_order(unsigned int order)
4191 {
4192 	/* Check that pageblock_nr_pages has not already been setup */
4193 	if (pageblock_order)
4194 		return;
4195 
4196 	/*
4197 	 * Assume the largest contiguous order of interest is a huge page.
4198 	 * This value may be variable depending on boot parameters on IA64
4199 	 */
4200 	pageblock_order = order;
4201 }
4202 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4203 
4204 /*
4205  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4206  * and pageblock_default_order() are unused as pageblock_order is set
4207  * at compile-time. See include/linux/pageblock-flags.h for the values of
4208  * pageblock_order based on the kernel config
4209  */
pageblock_default_order(unsigned int order)4210 static inline int pageblock_default_order(unsigned int order)
4211 {
4212 	return MAX_ORDER-1;
4213 }
4214 #define set_pageblock_order(x)	do {} while (0)
4215 
4216 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4217 
4218 /*
4219  * Set up the zone data structures:
4220  *   - mark all pages reserved
4221  *   - mark all memory queues empty
4222  *   - clear the memory bitmaps
4223  */
free_area_init_core(struct pglist_data * pgdat,unsigned long * zones_size,unsigned long * zholes_size)4224 static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4225 		unsigned long *zones_size, unsigned long *zholes_size)
4226 {
4227 	enum zone_type j;
4228 	int nid = pgdat->node_id;
4229 	unsigned long zone_start_pfn = pgdat->node_start_pfn;
4230 	int ret;
4231 
4232 	pgdat_resize_init(pgdat);
4233 	pgdat->nr_zones = 0;
4234 	init_waitqueue_head(&pgdat->kswapd_wait);
4235 	pgdat->kswapd_max_order = 0;
4236 	pgdat_page_cgroup_init(pgdat);
4237 
4238 	for (j = 0; j < MAX_NR_ZONES; j++) {
4239 		struct zone *zone = pgdat->node_zones + j;
4240 		unsigned long size, realsize, memmap_pages;
4241 		enum lru_list l;
4242 
4243 		size = zone_spanned_pages_in_node(nid, j, zones_size);
4244 		realsize = size - zone_absent_pages_in_node(nid, j,
4245 								zholes_size);
4246 
4247 		/*
4248 		 * Adjust realsize so that it accounts for how much memory
4249 		 * is used by this zone for memmap. This affects the watermark
4250 		 * and per-cpu initialisations
4251 		 */
4252 		memmap_pages =
4253 			PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
4254 		if (realsize >= memmap_pages) {
4255 			realsize -= memmap_pages;
4256 			if (memmap_pages)
4257 				printk(KERN_DEBUG
4258 				       "  %s zone: %lu pages used for memmap\n",
4259 				       zone_names[j], memmap_pages);
4260 		} else
4261 			printk(KERN_WARNING
4262 				"  %s zone: %lu pages exceeds realsize %lu\n",
4263 				zone_names[j], memmap_pages, realsize);
4264 
4265 		/* Account for reserved pages */
4266 		if (j == 0 && realsize > dma_reserve) {
4267 			realsize -= dma_reserve;
4268 			printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
4269 					zone_names[0], dma_reserve);
4270 		}
4271 
4272 		if (!is_highmem_idx(j))
4273 			nr_kernel_pages += realsize;
4274 		nr_all_pages += realsize;
4275 
4276 		zone->spanned_pages = size;
4277 		zone->present_pages = realsize;
4278 #ifdef CONFIG_NUMA
4279 		zone->node = nid;
4280 		zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
4281 						/ 100;
4282 		zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
4283 #endif
4284 		zone->name = zone_names[j];
4285 		spin_lock_init(&zone->lock);
4286 		spin_lock_init(&zone->lru_lock);
4287 		zone_seqlock_init(zone);
4288 		zone->zone_pgdat = pgdat;
4289 
4290 		zone_pcp_init(zone);
4291 		for_each_lru(l) {
4292 			INIT_LIST_HEAD(&zone->lru[l].list);
4293 			zone->reclaim_stat.nr_saved_scan[l] = 0;
4294 		}
4295 		zone->reclaim_stat.recent_rotated[0] = 0;
4296 		zone->reclaim_stat.recent_rotated[1] = 0;
4297 		zone->reclaim_stat.recent_scanned[0] = 0;
4298 		zone->reclaim_stat.recent_scanned[1] = 0;
4299 		zap_zone_vm_stats(zone);
4300 		zone->flags = 0;
4301 		if (!size)
4302 			continue;
4303 
4304 		set_pageblock_order(pageblock_default_order());
4305 		setup_usemap(pgdat, zone, size);
4306 		ret = init_currently_empty_zone(zone, zone_start_pfn,
4307 						size, MEMMAP_EARLY);
4308 		BUG_ON(ret);
4309 		memmap_init(size, nid, j, zone_start_pfn);
4310 		zone_start_pfn += size;
4311 	}
4312 }
4313 
alloc_node_mem_map(struct pglist_data * pgdat)4314 static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4315 {
4316 	/* Skip empty nodes */
4317 	if (!pgdat->node_spanned_pages)
4318 		return;
4319 
4320 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4321 	/* ia64 gets its own node_mem_map, before this, without bootmem */
4322 	if (!pgdat->node_mem_map) {
4323 		unsigned long size, start, end;
4324 		struct page *map;
4325 
4326 		/*
4327 		 * The zone's endpoints aren't required to be MAX_ORDER
4328 		 * aligned but the node_mem_map endpoints must be in order
4329 		 * for the buddy allocator to function correctly.
4330 		 */
4331 		start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4332 		end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
4333 		end = ALIGN(end, MAX_ORDER_NR_PAGES);
4334 		size =  (end - start) * sizeof(struct page);
4335 		map = alloc_remap(pgdat->node_id, size);
4336 		if (!map)
4337 			map = alloc_bootmem_node_nopanic(pgdat, size);
4338 		pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4339 	}
4340 #ifndef CONFIG_NEED_MULTIPLE_NODES
4341 	/*
4342 	 * With no DISCONTIG, the global mem_map is just set as node 0's
4343 	 */
4344 	if (pgdat == NODE_DATA(0)) {
4345 		mem_map = NODE_DATA(0)->node_mem_map;
4346 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4347 		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4348 			mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4349 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4350 	}
4351 #endif
4352 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
4353 }
4354 
free_area_init_node(int nid,unsigned long * zones_size,unsigned long node_start_pfn,unsigned long * zholes_size)4355 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4356 		unsigned long node_start_pfn, unsigned long *zholes_size)
4357 {
4358 	pg_data_t *pgdat = NODE_DATA(nid);
4359 
4360 	pgdat->node_id = nid;
4361 	pgdat->node_start_pfn = node_start_pfn;
4362 	calculate_node_totalpages(pgdat, zones_size, zholes_size);
4363 
4364 	alloc_node_mem_map(pgdat);
4365 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4366 	printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4367 		nid, (unsigned long)pgdat,
4368 		(unsigned long)pgdat->node_mem_map);
4369 #endif
4370 
4371 	free_area_init_core(pgdat, zones_size, zholes_size);
4372 }
4373 
4374 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4375 
4376 #if MAX_NUMNODES > 1
4377 /*
4378  * Figure out the number of possible node ids.
4379  */
setup_nr_node_ids(void)4380 static void __init setup_nr_node_ids(void)
4381 {
4382 	unsigned int node;
4383 	unsigned int highest = 0;
4384 
4385 	for_each_node_mask(node, node_possible_map)
4386 		highest = node;
4387 	nr_node_ids = highest + 1;
4388 }
4389 #else
setup_nr_node_ids(void)4390 static inline void setup_nr_node_ids(void)
4391 {
4392 }
4393 #endif
4394 
4395 /**
4396  * add_active_range - Register a range of PFNs backed by physical memory
4397  * @nid: The node ID the range resides on
4398  * @start_pfn: The start PFN of the available physical memory
4399  * @end_pfn: The end PFN of the available physical memory
4400  *
4401  * These ranges are stored in an early_node_map[] and later used by
4402  * free_area_init_nodes() to calculate zone sizes and holes. If the
4403  * range spans a memory hole, it is up to the architecture to ensure
4404  * the memory is not freed by the bootmem allocator. If possible
4405  * the range being registered will be merged with existing ranges.
4406  */
add_active_range(unsigned int nid,unsigned long start_pfn,unsigned long end_pfn)4407 void __init add_active_range(unsigned int nid, unsigned long start_pfn,
4408 						unsigned long end_pfn)
4409 {
4410 	int i;
4411 
4412 	mminit_dprintk(MMINIT_TRACE, "memory_register",
4413 			"Entering add_active_range(%d, %#lx, %#lx) "
4414 			"%d entries of %d used\n",
4415 			nid, start_pfn, end_pfn,
4416 			nr_nodemap_entries, MAX_ACTIVE_REGIONS);
4417 
4418 	mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
4419 
4420 	/* Merge with existing active regions if possible */
4421 	for (i = 0; i < nr_nodemap_entries; i++) {
4422 		if (early_node_map[i].nid != nid)
4423 			continue;
4424 
4425 		/* Skip if an existing region covers this new one */
4426 		if (start_pfn >= early_node_map[i].start_pfn &&
4427 				end_pfn <= early_node_map[i].end_pfn)
4428 			return;
4429 
4430 		/* Merge forward if suitable */
4431 		if (start_pfn <= early_node_map[i].end_pfn &&
4432 				end_pfn > early_node_map[i].end_pfn) {
4433 			early_node_map[i].end_pfn = end_pfn;
4434 			return;
4435 		}
4436 
4437 		/* Merge backward if suitable */
4438 		if (start_pfn < early_node_map[i].start_pfn &&
4439 				end_pfn >= early_node_map[i].start_pfn) {
4440 			early_node_map[i].start_pfn = start_pfn;
4441 			return;
4442 		}
4443 	}
4444 
4445 	/* Check that early_node_map is large enough */
4446 	if (i >= MAX_ACTIVE_REGIONS) {
4447 		printk(KERN_CRIT "More than %d memory regions, truncating\n",
4448 							MAX_ACTIVE_REGIONS);
4449 		return;
4450 	}
4451 
4452 	early_node_map[i].nid = nid;
4453 	early_node_map[i].start_pfn = start_pfn;
4454 	early_node_map[i].end_pfn = end_pfn;
4455 	nr_nodemap_entries = i + 1;
4456 }
4457 
4458 /**
4459  * remove_active_range - Shrink an existing registered range of PFNs
4460  * @nid: The node id the range is on that should be shrunk
4461  * @start_pfn: The new PFN of the range
4462  * @end_pfn: The new PFN of the range
4463  *
4464  * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
4465  * The map is kept near the end physical page range that has already been
4466  * registered. This function allows an arch to shrink an existing registered
4467  * range.
4468  */
remove_active_range(unsigned int nid,unsigned long start_pfn,unsigned long end_pfn)4469 void __init remove_active_range(unsigned int nid, unsigned long start_pfn,
4470 				unsigned long end_pfn)
4471 {
4472 	int i, j;
4473 	int removed = 0;
4474 
4475 	printk(KERN_DEBUG "remove_active_range (%d, %lu, %lu)\n",
4476 			  nid, start_pfn, end_pfn);
4477 
4478 	/* Find the old active region end and shrink */
4479 	for_each_active_range_index_in_nid(i, nid) {
4480 		if (early_node_map[i].start_pfn >= start_pfn &&
4481 		    early_node_map[i].end_pfn <= end_pfn) {
4482 			/* clear it */
4483 			early_node_map[i].start_pfn = 0;
4484 			early_node_map[i].end_pfn = 0;
4485 			removed = 1;
4486 			continue;
4487 		}
4488 		if (early_node_map[i].start_pfn < start_pfn &&
4489 		    early_node_map[i].end_pfn > start_pfn) {
4490 			unsigned long temp_end_pfn = early_node_map[i].end_pfn;
4491 			early_node_map[i].end_pfn = start_pfn;
4492 			if (temp_end_pfn > end_pfn)
4493 				add_active_range(nid, end_pfn, temp_end_pfn);
4494 			continue;
4495 		}
4496 		if (early_node_map[i].start_pfn >= start_pfn &&
4497 		    early_node_map[i].end_pfn > end_pfn &&
4498 		    early_node_map[i].start_pfn < end_pfn) {
4499 			early_node_map[i].start_pfn = end_pfn;
4500 			continue;
4501 		}
4502 	}
4503 
4504 	if (!removed)
4505 		return;
4506 
4507 	/* remove the blank ones */
4508 	for (i = nr_nodemap_entries - 1; i > 0; i--) {
4509 		if (early_node_map[i].nid != nid)
4510 			continue;
4511 		if (early_node_map[i].end_pfn)
4512 			continue;
4513 		/* we found it, get rid of it */
4514 		for (j = i; j < nr_nodemap_entries - 1; j++)
4515 			memcpy(&early_node_map[j], &early_node_map[j+1],
4516 				sizeof(early_node_map[j]));
4517 		j = nr_nodemap_entries - 1;
4518 		memset(&early_node_map[j], 0, sizeof(early_node_map[j]));
4519 		nr_nodemap_entries--;
4520 	}
4521 }
4522 
4523 /**
4524  * remove_all_active_ranges - Remove all currently registered regions
4525  *
4526  * During discovery, it may be found that a table like SRAT is invalid
4527  * and an alternative discovery method must be used. This function removes
4528  * all currently registered regions.
4529  */
remove_all_active_ranges(void)4530 void __init remove_all_active_ranges(void)
4531 {
4532 	memset(early_node_map, 0, sizeof(early_node_map));
4533 	nr_nodemap_entries = 0;
4534 }
4535 
4536 /* Compare two active node_active_regions */
cmp_node_active_region(const void * a,const void * b)4537 static int __init cmp_node_active_region(const void *a, const void *b)
4538 {
4539 	struct node_active_region *arange = (struct node_active_region *)a;
4540 	struct node_active_region *brange = (struct node_active_region *)b;
4541 
4542 	/* Done this way to avoid overflows */
4543 	if (arange->start_pfn > brange->start_pfn)
4544 		return 1;
4545 	if (arange->start_pfn < brange->start_pfn)
4546 		return -1;
4547 
4548 	return 0;
4549 }
4550 
4551 /* sort the node_map by start_pfn */
sort_node_map(void)4552 void __init sort_node_map(void)
4553 {
4554 	sort(early_node_map, (size_t)nr_nodemap_entries,
4555 			sizeof(struct node_active_region),
4556 			cmp_node_active_region, NULL);
4557 }
4558 
4559 /* Find the lowest pfn for a node */
find_min_pfn_for_node(int nid)4560 static unsigned long __init find_min_pfn_for_node(int nid)
4561 {
4562 	int i;
4563 	unsigned long min_pfn = ULONG_MAX;
4564 
4565 	/* Assuming a sorted map, the first range found has the starting pfn */
4566 	for_each_active_range_index_in_nid(i, nid)
4567 		min_pfn = min(min_pfn, early_node_map[i].start_pfn);
4568 
4569 	if (min_pfn == ULONG_MAX) {
4570 		printk(KERN_WARNING
4571 			"Could not find start_pfn for node %d\n", nid);
4572 		return 0;
4573 	}
4574 
4575 	return min_pfn;
4576 }
4577 
4578 /**
4579  * find_min_pfn_with_active_regions - Find the minimum PFN registered
4580  *
4581  * It returns the minimum PFN based on information provided via
4582  * add_active_range().
4583  */
find_min_pfn_with_active_regions(void)4584 unsigned long __init find_min_pfn_with_active_regions(void)
4585 {
4586 	return find_min_pfn_for_node(MAX_NUMNODES);
4587 }
4588 
4589 /*
4590  * early_calculate_totalpages()
4591  * Sum pages in active regions for movable zone.
4592  * Populate N_HIGH_MEMORY for calculating usable_nodes.
4593  */
early_calculate_totalpages(void)4594 static unsigned long __init early_calculate_totalpages(void)
4595 {
4596 	int i;
4597 	unsigned long totalpages = 0;
4598 
4599 	for (i = 0; i < nr_nodemap_entries; i++) {
4600 		unsigned long pages = early_node_map[i].end_pfn -
4601 						early_node_map[i].start_pfn;
4602 		totalpages += pages;
4603 		if (pages)
4604 			node_set_state(early_node_map[i].nid, N_HIGH_MEMORY);
4605 	}
4606   	return totalpages;
4607 }
4608 
4609 /*
4610  * Find the PFN the Movable zone begins in each node. Kernel memory
4611  * is spread evenly between nodes as long as the nodes have enough
4612  * memory. When they don't, some nodes will have more kernelcore than
4613  * others
4614  */
find_zone_movable_pfns_for_nodes(unsigned long * movable_pfn)4615 static void __init find_zone_movable_pfns_for_nodes(unsigned long *movable_pfn)
4616 {
4617 	int i, nid;
4618 	unsigned long usable_startpfn;
4619 	unsigned long kernelcore_node, kernelcore_remaining;
4620 	/* save the state before borrow the nodemask */
4621 	nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
4622 	unsigned long totalpages = early_calculate_totalpages();
4623 	int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
4624 
4625 	/*
4626 	 * If movablecore was specified, calculate what size of
4627 	 * kernelcore that corresponds so that memory usable for
4628 	 * any allocation type is evenly spread. If both kernelcore
4629 	 * and movablecore are specified, then the value of kernelcore
4630 	 * will be used for required_kernelcore if it's greater than
4631 	 * what movablecore would have allowed.
4632 	 */
4633 	if (required_movablecore) {
4634 		unsigned long corepages;
4635 
4636 		/*
4637 		 * Round-up so that ZONE_MOVABLE is at least as large as what
4638 		 * was requested by the user
4639 		 */
4640 		required_movablecore =
4641 			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4642 		corepages = totalpages - required_movablecore;
4643 
4644 		required_kernelcore = max(required_kernelcore, corepages);
4645 	}
4646 
4647 	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
4648 	if (!required_kernelcore)
4649 		goto out;
4650 
4651 	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4652 	find_usable_zone_for_movable();
4653 	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4654 
4655 restart:
4656 	/* Spread kernelcore memory as evenly as possible throughout nodes */
4657 	kernelcore_node = required_kernelcore / usable_nodes;
4658 	for_each_node_state(nid, N_HIGH_MEMORY) {
4659 		/*
4660 		 * Recalculate kernelcore_node if the division per node
4661 		 * now exceeds what is necessary to satisfy the requested
4662 		 * amount of memory for the kernel
4663 		 */
4664 		if (required_kernelcore < kernelcore_node)
4665 			kernelcore_node = required_kernelcore / usable_nodes;
4666 
4667 		/*
4668 		 * As the map is walked, we track how much memory is usable
4669 		 * by the kernel using kernelcore_remaining. When it is
4670 		 * 0, the rest of the node is usable by ZONE_MOVABLE
4671 		 */
4672 		kernelcore_remaining = kernelcore_node;
4673 
4674 		/* Go through each range of PFNs within this node */
4675 		for_each_active_range_index_in_nid(i, nid) {
4676 			unsigned long start_pfn, end_pfn;
4677 			unsigned long size_pages;
4678 
4679 			start_pfn = max(early_node_map[i].start_pfn,
4680 						zone_movable_pfn[nid]);
4681 			end_pfn = early_node_map[i].end_pfn;
4682 			if (start_pfn >= end_pfn)
4683 				continue;
4684 
4685 			/* Account for what is only usable for kernelcore */
4686 			if (start_pfn < usable_startpfn) {
4687 				unsigned long kernel_pages;
4688 				kernel_pages = min(end_pfn, usable_startpfn)
4689 								- start_pfn;
4690 
4691 				kernelcore_remaining -= min(kernel_pages,
4692 							kernelcore_remaining);
4693 				required_kernelcore -= min(kernel_pages,
4694 							required_kernelcore);
4695 
4696 				/* Continue if range is now fully accounted */
4697 				if (end_pfn <= usable_startpfn) {
4698 
4699 					/*
4700 					 * Push zone_movable_pfn to the end so
4701 					 * that if we have to rebalance
4702 					 * kernelcore across nodes, we will
4703 					 * not double account here
4704 					 */
4705 					zone_movable_pfn[nid] = end_pfn;
4706 					continue;
4707 				}
4708 				start_pfn = usable_startpfn;
4709 			}
4710 
4711 			/*
4712 			 * The usable PFN range for ZONE_MOVABLE is from
4713 			 * start_pfn->end_pfn. Calculate size_pages as the
4714 			 * number of pages used as kernelcore
4715 			 */
4716 			size_pages = end_pfn - start_pfn;
4717 			if (size_pages > kernelcore_remaining)
4718 				size_pages = kernelcore_remaining;
4719 			zone_movable_pfn[nid] = start_pfn + size_pages;
4720 
4721 			/*
4722 			 * Some kernelcore has been met, update counts and
4723 			 * break if the kernelcore for this node has been
4724 			 * satisified
4725 			 */
4726 			required_kernelcore -= min(required_kernelcore,
4727 								size_pages);
4728 			kernelcore_remaining -= size_pages;
4729 			if (!kernelcore_remaining)
4730 				break;
4731 		}
4732 	}
4733 
4734 	/*
4735 	 * If there is still required_kernelcore, we do another pass with one
4736 	 * less node in the count. This will push zone_movable_pfn[nid] further
4737 	 * along on the nodes that still have memory until kernelcore is
4738 	 * satisified
4739 	 */
4740 	usable_nodes--;
4741 	if (usable_nodes && required_kernelcore > usable_nodes)
4742 		goto restart;
4743 
4744 	/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
4745 	for (nid = 0; nid < MAX_NUMNODES; nid++)
4746 		zone_movable_pfn[nid] =
4747 			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
4748 
4749 out:
4750 	/* restore the node_state */
4751 	node_states[N_HIGH_MEMORY] = saved_node_state;
4752 }
4753 
4754 /* Any regular memory on that node ? */
check_for_regular_memory(pg_data_t * pgdat)4755 static void check_for_regular_memory(pg_data_t *pgdat)
4756 {
4757 #ifdef CONFIG_HIGHMEM
4758 	enum zone_type zone_type;
4759 
4760 	for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
4761 		struct zone *zone = &pgdat->node_zones[zone_type];
4762 		if (zone->present_pages)
4763 			node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
4764 	}
4765 #endif
4766 }
4767 
4768 /**
4769  * free_area_init_nodes - Initialise all pg_data_t and zone data
4770  * @max_zone_pfn: an array of max PFNs for each zone
4771  *
4772  * This will call free_area_init_node() for each active node in the system.
4773  * Using the page ranges provided by add_active_range(), the size of each
4774  * zone in each node and their holes is calculated. If the maximum PFN
4775  * between two adjacent zones match, it is assumed that the zone is empty.
4776  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
4777  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
4778  * starts where the previous one ended. For example, ZONE_DMA32 starts
4779  * at arch_max_dma_pfn.
4780  */
free_area_init_nodes(unsigned long * max_zone_pfn)4781 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
4782 {
4783 	unsigned long nid;
4784 	int i;
4785 
4786 	/* Sort early_node_map as initialisation assumes it is sorted */
4787 	sort_node_map();
4788 
4789 	/* Record where the zone boundaries are */
4790 	memset(arch_zone_lowest_possible_pfn, 0,
4791 				sizeof(arch_zone_lowest_possible_pfn));
4792 	memset(arch_zone_highest_possible_pfn, 0,
4793 				sizeof(arch_zone_highest_possible_pfn));
4794 	arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
4795 	arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
4796 	for (i = 1; i < MAX_NR_ZONES; i++) {
4797 		if (i == ZONE_MOVABLE)
4798 			continue;
4799 		arch_zone_lowest_possible_pfn[i] =
4800 			arch_zone_highest_possible_pfn[i-1];
4801 		arch_zone_highest_possible_pfn[i] =
4802 			max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
4803 	}
4804 	arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
4805 	arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
4806 
4807 	/* Find the PFNs that ZONE_MOVABLE begins at in each node */
4808 	memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
4809 	find_zone_movable_pfns_for_nodes(zone_movable_pfn);
4810 
4811 	/* Print out the zone ranges */
4812 	printk("Zone PFN ranges:\n");
4813 	for (i = 0; i < MAX_NR_ZONES; i++) {
4814 		if (i == ZONE_MOVABLE)
4815 			continue;
4816 		printk("  %-8s ", zone_names[i]);
4817 		if (arch_zone_lowest_possible_pfn[i] ==
4818 				arch_zone_highest_possible_pfn[i])
4819 			printk("empty\n");
4820 		else
4821 			printk("%0#10lx -> %0#10lx\n",
4822 				arch_zone_lowest_possible_pfn[i],
4823 				arch_zone_highest_possible_pfn[i]);
4824 	}
4825 
4826 	/* Print out the PFNs ZONE_MOVABLE begins at in each node */
4827 	printk("Movable zone start PFN for each node\n");
4828 	for (i = 0; i < MAX_NUMNODES; i++) {
4829 		if (zone_movable_pfn[i])
4830 			printk("  Node %d: %lu\n", i, zone_movable_pfn[i]);
4831 	}
4832 
4833 	/* Print out the early_node_map[] */
4834 	printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
4835 	for (i = 0; i < nr_nodemap_entries; i++)
4836 		printk("  %3d: %0#10lx -> %0#10lx\n", early_node_map[i].nid,
4837 						early_node_map[i].start_pfn,
4838 						early_node_map[i].end_pfn);
4839 
4840 	/* Initialise every node */
4841 	mminit_verify_pageflags_layout();
4842 	setup_nr_node_ids();
4843 	for_each_online_node(nid) {
4844 		pg_data_t *pgdat = NODE_DATA(nid);
4845 		free_area_init_node(nid, NULL,
4846 				find_min_pfn_for_node(nid), NULL);
4847 
4848 		/* Any memory on that node */
4849 		if (pgdat->node_present_pages)
4850 			node_set_state(nid, N_HIGH_MEMORY);
4851 		check_for_regular_memory(pgdat);
4852 	}
4853 }
4854 
cmdline_parse_core(char * p,unsigned long * core)4855 static int __init cmdline_parse_core(char *p, unsigned long *core)
4856 {
4857 	unsigned long long coremem;
4858 	if (!p)
4859 		return -EINVAL;
4860 
4861 	coremem = memparse(p, &p);
4862 	*core = coremem >> PAGE_SHIFT;
4863 
4864 	/* Paranoid check that UL is enough for the coremem value */
4865 	WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
4866 
4867 	return 0;
4868 }
4869 
4870 /*
4871  * kernelcore=size sets the amount of memory for use for allocations that
4872  * cannot be reclaimed or migrated.
4873  */
cmdline_parse_kernelcore(char * p)4874 static int __init cmdline_parse_kernelcore(char *p)
4875 {
4876 	return cmdline_parse_core(p, &required_kernelcore);
4877 }
4878 
4879 /*
4880  * movablecore=size sets the amount of memory for use for allocations that
4881  * can be reclaimed or migrated.
4882  */
cmdline_parse_movablecore(char * p)4883 static int __init cmdline_parse_movablecore(char *p)
4884 {
4885 	return cmdline_parse_core(p, &required_movablecore);
4886 }
4887 
4888 early_param("kernelcore", cmdline_parse_kernelcore);
4889 early_param("movablecore", cmdline_parse_movablecore);
4890 
4891 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4892 
4893 /**
4894  * set_dma_reserve - set the specified number of pages reserved in the first zone
4895  * @new_dma_reserve: The number of pages to mark reserved
4896  *
4897  * The per-cpu batchsize and zone watermarks are determined by present_pages.
4898  * In the DMA zone, a significant percentage may be consumed by kernel image
4899  * and other unfreeable allocations which can skew the watermarks badly. This
4900  * function may optionally be used to account for unfreeable pages in the
4901  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
4902  * smaller per-cpu batchsize.
4903  */
set_dma_reserve(unsigned long new_dma_reserve)4904 void __init set_dma_reserve(unsigned long new_dma_reserve)
4905 {
4906 	dma_reserve = new_dma_reserve;
4907 }
4908 
free_area_init(unsigned long * zones_size)4909 void __init free_area_init(unsigned long *zones_size)
4910 {
4911 	free_area_init_node(0, zones_size,
4912 			__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
4913 }
4914 
page_alloc_cpu_notify(struct notifier_block * self,unsigned long action,void * hcpu)4915 static int page_alloc_cpu_notify(struct notifier_block *self,
4916 				 unsigned long action, void *hcpu)
4917 {
4918 	int cpu = (unsigned long)hcpu;
4919 
4920 	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
4921 		drain_pages(cpu);
4922 
4923 		/*
4924 		 * Spill the event counters of the dead processor
4925 		 * into the current processors event counters.
4926 		 * This artificially elevates the count of the current
4927 		 * processor.
4928 		 */
4929 		vm_events_fold_cpu(cpu);
4930 
4931 		/*
4932 		 * Zero the differential counters of the dead processor
4933 		 * so that the vm statistics are consistent.
4934 		 *
4935 		 * This is only okay since the processor is dead and cannot
4936 		 * race with what we are doing.
4937 		 */
4938 		refresh_cpu_vm_stats(cpu);
4939 	}
4940 	return NOTIFY_OK;
4941 }
4942 
page_alloc_init(void)4943 void __init page_alloc_init(void)
4944 {
4945 	hotcpu_notifier(page_alloc_cpu_notify, 0);
4946 }
4947 
4948 /*
4949  * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
4950  *	or min_free_kbytes changes.
4951  */
calculate_totalreserve_pages(void)4952 static void calculate_totalreserve_pages(void)
4953 {
4954 	struct pglist_data *pgdat;
4955 	unsigned long reserve_pages = 0;
4956 	enum zone_type i, j;
4957 
4958 	for_each_online_pgdat(pgdat) {
4959 		for (i = 0; i < MAX_NR_ZONES; i++) {
4960 			struct zone *zone = pgdat->node_zones + i;
4961 			unsigned long max = 0;
4962 
4963 			/* Find valid and maximum lowmem_reserve in the zone */
4964 			for (j = i; j < MAX_NR_ZONES; j++) {
4965 				if (zone->lowmem_reserve[j] > max)
4966 					max = zone->lowmem_reserve[j];
4967 			}
4968 
4969 			/* we treat the high watermark as reserved pages. */
4970 			max += high_wmark_pages(zone);
4971 
4972 			if (max > zone->present_pages)
4973 				max = zone->present_pages;
4974 			reserve_pages += max;
4975 		}
4976 	}
4977 	totalreserve_pages = reserve_pages;
4978 }
4979 
4980 /*
4981  * setup_per_zone_lowmem_reserve - called whenever
4982  *	sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
4983  *	has a correct pages reserved value, so an adequate number of
4984  *	pages are left in the zone after a successful __alloc_pages().
4985  */
setup_per_zone_lowmem_reserve(void)4986 static void setup_per_zone_lowmem_reserve(void)
4987 {
4988 	struct pglist_data *pgdat;
4989 	enum zone_type j, idx;
4990 
4991 	for_each_online_pgdat(pgdat) {
4992 		for (j = 0; j < MAX_NR_ZONES; j++) {
4993 			struct zone *zone = pgdat->node_zones + j;
4994 			unsigned long present_pages = zone->present_pages;
4995 
4996 			zone->lowmem_reserve[j] = 0;
4997 
4998 			idx = j;
4999 			while (idx) {
5000 				struct zone *lower_zone;
5001 
5002 				idx--;
5003 
5004 				if (sysctl_lowmem_reserve_ratio[idx] < 1)
5005 					sysctl_lowmem_reserve_ratio[idx] = 1;
5006 
5007 				lower_zone = pgdat->node_zones + idx;
5008 				lower_zone->lowmem_reserve[j] = present_pages /
5009 					sysctl_lowmem_reserve_ratio[idx];
5010 				present_pages += lower_zone->present_pages;
5011 			}
5012 		}
5013 	}
5014 
5015 	/* update totalreserve_pages */
5016 	calculate_totalreserve_pages();
5017 }
5018 
5019 /**
5020  * setup_per_zone_wmarks - called when min_free_kbytes changes
5021  * or when memory is hot-{added|removed}
5022  *
5023  * Ensures that the watermark[min,low,high] values for each zone are set
5024  * correctly with respect to min_free_kbytes.
5025  */
setup_per_zone_wmarks(void)5026 void setup_per_zone_wmarks(void)
5027 {
5028 	unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5029 	unsigned long lowmem_pages = 0;
5030 	struct zone *zone;
5031 	unsigned long flags;
5032 
5033 	/* Calculate total number of !ZONE_HIGHMEM pages */
5034 	for_each_zone(zone) {
5035 		if (!is_highmem(zone))
5036 			lowmem_pages += zone->present_pages;
5037 	}
5038 
5039 	for_each_zone(zone) {
5040 		u64 tmp;
5041 
5042 		spin_lock_irqsave(&zone->lock, flags);
5043 		tmp = (u64)pages_min * zone->present_pages;
5044 		do_div(tmp, lowmem_pages);
5045 		if (is_highmem(zone)) {
5046 			/*
5047 			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5048 			 * need highmem pages, so cap pages_min to a small
5049 			 * value here.
5050 			 *
5051 			 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5052 			 * deltas controls asynch page reclaim, and so should
5053 			 * not be capped for highmem.
5054 			 */
5055 			int min_pages;
5056 
5057 			min_pages = zone->present_pages / 1024;
5058 			if (min_pages < SWAP_CLUSTER_MAX)
5059 				min_pages = SWAP_CLUSTER_MAX;
5060 			if (min_pages > 128)
5061 				min_pages = 128;
5062 			zone->watermark[WMARK_MIN] = min_pages;
5063 		} else {
5064 			/*
5065 			 * If it's a lowmem zone, reserve a number of pages
5066 			 * proportionate to the zone's size.
5067 			 */
5068 			zone->watermark[WMARK_MIN] = tmp;
5069 		}
5070 
5071 		zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);
5072 		zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5073 		setup_zone_migrate_reserve(zone);
5074 		spin_unlock_irqrestore(&zone->lock, flags);
5075 	}
5076 
5077 	/* update totalreserve_pages */
5078 	calculate_totalreserve_pages();
5079 }
5080 
5081 /*
5082  * The inactive anon list should be small enough that the VM never has to
5083  * do too much work, but large enough that each inactive page has a chance
5084  * to be referenced again before it is swapped out.
5085  *
5086  * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5087  * INACTIVE_ANON pages on this zone's LRU, maintained by the
5088  * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5089  * the anonymous pages are kept on the inactive list.
5090  *
5091  * total     target    max
5092  * memory    ratio     inactive anon
5093  * -------------------------------------
5094  *   10MB       1         5MB
5095  *  100MB       1        50MB
5096  *    1GB       3       250MB
5097  *   10GB      10       0.9GB
5098  *  100GB      31         3GB
5099  *    1TB     101        10GB
5100  *   10TB     320        32GB
5101  */
calculate_zone_inactive_ratio(struct zone * zone)5102 void calculate_zone_inactive_ratio(struct zone *zone)
5103 {
5104 	unsigned int gb, ratio;
5105 
5106 	/* Zone size in gigabytes */
5107 	gb = zone->present_pages >> (30 - PAGE_SHIFT);
5108 	if (gb)
5109 		ratio = int_sqrt(10 * gb);
5110 	else
5111 		ratio = 1;
5112 
5113 	zone->inactive_ratio = ratio;
5114 }
5115 
setup_per_zone_inactive_ratio(void)5116 static void __init setup_per_zone_inactive_ratio(void)
5117 {
5118 	struct zone *zone;
5119 
5120 	for_each_zone(zone)
5121 		calculate_zone_inactive_ratio(zone);
5122 }
5123 
5124 /*
5125  * Initialise min_free_kbytes.
5126  *
5127  * For small machines we want it small (128k min).  For large machines
5128  * we want it large (64MB max).  But it is not linear, because network
5129  * bandwidth does not increase linearly with machine size.  We use
5130  *
5131  * 	min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5132  *	min_free_kbytes = sqrt(lowmem_kbytes * 16)
5133  *
5134  * which yields
5135  *
5136  * 16MB:	512k
5137  * 32MB:	724k
5138  * 64MB:	1024k
5139  * 128MB:	1448k
5140  * 256MB:	2048k
5141  * 512MB:	2896k
5142  * 1024MB:	4096k
5143  * 2048MB:	5792k
5144  * 4096MB:	8192k
5145  * 8192MB:	11584k
5146  * 16384MB:	16384k
5147  */
init_per_zone_wmark_min(void)5148 static int __init init_per_zone_wmark_min(void)
5149 {
5150 	unsigned long lowmem_kbytes;
5151 
5152 	lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5153 
5154 	min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5155 	if (min_free_kbytes < 128)
5156 		min_free_kbytes = 128;
5157 	if (min_free_kbytes > 65536)
5158 		min_free_kbytes = 65536;
5159 	setup_per_zone_wmarks();
5160 	setup_per_zone_lowmem_reserve();
5161 	setup_per_zone_inactive_ratio();
5162 	return 0;
5163 }
module_init(init_per_zone_wmark_min)5164 module_init(init_per_zone_wmark_min)
5165 
5166 /*
5167  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5168  *	that we can call two helper functions whenever min_free_kbytes
5169  *	changes.
5170  */
5171 int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5172 	void __user *buffer, size_t *length, loff_t *ppos)
5173 {
5174 	proc_dointvec(table, write, buffer, length, ppos);
5175 	if (write)
5176 		setup_per_zone_wmarks();
5177 	return 0;
5178 }
5179 
5180 #ifdef CONFIG_NUMA
sysctl_min_unmapped_ratio_sysctl_handler(ctl_table * table,int write,void __user * buffer,size_t * length,loff_t * ppos)5181 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5182 	void __user *buffer, size_t *length, loff_t *ppos)
5183 {
5184 	struct zone *zone;
5185 	int rc;
5186 
5187 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5188 	if (rc)
5189 		return rc;
5190 
5191 	for_each_zone(zone)
5192 		zone->min_unmapped_pages = (zone->present_pages *
5193 				sysctl_min_unmapped_ratio) / 100;
5194 	return 0;
5195 }
5196 
sysctl_min_slab_ratio_sysctl_handler(ctl_table * table,int write,void __user * buffer,size_t * length,loff_t * ppos)5197 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5198 	void __user *buffer, size_t *length, loff_t *ppos)
5199 {
5200 	struct zone *zone;
5201 	int rc;
5202 
5203 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5204 	if (rc)
5205 		return rc;
5206 
5207 	for_each_zone(zone)
5208 		zone->min_slab_pages = (zone->present_pages *
5209 				sysctl_min_slab_ratio) / 100;
5210 	return 0;
5211 }
5212 #endif
5213 
5214 /*
5215  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5216  *	proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5217  *	whenever sysctl_lowmem_reserve_ratio changes.
5218  *
5219  * The reserve ratio obviously has absolutely no relation with the
5220  * minimum watermarks. The lowmem reserve ratio can only make sense
5221  * if in function of the boot time zone sizes.
5222  */
lowmem_reserve_ratio_sysctl_handler(ctl_table * table,int write,void __user * buffer,size_t * length,loff_t * ppos)5223 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5224 	void __user *buffer, size_t *length, loff_t *ppos)
5225 {
5226 	proc_dointvec_minmax(table, write, buffer, length, ppos);
5227 	setup_per_zone_lowmem_reserve();
5228 	return 0;
5229 }
5230 
5231 /*
5232  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5233  * cpu.  It is the fraction of total pages in each zone that a hot per cpu pagelist
5234  * can have before it gets flushed back to buddy allocator.
5235  */
5236 
percpu_pagelist_fraction_sysctl_handler(ctl_table * table,int write,void __user * buffer,size_t * length,loff_t * ppos)5237 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5238 	void __user *buffer, size_t *length, loff_t *ppos)
5239 {
5240 	struct zone *zone;
5241 	unsigned int cpu;
5242 	int ret;
5243 
5244 	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5245 	if (!write || (ret == -EINVAL))
5246 		return ret;
5247 	for_each_populated_zone(zone) {
5248 		for_each_possible_cpu(cpu) {
5249 			unsigned long  high;
5250 			high = zone->present_pages / percpu_pagelist_fraction;
5251 			setup_pagelist_highmark(
5252 				per_cpu_ptr(zone->pageset, cpu), high);
5253 		}
5254 	}
5255 	return 0;
5256 }
5257 
5258 int hashdist = HASHDIST_DEFAULT;
5259 
5260 #ifdef CONFIG_NUMA
set_hashdist(char * str)5261 static int __init set_hashdist(char *str)
5262 {
5263 	if (!str)
5264 		return 0;
5265 	hashdist = simple_strtoul(str, &str, 0);
5266 	return 1;
5267 }
5268 __setup("hashdist=", set_hashdist);
5269 #endif
5270 
5271 /*
5272  * allocate a large system hash table from bootmem
5273  * - it is assumed that the hash table must contain an exact power-of-2
5274  *   quantity of entries
5275  * - limit is the number of hash buckets, not the total allocation size
5276  */
alloc_large_system_hash(const char * tablename,unsigned long bucketsize,unsigned long numentries,int scale,int flags,unsigned int * _hash_shift,unsigned int * _hash_mask,unsigned long limit)5277 void *__init alloc_large_system_hash(const char *tablename,
5278 				     unsigned long bucketsize,
5279 				     unsigned long numentries,
5280 				     int scale,
5281 				     int flags,
5282 				     unsigned int *_hash_shift,
5283 				     unsigned int *_hash_mask,
5284 				     unsigned long limit)
5285 {
5286 	unsigned long long max = limit;
5287 	unsigned long log2qty, size;
5288 	void *table = NULL;
5289 
5290 	/* allow the kernel cmdline to have a say */
5291 	if (!numentries) {
5292 		/* round applicable memory size up to nearest megabyte */
5293 		numentries = nr_kernel_pages;
5294 		numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5295 		numentries >>= 20 - PAGE_SHIFT;
5296 		numentries <<= 20 - PAGE_SHIFT;
5297 
5298 		/* limit to 1 bucket per 2^scale bytes of low memory */
5299 		if (scale > PAGE_SHIFT)
5300 			numentries >>= (scale - PAGE_SHIFT);
5301 		else
5302 			numentries <<= (PAGE_SHIFT - scale);
5303 
5304 		/* Make sure we've got at least a 0-order allocation.. */
5305 		if (unlikely(flags & HASH_SMALL)) {
5306 			/* Makes no sense without HASH_EARLY */
5307 			WARN_ON(!(flags & HASH_EARLY));
5308 			if (!(numentries >> *_hash_shift)) {
5309 				numentries = 1UL << *_hash_shift;
5310 				BUG_ON(!numentries);
5311 			}
5312 		} else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5313 			numentries = PAGE_SIZE / bucketsize;
5314 	}
5315 	numentries = roundup_pow_of_two(numentries);
5316 
5317 	/* limit allocation size to 1/16 total memory by default */
5318 	if (max == 0) {
5319 		max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5320 		do_div(max, bucketsize);
5321 	}
5322 
5323 	if (numentries > max)
5324 		numentries = max;
5325 
5326 	log2qty = ilog2(numentries);
5327 
5328 	do {
5329 		size = bucketsize << log2qty;
5330 		if (flags & HASH_EARLY)
5331 			table = alloc_bootmem_nopanic(size);
5332 		else if (hashdist)
5333 			table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5334 		else {
5335 			/*
5336 			 * If bucketsize is not a power-of-two, we may free
5337 			 * some pages at the end of hash table which
5338 			 * alloc_pages_exact() automatically does
5339 			 */
5340 			if (get_order(size) < MAX_ORDER) {
5341 				table = alloc_pages_exact(size, GFP_ATOMIC);
5342 				kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5343 			}
5344 		}
5345 	} while (!table && size > PAGE_SIZE && --log2qty);
5346 
5347 	if (!table)
5348 		panic("Failed to allocate %s hash table\n", tablename);
5349 
5350 	printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5351 	       tablename,
5352 	       (1UL << log2qty),
5353 	       ilog2(size) - PAGE_SHIFT,
5354 	       size);
5355 
5356 	if (_hash_shift)
5357 		*_hash_shift = log2qty;
5358 	if (_hash_mask)
5359 		*_hash_mask = (1 << log2qty) - 1;
5360 
5361 	return table;
5362 }
5363 
5364 /* Return a pointer to the bitmap storing bits affecting a block of pages */
get_pageblock_bitmap(struct zone * zone,unsigned long pfn)5365 static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5366 							unsigned long pfn)
5367 {
5368 #ifdef CONFIG_SPARSEMEM
5369 	return __pfn_to_section(pfn)->pageblock_flags;
5370 #else
5371 	return zone->pageblock_flags;
5372 #endif /* CONFIG_SPARSEMEM */
5373 }
5374 
pfn_to_bitidx(struct zone * zone,unsigned long pfn)5375 static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5376 {
5377 #ifdef CONFIG_SPARSEMEM
5378 	pfn &= (PAGES_PER_SECTION-1);
5379 	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5380 #else
5381 	pfn = pfn - zone->zone_start_pfn;
5382 	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5383 #endif /* CONFIG_SPARSEMEM */
5384 }
5385 
5386 /**
5387  * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
5388  * @page: The page within the block of interest
5389  * @start_bitidx: The first bit of interest to retrieve
5390  * @end_bitidx: The last bit of interest
5391  * returns pageblock_bits flags
5392  */
get_pageblock_flags_group(struct page * page,int start_bitidx,int end_bitidx)5393 unsigned long get_pageblock_flags_group(struct page *page,
5394 					int start_bitidx, int end_bitidx)
5395 {
5396 	struct zone *zone;
5397 	unsigned long *bitmap;
5398 	unsigned long pfn, bitidx;
5399 	unsigned long flags = 0;
5400 	unsigned long value = 1;
5401 
5402 	zone = page_zone(page);
5403 	pfn = page_to_pfn(page);
5404 	bitmap = get_pageblock_bitmap(zone, pfn);
5405 	bitidx = pfn_to_bitidx(zone, pfn);
5406 
5407 	for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5408 		if (test_bit(bitidx + start_bitidx, bitmap))
5409 			flags |= value;
5410 
5411 	return flags;
5412 }
5413 
5414 /**
5415  * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
5416  * @page: The page within the block of interest
5417  * @start_bitidx: The first bit of interest
5418  * @end_bitidx: The last bit of interest
5419  * @flags: The flags to set
5420  */
set_pageblock_flags_group(struct page * page,unsigned long flags,int start_bitidx,int end_bitidx)5421 void set_pageblock_flags_group(struct page *page, unsigned long flags,
5422 					int start_bitidx, int end_bitidx)
5423 {
5424 	struct zone *zone;
5425 	unsigned long *bitmap;
5426 	unsigned long pfn, bitidx;
5427 	unsigned long value = 1;
5428 
5429 	zone = page_zone(page);
5430 	pfn = page_to_pfn(page);
5431 	bitmap = get_pageblock_bitmap(zone, pfn);
5432 	bitidx = pfn_to_bitidx(zone, pfn);
5433 	VM_BUG_ON(pfn < zone->zone_start_pfn);
5434 	VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
5435 
5436 	for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5437 		if (flags & value)
5438 			__set_bit(bitidx + start_bitidx, bitmap);
5439 		else
5440 			__clear_bit(bitidx + start_bitidx, bitmap);
5441 }
5442 
5443 /*
5444  * This is designed as sub function...plz see page_isolation.c also.
5445  * set/clear page block's type to be ISOLATE.
5446  * page allocater never alloc memory from ISOLATE block.
5447  */
5448 
5449 static int
__count_immobile_pages(struct zone * zone,struct page * page,int count)5450 __count_immobile_pages(struct zone *zone, struct page *page, int count)
5451 {
5452 	unsigned long pfn, iter, found;
5453 	/*
5454 	 * For avoiding noise data, lru_add_drain_all() should be called
5455 	 * If ZONE_MOVABLE, the zone never contains immobile pages
5456 	 */
5457 	if (zone_idx(zone) == ZONE_MOVABLE)
5458 		return true;
5459 
5460 	if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE)
5461 		return true;
5462 
5463 	pfn = page_to_pfn(page);
5464 	for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
5465 		unsigned long check = pfn + iter;
5466 
5467 		if (!pfn_valid_within(check))
5468 			continue;
5469 
5470 		page = pfn_to_page(check);
5471 		if (!page_count(page)) {
5472 			if (PageBuddy(page))
5473 				iter += (1 << page_order(page)) - 1;
5474 			continue;
5475 		}
5476 		if (!PageLRU(page))
5477 			found++;
5478 		/*
5479 		 * If there are RECLAIMABLE pages, we need to check it.
5480 		 * But now, memory offline itself doesn't call shrink_slab()
5481 		 * and it still to be fixed.
5482 		 */
5483 		/*
5484 		 * If the page is not RAM, page_count()should be 0.
5485 		 * we don't need more check. This is an _used_ not-movable page.
5486 		 *
5487 		 * The problematic thing here is PG_reserved pages. PG_reserved
5488 		 * is set to both of a memory hole page and a _used_ kernel
5489 		 * page at boot.
5490 		 */
5491 		if (found > count)
5492 			return false;
5493 	}
5494 	return true;
5495 }
5496 
is_pageblock_removable_nolock(struct page * page)5497 bool is_pageblock_removable_nolock(struct page *page)
5498 {
5499 	struct zone *zone = page_zone(page);
5500 	return __count_immobile_pages(zone, page, 0);
5501 }
5502 
set_migratetype_isolate(struct page * page)5503 int set_migratetype_isolate(struct page *page)
5504 {
5505 	struct zone *zone;
5506 	unsigned long flags, pfn;
5507 	struct memory_isolate_notify arg;
5508 	int notifier_ret;
5509 	int ret = -EBUSY;
5510 	int zone_idx;
5511 
5512 	zone = page_zone(page);
5513 	zone_idx = zone_idx(zone);
5514 
5515 	spin_lock_irqsave(&zone->lock, flags);
5516 
5517 	pfn = page_to_pfn(page);
5518 	arg.start_pfn = pfn;
5519 	arg.nr_pages = pageblock_nr_pages;
5520 	arg.pages_found = 0;
5521 
5522 	/*
5523 	 * It may be possible to isolate a pageblock even if the
5524 	 * migratetype is not MIGRATE_MOVABLE. The memory isolation
5525 	 * notifier chain is used by balloon drivers to return the
5526 	 * number of pages in a range that are held by the balloon
5527 	 * driver to shrink memory. If all the pages are accounted for
5528 	 * by balloons, are free, or on the LRU, isolation can continue.
5529 	 * Later, for example, when memory hotplug notifier runs, these
5530 	 * pages reported as "can be isolated" should be isolated(freed)
5531 	 * by the balloon driver through the memory notifier chain.
5532 	 */
5533 	notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
5534 	notifier_ret = notifier_to_errno(notifier_ret);
5535 	if (notifier_ret)
5536 		goto out;
5537 	/*
5538 	 * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
5539 	 * We just check MOVABLE pages.
5540 	 */
5541 	if (__count_immobile_pages(zone, page, arg.pages_found))
5542 		ret = 0;
5543 
5544 	/*
5545 	 * immobile means "not-on-lru" paes. If immobile is larger than
5546 	 * removable-by-driver pages reported by notifier, we'll fail.
5547 	 */
5548 
5549 out:
5550 	if (!ret) {
5551 		set_pageblock_migratetype(page, MIGRATE_ISOLATE);
5552 		move_freepages_block(zone, page, MIGRATE_ISOLATE);
5553 	}
5554 
5555 	spin_unlock_irqrestore(&zone->lock, flags);
5556 	if (!ret)
5557 		drain_all_pages();
5558 	return ret;
5559 }
5560 
unset_migratetype_isolate(struct page * page)5561 void unset_migratetype_isolate(struct page *page)
5562 {
5563 	struct zone *zone;
5564 	unsigned long flags;
5565 	zone = page_zone(page);
5566 	spin_lock_irqsave(&zone->lock, flags);
5567 	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
5568 		goto out;
5569 	set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5570 	move_freepages_block(zone, page, MIGRATE_MOVABLE);
5571 out:
5572 	spin_unlock_irqrestore(&zone->lock, flags);
5573 }
5574 
5575 #ifdef CONFIG_MEMORY_HOTREMOVE
5576 /*
5577  * All pages in the range must be isolated before calling this.
5578  */
5579 void
__offline_isolated_pages(unsigned long start_pfn,unsigned long end_pfn)5580 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
5581 {
5582 	struct page *page;
5583 	struct zone *zone;
5584 	int order, i;
5585 	unsigned long pfn;
5586 	unsigned long flags;
5587 	/* find the first valid pfn */
5588 	for (pfn = start_pfn; pfn < end_pfn; pfn++)
5589 		if (pfn_valid(pfn))
5590 			break;
5591 	if (pfn == end_pfn)
5592 		return;
5593 	zone = page_zone(pfn_to_page(pfn));
5594 	spin_lock_irqsave(&zone->lock, flags);
5595 	pfn = start_pfn;
5596 	while (pfn < end_pfn) {
5597 		if (!pfn_valid(pfn)) {
5598 			pfn++;
5599 			continue;
5600 		}
5601 		page = pfn_to_page(pfn);
5602 		BUG_ON(page_count(page));
5603 		BUG_ON(!PageBuddy(page));
5604 		order = page_order(page);
5605 #ifdef CONFIG_DEBUG_VM
5606 		printk(KERN_INFO "remove from free list %lx %d %lx\n",
5607 		       pfn, 1 << order, end_pfn);
5608 #endif
5609 		list_del(&page->lru);
5610 		rmv_page_order(page);
5611 		zone->free_area[order].nr_free--;
5612 		__mod_zone_page_state(zone, NR_FREE_PAGES,
5613 				      - (1UL << order));
5614 		for (i = 0; i < (1 << order); i++)
5615 			SetPageReserved((page+i));
5616 		pfn += (1 << order);
5617 	}
5618 	spin_unlock_irqrestore(&zone->lock, flags);
5619 }
5620 #endif
5621 
5622 #ifdef CONFIG_MEMORY_FAILURE
is_free_buddy_page(struct page * page)5623 bool is_free_buddy_page(struct page *page)
5624 {
5625 	struct zone *zone = page_zone(page);
5626 	unsigned long pfn = page_to_pfn(page);
5627 	unsigned long flags;
5628 	int order;
5629 
5630 	spin_lock_irqsave(&zone->lock, flags);
5631 	for (order = 0; order < MAX_ORDER; order++) {
5632 		struct page *page_head = page - (pfn & ((1 << order) - 1));
5633 
5634 		if (PageBuddy(page_head) && page_order(page_head) >= order)
5635 			break;
5636 	}
5637 	spin_unlock_irqrestore(&zone->lock, flags);
5638 
5639 	return order < MAX_ORDER;
5640 }
5641 #endif
5642 
5643 static struct trace_print_flags pageflag_names[] = {
5644 	{1UL << PG_locked,		"locked"	},
5645 	{1UL << PG_error,		"error"		},
5646 	{1UL << PG_referenced,		"referenced"	},
5647 	{1UL << PG_uptodate,		"uptodate"	},
5648 	{1UL << PG_dirty,		"dirty"		},
5649 	{1UL << PG_lru,			"lru"		},
5650 	{1UL << PG_active,		"active"	},
5651 	{1UL << PG_slab,		"slab"		},
5652 	{1UL << PG_owner_priv_1,	"owner_priv_1"	},
5653 	{1UL << PG_arch_1,		"arch_1"	},
5654 	{1UL << PG_reserved,		"reserved"	},
5655 	{1UL << PG_private,		"private"	},
5656 	{1UL << PG_private_2,		"private_2"	},
5657 	{1UL << PG_writeback,		"writeback"	},
5658 #ifdef CONFIG_PAGEFLAGS_EXTENDED
5659 	{1UL << PG_head,		"head"		},
5660 	{1UL << PG_tail,		"tail"		},
5661 #else
5662 	{1UL << PG_compound,		"compound"	},
5663 #endif
5664 	{1UL << PG_swapcache,		"swapcache"	},
5665 	{1UL << PG_mappedtodisk,	"mappedtodisk"	},
5666 	{1UL << PG_reclaim,		"reclaim"	},
5667 	{1UL << PG_swapbacked,		"swapbacked"	},
5668 	{1UL << PG_unevictable,		"unevictable"	},
5669 #ifdef CONFIG_MMU
5670 	{1UL << PG_mlocked,		"mlocked"	},
5671 #endif
5672 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
5673 	{1UL << PG_uncached,		"uncached"	},
5674 #endif
5675 #ifdef CONFIG_MEMORY_FAILURE
5676 	{1UL << PG_hwpoison,		"hwpoison"	},
5677 #endif
5678 	{-1UL,				NULL		},
5679 };
5680 
dump_page_flags(unsigned long flags)5681 static void dump_page_flags(unsigned long flags)
5682 {
5683 	const char *delim = "";
5684 	unsigned long mask;
5685 	int i;
5686 
5687 	printk(KERN_ALERT "page flags: %#lx(", flags);
5688 
5689 	/* remove zone id */
5690 	flags &= (1UL << NR_PAGEFLAGS) - 1;
5691 
5692 	for (i = 0; pageflag_names[i].name && flags; i++) {
5693 
5694 		mask = pageflag_names[i].mask;
5695 		if ((flags & mask) != mask)
5696 			continue;
5697 
5698 		flags &= ~mask;
5699 		printk("%s%s", delim, pageflag_names[i].name);
5700 		delim = "|";
5701 	}
5702 
5703 	/* check for left over flags */
5704 	if (flags)
5705 		printk("%s%#lx", delim, flags);
5706 
5707 	printk(")\n");
5708 }
5709 
dump_page(struct page * page)5710 void dump_page(struct page *page)
5711 {
5712 	printk(KERN_ALERT
5713 	       "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
5714 		page, atomic_read(&page->_count), page_mapcount(page),
5715 		page->mapping, page->index);
5716 	dump_page_flags(page->flags);
5717 	mem_cgroup_print_bad_page(page);
5718 }
5719