1 #ifndef LINUX_QUICKLIST_H
2 #define LINUX_QUICKLIST_H
3 /*
4 * Fast allocations and disposal of pages. Pages must be in the condition
5 * as needed after allocation when they are freed. Per cpu lists of pages
6 * are kept that only contain node local pages.
7 *
8 * (C) 2007, SGI. Christoph Lameter <clameter@sgi.com>
9 */
10 #include <linux/kernel.h>
11 #include <linux/gfp.h>
12 #include <linux/percpu.h>
13
14 #ifdef CONFIG_QUICKLIST
15
16 struct quicklist {
17 void *page;
18 int nr_pages;
19 };
20
21 DECLARE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
22
23 /*
24 * The two key functions quicklist_alloc and quicklist_free are inline so
25 * that they may be custom compiled for the platform.
26 * Specifying a NULL ctor can remove constructor support. Specifying
27 * a constant quicklist allows the determination of the exact address
28 * in the per cpu area.
29 *
30 * The fast patch in quicklist_alloc touched only a per cpu cacheline and
31 * the first cacheline of the page itself. There is minmal overhead involved.
32 */
quicklist_alloc(int nr,gfp_t flags,void (* ctor)(void *))33 static inline void *quicklist_alloc(int nr, gfp_t flags, void (*ctor)(void *))
34 {
35 struct quicklist *q;
36 void **p = NULL;
37
38 q =&get_cpu_var(quicklist)[nr];
39 p = q->page;
40 if (likely(p)) {
41 q->page = p[0];
42 p[0] = NULL;
43 q->nr_pages--;
44 }
45 put_cpu_var(quicklist);
46 if (likely(p))
47 return p;
48
49 p = (void *)__get_free_page(flags | __GFP_ZERO);
50 if (ctor && p)
51 ctor(p);
52 return p;
53 }
54
__quicklist_free(int nr,void (* dtor)(void *),void * p,struct page * page)55 static inline void __quicklist_free(int nr, void (*dtor)(void *), void *p,
56 struct page *page)
57 {
58 struct quicklist *q;
59
60 q = &get_cpu_var(quicklist)[nr];
61 *(void **)p = q->page;
62 q->page = p;
63 q->nr_pages++;
64 put_cpu_var(quicklist);
65 }
66
quicklist_free(int nr,void (* dtor)(void *),void * pp)67 static inline void quicklist_free(int nr, void (*dtor)(void *), void *pp)
68 {
69 __quicklist_free(nr, dtor, pp, virt_to_page(pp));
70 }
71
quicklist_free_page(int nr,void (* dtor)(void *),struct page * page)72 static inline void quicklist_free_page(int nr, void (*dtor)(void *),
73 struct page *page)
74 {
75 __quicklist_free(nr, dtor, page_address(page), page);
76 }
77
78 void quicklist_trim(int nr, void (*dtor)(void *),
79 unsigned long min_pages, unsigned long max_free);
80
81 unsigned long quicklist_total_size(void);
82
83 #else
84
quicklist_total_size(void)85 static inline unsigned long quicklist_total_size(void)
86 {
87 return 0;
88 }
89
90 #endif
91
92 #endif /* LINUX_QUICKLIST_H */
93
94