/* * arch/m68k/atari/stram.c: Functions for ST-RAM allocations * * Copyright 1994-97 Roman Hodek * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of this archive * for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_STRAM_SWAP #define MAJOR_NR Z2RAM_MAJOR #define do_z2_request do_stram_request #include #undef DEVICE_NAME #define DEVICE_NAME "stram" #endif #undef DEBUG #ifdef DEBUG #define DPRINTK(fmt,args...) printk( fmt, ##args ) #else #define DPRINTK(fmt,args...) #endif #if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC) /* abbrev for the && above... */ #define DO_PROC #include #endif /* Pre-swapping comments: * * ++roman: * * New version of ST-Ram buffer allocation. Instead of using the * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000 * (1 MB granularity!), such buffers are reserved like this: * * - If the kernel resides in ST-Ram anyway, we can take the buffer * from behind the current kernel data space the normal way * (incrementing start_mem). * * - If the kernel is in TT-Ram, stram_init() initializes start and * end of the available region. Buffers are allocated from there * and mem_init() later marks the such used pages as reserved. * Since each TT-Ram chunk is at least 4 MB in size, I hope there * won't be an overrun of the ST-Ram region by normal kernel data * space. * * For that, ST-Ram may only be allocated while kernel initialization * is going on, or exactly: before mem_init() is called. There is also * no provision now for freeing ST-Ram buffers. It seems that isn't * really needed. * */ /* * New Nov 1997: Use ST-RAM as swap space! * * In the past, there were often problems with modules that require ST-RAM * buffers. Such drivers have to use __get_dma_pages(), which unfortunately * often isn't very successful in allocating more than 1 page :-( [1] The net * result was that most of the time you couldn't insmod such modules (ataflop, * ACSI, SCSI on Falcon, Atari internal framebuffer, not to speak of acsi_slm, * which needs a 1 MB buffer... :-). * * To overcome this limitation, ST-RAM can now be turned into a very * high-speed swap space. If a request for an ST-RAM buffer comes, the kernel * now tries to unswap some pages on that swap device to make some free (and * contiguous) space. This works much better in comparison to * __get_dma_pages(), since used swap pages can be selectively freed by either * moving them to somewhere else in swap space, or by reading them back into * system memory. Ok, there operation of unswapping isn't really cheap (for * each page, one has to go through the page tables of all processes), but it * doesn't happen that often (only when allocation ST-RAM, i.e. when loading a * module that needs ST-RAM). But it at least makes it possible to load such * modules! * * It could also be that overall system performance increases a bit due to * ST-RAM swapping, since slow ST-RAM isn't used anymore for holding data or * executing code in. It's then just a (very fast, compared to disk) back * storage for not-so-often needed data. (But this effect must be compared * with the loss of total memory...) Don't know if the effect is already * visible on a TT, where the speed difference between ST- and TT-RAM isn't * that dramatic, but it should on machines where TT-RAM is really much faster * (e.g. Afterburner). * * [1]: __get_free_pages() does a fine job if you only want one page, but if * you want more (contiguous) pages, it can give you such a block only if * there's already a free one. The algorithm can't try to free buffers or swap * out something in order to make more free space, since all that page-freeing * mechanisms work "target-less", i.e. they just free something, but not in a * specific place. I.e., __get_free_pages() can't do anything to free * *adjacent* pages :-( This situation becomes even worse for DMA memory, * since the freeing algorithms are also blind to DMA capability of pages. */ /* 1998-10-20: ++andreas unswap_by_move disabled because it does not handle swapped shm pages. */ /* 2000-05-01: ++andreas Integrated with bootmem. Remove all traces of unswap_by_move. */ #ifdef CONFIG_STRAM_SWAP #define ALIGN_IF_SWAP(x) PAGE_ALIGN(x) #else #define ALIGN_IF_SWAP(x) (x) #endif /* get index of swap page at address 'addr' */ #define SWAP_NR(addr) (((addr) - swap_start) >> PAGE_SHIFT) /* get address of swap page #'nr' */ #define SWAP_ADDR(nr) (swap_start + ((nr) << PAGE_SHIFT)) /* get number of pages for 'n' bytes (already page-aligned) */ #define N_PAGES(n) ((n) >> PAGE_SHIFT) /* The following two numbers define the maximum fraction of ST-RAM in total * memory, below that the kernel would automatically use ST-RAM as swap * space. This decision can be overridden with stram_swap= */ #define MAX_STRAM_FRACTION_NOM 1 #define MAX_STRAM_FRACTION_DENOM 3 /* Start and end (virtual) of ST-RAM */ static void *stram_start, *stram_end; /* set after memory_init() executed and allocations via start_mem aren't * possible anymore */ static int mem_init_done = 0; /* set if kernel is in ST-RAM */ static int kernel_in_stram; typedef struct stram_block { struct stram_block *next; void *start; unsigned long size; unsigned flags; const char *owner; } BLOCK; /* values for flags field */ #define BLOCK_FREE 0x01 /* free structure in the BLOCKs pool */ #define BLOCK_KMALLOCED 0x02 /* structure allocated by kmalloc() */ #define BLOCK_GFP 0x08 /* block allocated with __get_dma_pages() */ #define BLOCK_INSWAP 0x10 /* block allocated in swap space */ /* list of allocated blocks */ static BLOCK *alloc_list = NULL; /* We can't always use kmalloc() to allocate BLOCK structures, since * stram_alloc() can be called rather early. So we need some pool of * statically allocated structures. 20 of them is more than enough, so in most * cases we never should need to call kmalloc(). */ #define N_STATIC_BLOCKS 20 static BLOCK static_blocks[N_STATIC_BLOCKS]; #ifdef CONFIG_STRAM_SWAP /* max. number of bytes to use for swapping * 0 = no ST-RAM swapping * -1 = do swapping (to whole ST-RAM) if it's less than MAX_STRAM_FRACTION of * total memory */ static int max_swap_size = 0; /* start and end of swapping area */ static void *swap_start, *swap_end; /* The ST-RAM's swap info structure */ static struct swap_info_struct *stram_swap_info; /* The ST-RAM's swap type */ static int stram_swap_type; /* Semaphore for get_stram_region. */ static DECLARE_MUTEX(stram_swap_sem); /* major and minor device number of the ST-RAM device; for the major, we use * the same as Amiga z2ram, which is really similar and impossible on Atari, * and for the minor a relatively odd number to avoid the user creating and * using that device. */ #define STRAM_MAJOR Z2RAM_MAJOR #define STRAM_MINOR 13 /* Some impossible pointer value */ #define MAGIC_FILE_P (struct file *)0xffffdead #ifdef DO_PROC static unsigned stat_swap_read = 0; static unsigned stat_swap_write = 0; static unsigned stat_swap_force = 0; #endif /* DO_PROC */ #endif /* CONFIG_STRAM_SWAP */ /***************************** Prototypes *****************************/ #ifdef CONFIG_STRAM_SWAP static int swap_init(void *start_mem, void *swap_data); static void *get_stram_region( unsigned long n_pages ); static void free_stram_region( unsigned long offset, unsigned long n_pages ); static int in_some_region(void *addr); static unsigned long find_free_region( unsigned long n_pages, unsigned long *total_free, unsigned long *region_free ); static void do_stram_request(request_queue_t *); static int stram_open( struct inode *inode, struct file *filp ); static int stram_release( struct inode *inode, struct file *filp ); static void reserve_region(void *start, void *end); #endif static BLOCK *add_region( void *addr, unsigned long size ); static BLOCK *find_region( void *addr ); static int remove_region( BLOCK *block ); /************************* End of Prototypes **************************/ /* ------------------------------------------------------------------------ */ /* Public Interface */ /* ------------------------------------------------------------------------ */ /* * This init function is called very early by atari/config.c * It initializes some internal variables needed for stram_alloc() */ void __init atari_stram_init(void) { int i; /* initialize static blocks */ for( i = 0; i < N_STATIC_BLOCKS; ++i ) static_blocks[i].flags = BLOCK_FREE; /* determine whether kernel code resides in ST-RAM (then ST-RAM is the * first memory block at virtual 0x0) */ stram_start = phys_to_virt(0); kernel_in_stram = (stram_start == 0); for( i = 0; i < m68k_num_memory; ++i ) { if (m68k_memory[i].addr == 0) { /* skip first 2kB or page (supervisor-only!) */ stram_end = stram_start + m68k_memory[i].size; return; } } /* Should never come here! (There is always ST-Ram!) */ panic( "atari_stram_init: no ST-RAM found!" ); } /* * This function is called from setup_arch() to reserve the pages needed for * ST-RAM management. */ void __init atari_stram_reserve_pages(void *start_mem) { #ifdef CONFIG_STRAM_SWAP /* if max_swap_size is negative (i.e. no stram_swap= option given), * determine at run time whether to use ST-RAM swapping */ if (max_swap_size < 0) /* Use swapping if ST-RAM doesn't make up more than MAX_STRAM_FRACTION * of total memory. In that case, the max. size is set to 16 MB, * because ST-RAM can never be bigger than that. * Also, never use swapping on a Hades, there's no separate ST-RAM in * that machine. */ max_swap_size = (!MACH_IS_HADES && (N_PAGES(stram_end-stram_start)*MAX_STRAM_FRACTION_DENOM <= ((unsigned long)high_memory>>PAGE_SHIFT)*MAX_STRAM_FRACTION_NOM)) ? 16*1024*1024 : 0; DPRINTK( "atari_stram_reserve_pages: max_swap_size = %d\n", max_swap_size ); #endif /* always reserve first page of ST-RAM, the first 2 kB are * supervisor-only! */ if (!kernel_in_stram) reserve_bootmem (0, PAGE_SIZE); #ifdef CONFIG_STRAM_SWAP if (max_swap_size) { void *swap_data; start_mem = (void *) PAGE_ALIGN ((unsigned long) start_mem); /* determine first page to use as swap: if the kernel is in TT-RAM, this is the first page of (usable) ST-RAM; otherwise just use the end of kernel data (= start_mem) */ swap_start = !kernel_in_stram ? stram_start + PAGE_SIZE : start_mem; /* decrement by one page, rest of kernel assumes that first swap page * is always reserved and maybe doesn't handle SWP_ENTRY == 0 * correctly */ swap_start -= PAGE_SIZE; swap_end = stram_end; if (swap_end-swap_start > max_swap_size) swap_end = swap_start + max_swap_size; DPRINTK( "atari_stram_reserve_pages: swapping enabled; " "swap=%p-%p\n", swap_start, swap_end); /* reserve some amount of memory for maintainance of * swapping itself: one page for each 2048 (PAGE_SIZE/2) * swap pages. (2 bytes for each page) */ swap_data = start_mem; start_mem += ((SWAP_NR(swap_end) + PAGE_SIZE/2 - 1) >> (PAGE_SHIFT-1)) << PAGE_SHIFT; /* correct swap_start if necessary */ if (swap_start + PAGE_SIZE == swap_data) swap_start = start_mem - PAGE_SIZE; if (!swap_init( start_mem, swap_data )) { printk( KERN_ERR "ST-RAM swap space initialization failed\n" ); max_swap_size = 0; return; } /* reserve region for swapping meta-data */ reserve_region(swap_data, start_mem); /* reserve swapping area itself */ reserve_region(swap_start + PAGE_SIZE, swap_end); /* * If the whole ST-RAM is used for swapping, there are no allocatable * dma pages left. But unfortunately, some shared parts of the kernel * (particularly the SCSI mid-level) call __get_dma_pages() * unconditionally :-( These calls then fail, and scsi.c even doesn't * check for NULL return values and just crashes. The quick fix for * this (instead of doing much clean up work in the SCSI code) is to * pretend all pages are DMA-able by setting mach_max_dma_address to * ULONG_MAX. This doesn't change any functionality so far, since * get_dma_pages() shouldn't be used on Atari anyway anymore (better * use atari_stram_alloc()), and the Atari SCSI drivers don't need DMA * memory. But unfortunately there's now no kind of warning (even not * a NULL return value) if you use get_dma_pages() nevertheless :-( * You just will get non-DMA-able memory... */ mach_max_dma_address = 0xffffffff; } #endif } void atari_stram_mem_init_hook (void) { mem_init_done = 1; } /* * This is main public interface: somehow allocate a ST-RAM block * There are three strategies: * * - If we're before mem_init(), we have to make a static allocation. The * region is taken in the kernel data area (if the kernel is in ST-RAM) or * from the start of ST-RAM (if the kernel is in TT-RAM) and added to the * rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel * address space in the latter case. * * - If mem_init() already has been called and ST-RAM swapping is enabled, * try to get the memory from the (pseudo) swap-space, either free already * or by moving some other pages out of the swap. * * - If mem_init() already has been called, and ST-RAM swapping is not * enabled, the only possibility is to try with __get_dma_pages(). This has * the disadvantage that it's very hard to get more than 1 page, and it is * likely to fail :-( * */ void *atari_stram_alloc(long size, const char *owner) { void *addr = NULL; BLOCK *block; int flags; DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner); size = ALIGN_IF_SWAP(size); DPRINTK( "atari_stram_alloc: rounded size = %08lx\n", size ); #ifdef CONFIG_STRAM_SWAP if (max_swap_size) { /* If swapping is active: make some free space in the swap "device". */ DPRINTK( "atari_stram_alloc: after mem_init, swapping ok, " "calling get_region\n" ); addr = get_stram_region( N_PAGES(size) ); flags = BLOCK_INSWAP; } else #endif if (!mem_init_done) return alloc_bootmem_low(size); else { /* After mem_init() and no swapping: can only resort to * __get_dma_pages() */ addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size)); flags = BLOCK_GFP; DPRINTK( "atari_stram_alloc: after mem_init, swapping off, " "get_pages=%p\n", addr ); } if (addr) { if (!(block = add_region( addr, size ))) { /* out of memory for BLOCK structure :-( */ DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- " "freeing again\n" ); #ifdef CONFIG_STRAM_SWAP if (flags == BLOCK_INSWAP) free_stram_region( SWAP_NR(addr), N_PAGES(size) ); else #endif free_pages((unsigned long)addr, get_order(size)); return( NULL ); } block->owner = owner; block->flags |= flags; } return( addr ); } void atari_stram_free( void *addr ) { BLOCK *block; DPRINTK( "atari_stram_free(addr=%p)\n", addr ); if (!(block = find_region( addr ))) { printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p " "from %p\n", addr, __builtin_return_address(0) ); return; } DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, " "flags=%02x\n", block, block->size, block->owner, block->flags ); #ifdef CONFIG_STRAM_SWAP if (!max_swap_size) { #endif if (block->flags & BLOCK_GFP) { DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n", get_order(block->size)); free_pages((unsigned long)addr, get_order(block->size)); } else goto fail; #ifdef CONFIG_STRAM_SWAP } else if (block->flags & BLOCK_INSWAP) { DPRINTK( "atari_stram_free: is swap-alloced\n" ); free_stram_region( SWAP_NR(block->start), N_PAGES(block->size) ); } else goto fail; #endif remove_region( block ); return; fail: printk( KERN_ERR "atari_stram_free: cannot free block at %p " "(called from %p)\n", addr, __builtin_return_address(0) ); } #ifdef CONFIG_STRAM_SWAP /* ------------------------------------------------------------------------ */ /* Main Swapping Functions */ /* ------------------------------------------------------------------------ */ /* * Initialize ST-RAM swap device * (lots copied and modified from sys_swapon() in mm/swapfile.c) */ static int __init swap_init(void *start_mem, void *swap_data) { static struct dentry fake_dentry; static struct vfsmount fake_vfsmnt; struct swap_info_struct *p; struct inode swap_inode; unsigned int type; void *addr; int i, j, k, prev; DPRINTK("swap_init(start_mem=%p, swap_data=%p)\n", start_mem, swap_data); /* need at least one page for swapping to (and this also isn't very * much... :-) */ if (swap_end - swap_start < 2*PAGE_SIZE) { printk( KERN_WARNING "stram_swap_init: swap space too small\n" ); return( 0 ); } /* find free slot in swap_info */ for( p = swap_info, type = 0; type < nr_swapfiles; type++, p++ ) if (!(p->flags & SWP_USED)) break; if (type >= MAX_SWAPFILES) { printk( KERN_WARNING "stram_swap_init: max. number of " "swap devices exhausted\n" ); return( 0 ); } if (type >= nr_swapfiles) nr_swapfiles = type+1; stram_swap_info = p; stram_swap_type = type; /* fake some dir cache entries to give us some name in /dev/swaps */ fake_dentry.d_parent = &fake_dentry; fake_dentry.d_name.name = "stram (internal)"; fake_dentry.d_name.len = 16; fake_vfsmnt.mnt_parent = &fake_vfsmnt; p->flags = SWP_USED; p->swap_file = &fake_dentry; p->swap_vfsmnt = &fake_vfsmnt; p->swap_device = 0; p->swap_map = swap_data; p->cluster_nr = 0; p->next = -1; p->prio = 0x7ff0; /* a rather high priority, but not the higest * to give the user a chance to override */ /* call stram_open() directly, avoids at least the overhead in * constructing a dummy file structure... */ p->swap_device = MKDEV( STRAM_MAJOR, STRAM_MINOR ); swap_inode.i_rdev = p->swap_device; stram_open( &swap_inode, MAGIC_FILE_P ); p->max = SWAP_NR(swap_end); /* initialize swap_map: set regions that are already allocated or belong * to kernel data space to SWAP_MAP_BAD, otherwise to free */ j = 0; /* # of free pages */ k = 0; /* # of already allocated pages (from pre-mem_init stram_alloc()) */ p->lowest_bit = 0; p->highest_bit = 0; for( i = 1, addr = SWAP_ADDR(1); i < p->max; i++, addr += PAGE_SIZE ) { if (in_some_region( addr )) { p->swap_map[i] = SWAP_MAP_BAD; ++k; } else if (kernel_in_stram && addr < start_mem ) { p->swap_map[i] = SWAP_MAP_BAD; } else { p->swap_map[i] = 0; ++j; if (!p->lowest_bit) p->lowest_bit = i; p->highest_bit = i; } } /* first page always reserved (and doesn't really belong to swap space) */ p->swap_map[0] = SWAP_MAP_BAD; /* now swapping to this device ok */ p->pages = j + k; swap_list_lock(); nr_swap_pages += j; p->flags = SWP_WRITEOK; /* insert swap space into swap_list */ prev = -1; for (i = swap_list.head; i >= 0; i = swap_info[i].next) { if (p->prio >= swap_info[i].prio) { break; } prev = i; } p->next = i; if (prev < 0) { swap_list.head = swap_list.next = p - swap_info; } else { swap_info[prev].next = p - swap_info; } swap_list_unlock(); printk( KERN_INFO "Using %dk (%d pages) of ST-RAM as swap space.\n", p->pages << 2, p->pages ); return( 1 ); } /* * The swap entry has been read in advance, and we return 1 to indicate * that the page has been used or is no longer needed. * * Always set the resulting pte to be nowrite (the same as COW pages * after one process has exited). We don't know just how many PTEs will * share this swap entry, so be cautious and let do_wp_page work out * what to do if a write is requested later. */ static inline void unswap_pte(struct vm_area_struct * vma, unsigned long address, pte_t *dir, swp_entry_t entry, struct page *page) { pte_t pte = *dir; if (pte_none(pte)) return; if (pte_present(pte)) { /* If this entry is swap-cached, then page must already hold the right address for any copies in physical memory */ if (pte_page(pte) != page) return; /* We will be removing the swap cache in a moment, so... */ set_pte(dir, pte_mkdirty(pte)); return; } if (pte_val(pte) != entry.val) return; DPRINTK("unswap_pte: replacing entry %08lx by new page %p", entry.val, page); set_pte(dir, pte_mkdirty(mk_pte(page, vma->vm_page_prot))); swap_free(entry); get_page(page); ++vma->vm_mm->rss; } static inline void unswap_pmd(struct vm_area_struct * vma, pmd_t *dir, unsigned long address, unsigned long size, unsigned long offset, swp_entry_t entry, struct page *page) { pte_t * pte; unsigned long end; if (pmd_none(*dir)) return; if (pmd_bad(*dir)) { pmd_ERROR(*dir); pmd_clear(dir); return; } pte = pte_offset(dir, address); offset += address & PMD_MASK; address &= ~PMD_MASK; end = address + size; if (end > PMD_SIZE) end = PMD_SIZE; do { unswap_pte(vma, offset+address-vma->vm_start, pte, entry, page); address += PAGE_SIZE; pte++; } while (address < end); } static inline void unswap_pgd(struct vm_area_struct * vma, pgd_t *dir, unsigned long address, unsigned long size, swp_entry_t entry, struct page *page) { pmd_t * pmd; unsigned long offset, end; if (pgd_none(*dir)) return; if (pgd_bad(*dir)) { pgd_ERROR(*dir); pgd_clear(dir); return; } pmd = pmd_offset(dir, address); offset = address & PGDIR_MASK; address &= ~PGDIR_MASK; end = address + size; if (end > PGDIR_SIZE) end = PGDIR_SIZE; do { unswap_pmd(vma, pmd, address, end - address, offset, entry, page); address = (address + PMD_SIZE) & PMD_MASK; pmd++; } while (address < end); } static void unswap_vma(struct vm_area_struct * vma, pgd_t *pgdir, swp_entry_t entry, struct page *page) { unsigned long start = vma->vm_start, end = vma->vm_end; do { unswap_pgd(vma, pgdir, start, end - start, entry, page); start = (start + PGDIR_SIZE) & PGDIR_MASK; pgdir++; } while (start < end); } static void unswap_process(struct mm_struct * mm, swp_entry_t entry, struct page *page) { struct vm_area_struct* vma; /* * Go through process' page directory. */ if (!mm) return; for (vma = mm->mmap; vma; vma = vma->vm_next) { pgd_t * pgd = pgd_offset(mm, vma->vm_start); unswap_vma(vma, pgd, entry, page); } } static int unswap_by_read(unsigned short *map, unsigned long max, unsigned long start, unsigned long n_pages) { struct task_struct *p; struct page *page; swp_entry_t entry; unsigned long i; DPRINTK( "unswapping %lu..%lu by reading in\n", start, start+n_pages-1 ); for( i = start; i < start+n_pages; ++i ) { if (map[i] == SWAP_MAP_BAD) { printk( KERN_ERR "get_stram_region: page %lu already " "reserved??\n", i ); continue; } if (map[i]) { entry = SWP_ENTRY(stram_swap_type, i); DPRINTK("unswap: map[i=%lu]=%u nr_swap=%u\n", i, map[i], nr_swap_pages); swap_device_lock(stram_swap_info); map[i]++; swap_device_unlock(stram_swap_info); /* Get a page for the entry, using the existing swap cache page if there is one. Otherwise, get a clean page and read the swap into it. */ page = read_swap_cache_async(entry); if (!page) { swap_free(entry); return -ENOMEM; } read_lock(&tasklist_lock); for_each_task(p) unswap_process(p->mm, entry, page); read_unlock(&tasklist_lock); shmem_unuse(entry, page); /* Now get rid of the extra reference to the temporary page we've been using. */ if (PageSwapCache(page)) delete_from_swap_cache(page); __free_page(page); #ifdef DO_PROC stat_swap_force++; #endif } DPRINTK( "unswap: map[i=%lu]=%u nr_swap=%u\n", i, map[i], nr_swap_pages ); swap_list_lock(); swap_device_lock(stram_swap_info); map[i] = SWAP_MAP_BAD; if (stram_swap_info->lowest_bit == i) stram_swap_info->lowest_bit++; if (stram_swap_info->highest_bit == i) stram_swap_info->highest_bit--; --nr_swap_pages; swap_device_unlock(stram_swap_info); swap_list_unlock(); } return 0; } /* * reserve a region in ST-RAM swap space for an allocation */ static void *get_stram_region( unsigned long n_pages ) { unsigned short *map = stram_swap_info->swap_map; unsigned long max = stram_swap_info->max; unsigned long start, total_free, region_free; int err; void *ret = NULL; DPRINTK( "get_stram_region(n_pages=%lu)\n", n_pages ); down(&stram_swap_sem); /* disallow writing to the swap device now */ stram_swap_info->flags = SWP_USED; /* find a region of n_pages pages in the swap space including as much free * pages as possible (and excluding any already-reserved pages). */ if (!(start = find_free_region( n_pages, &total_free, ®ion_free ))) goto end; DPRINTK( "get_stram_region: region starts at %lu, has %lu free pages\n", start, region_free ); err = unswap_by_read(map, max, start, n_pages); if (err) goto end; ret = SWAP_ADDR(start); end: /* allow using swap device again */ stram_swap_info->flags = SWP_WRITEOK; up(&stram_swap_sem); DPRINTK( "get_stram_region: returning %p\n", ret ); return( ret ); } /* * free a reserved region in ST-RAM swap space */ static void free_stram_region( unsigned long offset, unsigned long n_pages ) { unsigned short *map = stram_swap_info->swap_map; DPRINTK( "free_stram_region(offset=%lu,n_pages=%lu)\n", offset, n_pages ); if (offset < 1 || offset + n_pages > stram_swap_info->max) { printk( KERN_ERR "free_stram_region: Trying to free non-ST-RAM\n" ); return; } swap_list_lock(); swap_device_lock(stram_swap_info); /* un-reserve the freed pages */ for( ; n_pages > 0; ++offset, --n_pages ) { if (map[offset] != SWAP_MAP_BAD) printk( KERN_ERR "free_stram_region: Swap page %lu was not " "reserved\n", offset ); map[offset] = 0; } /* update swapping meta-data */ if (offset < stram_swap_info->lowest_bit) stram_swap_info->lowest_bit = offset; if (offset+n_pages-1 > stram_swap_info->highest_bit) stram_swap_info->highest_bit = offset+n_pages-1; if (stram_swap_info->prio > swap_info[swap_list.next].prio) swap_list.next = swap_list.head; nr_swap_pages += n_pages; swap_device_unlock(stram_swap_info); swap_list_unlock(); } /* ------------------------------------------------------------------------ */ /* Utility Functions for Swapping */ /* ------------------------------------------------------------------------ */ /* is addr in some of the allocated regions? */ static int in_some_region(void *addr) { BLOCK *p; for( p = alloc_list; p; p = p->next ) { if (p->start <= addr && addr < p->start + p->size) return( 1 ); } return( 0 ); } static unsigned long find_free_region(unsigned long n_pages, unsigned long *total_free, unsigned long *region_free) { unsigned short *map = stram_swap_info->swap_map; unsigned long max = stram_swap_info->max; unsigned long head, tail, max_start; long nfree, max_free; /* first scan the swap space for a suitable place for the allocation */ head = 1; max_start = 0; max_free = -1; *total_free = 0; start_over: /* increment tail until final window size reached, and count free pages */ nfree = 0; for( tail = head; tail-head < n_pages && tail < max; ++tail ) { if (map[tail] == SWAP_MAP_BAD) { head = tail+1; goto start_over; } if (!map[tail]) { ++nfree; ++*total_free; } } if (tail-head < n_pages) goto out; if (nfree > max_free) { max_start = head; max_free = nfree; if (max_free >= n_pages) /* don't need more free pages... :-) */ goto out; } /* now shift the window and look for the area where as much pages as * possible are free */ while( tail < max ) { nfree -= (map[head++] == 0); if (map[tail] == SWAP_MAP_BAD) { head = tail+1; goto start_over; } if (!map[tail]) { ++nfree; ++*total_free; } ++tail; if (nfree > max_free) { max_start = head; max_free = nfree; if (max_free >= n_pages) /* don't need more free pages... :-) */ goto out; } } out: if (max_free < 0) { printk( KERN_NOTICE "get_stram_region: ST-RAM too full or fragmented " "-- can't allocate %lu pages\n", n_pages ); return( 0 ); } *region_free = max_free; return( max_start ); } #ifdef CONFIG_STRAM_SWAP /* setup parameters from command line */ void __init stram_swap_setup(char *str) { int ints[3]; get_options(str, ARRAY_SIZE(ints), ints); if (ints[0] >= 1) { if (ints[1] == 1) { /* always use ST-RAM as swap */ max_swap_size = -1; if (ints[0] == 2) { max_swap_size = ((ints[2] < 0 ? 0 : ints[2]) * 1024) & PAGE_MASK; } } else if (ints[1] == 0) { /* never use ST-RAM as swap */ max_swap_size = 0; } else { printk( KERN_WARNING "stram_swap=%d - invalid value\n", ints[1] ); } } } #endif /* CONFIG_STRAM_SWAP */ /* ------------------------------------------------------------------------ */ /* ST-RAM device */ /* ------------------------------------------------------------------------ */ static int stram_blocksizes[14] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4096 }; static int stram_sizes[14] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; static int refcnt = 0; static void do_stram_request(request_queue_t *q) { void *start; unsigned long len; while (1) { INIT_REQUEST; start = swap_start + (CURRENT->sector << 9); len = CURRENT->current_nr_sectors << 9; if ((start + len) > swap_end) { printk( KERN_ERR "stram: bad access beyond end of device: " "block=%ld, count=%ld\n", CURRENT->sector, CURRENT->current_nr_sectors ); end_request( 0 ); continue; } if (CURRENT->cmd == READ) { memcpy(CURRENT->buffer, start, len); #ifdef DO_PROC stat_swap_read += N_PAGES(len); #endif } else { memcpy(start, CURRENT->buffer, len); #ifdef DO_PROC stat_swap_write += N_PAGES(len); #endif } end_request( 1 ); } } static int stram_open( struct inode *inode, struct file *filp ) { if (filp != MAGIC_FILE_P) { printk( KERN_NOTICE "Only kernel can open ST-RAM device\n" ); return( -EPERM ); } if (MINOR(inode->i_rdev) != STRAM_MINOR) return( -ENXIO ); if (refcnt) return( -EBUSY ); ++refcnt; return( 0 ); } static int stram_release( struct inode *inode, struct file *filp ) { if (filp != MAGIC_FILE_P) { printk( KERN_NOTICE "Only kernel can close ST-RAM device\n" ); return( -EPERM ); } if (refcnt > 0) --refcnt; return( 0 ); } static struct block_device_operations stram_fops = { open: stram_open, release: stram_release, }; int __init stram_device_init(void) { if (!MACH_IS_ATARI) /* no point in initializing this, I hope */ return( -ENXIO ); if (!max_swap_size) /* swapping not enabled */ return( -ENXIO ); if (register_blkdev( STRAM_MAJOR, "stram", &stram_fops)) { printk( KERN_ERR "stram: Unable to get major %d\n", STRAM_MAJOR ); return( -ENXIO ); } blk_init_queue(BLK_DEFAULT_QUEUE(STRAM_MAJOR), do_stram_request); blksize_size[STRAM_MAJOR] = stram_blocksizes; stram_sizes[STRAM_MINOR] = (swap_end - swap_start)/1024; blk_size[STRAM_MAJOR] = stram_sizes; register_disk(NULL, MKDEV(STRAM_MAJOR, STRAM_MINOR), 1, &stram_fops, (swap_end-swap_start)>>9); return( 0 ); } /* ------------------------------------------------------------------------ */ /* Misc Utility Functions */ /* ------------------------------------------------------------------------ */ /* reserve a range of pages */ static void reserve_region(void *start, void *end) { reserve_bootmem (virt_to_phys(start), end - start); } #endif /* CONFIG_STRAM_SWAP */ /* ------------------------------------------------------------------------ */ /* Region Management */ /* ------------------------------------------------------------------------ */ /* insert a region into the alloced list (sorted) */ static BLOCK *add_region( void *addr, unsigned long size ) { BLOCK **p, *n = NULL; int i; for( i = 0; i < N_STATIC_BLOCKS; ++i ) { if (static_blocks[i].flags & BLOCK_FREE) { n = &static_blocks[i]; n->flags = 0; break; } } if (!n && mem_init_done) { /* if statics block pool exhausted and we can call kmalloc() already * (after mem_init()), try that */ n = kmalloc( sizeof(BLOCK), GFP_KERNEL ); if (n) n->flags = BLOCK_KMALLOCED; } if (!n) { printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" ); return( NULL ); } n->start = addr; n->size = size; for( p = &alloc_list; *p; p = &((*p)->next) ) if ((*p)->start > addr) break; n->next = *p; *p = n; return( n ); } /* find a region (by start addr) in the alloced list */ static BLOCK *find_region( void *addr ) { BLOCK *p; for( p = alloc_list; p; p = p->next ) { if (p->start == addr) return( p ); if (p->start > addr) break; } return( NULL ); } /* remove a block from the alloced list */ static int remove_region( BLOCK *block ) { BLOCK **p; for( p = &alloc_list; *p; p = &((*p)->next) ) if (*p == block) break; if (!*p) return( 0 ); *p = block->next; if (block->flags & BLOCK_KMALLOCED) kfree( block ); else block->flags |= BLOCK_FREE; return( 1 ); } /* ------------------------------------------------------------------------ */ /* /proc statistics file stuff */ /* ------------------------------------------------------------------------ */ #ifdef DO_PROC #define PRINT_PROC(fmt,args...) len += sprintf( buf+len, fmt, ##args ) int get_stram_list( char *buf ) { int len = 0; BLOCK *p; #ifdef CONFIG_STRAM_SWAP int i; unsigned short *map = stram_swap_info->swap_map; unsigned long max = stram_swap_info->max; unsigned free = 0, used = 0, rsvd = 0; #endif #ifdef CONFIG_STRAM_SWAP if (max_swap_size) { for( i = 1; i < max; ++i ) { if (!map[i]) ++free; else if (map[i] == SWAP_MAP_BAD) ++rsvd; else ++used; } PRINT_PROC( "Total ST-RAM: %8u kB\n" "Total ST-RAM swap: %8lu kB\n" "Free swap: %8u kB\n" "Used swap: %8u kB\n" "Allocated swap: %8u kB\n" "Swap Reads: %8u\n" "Swap Writes: %8u\n" "Swap Forced Reads: %8u\n", (stram_end - stram_start) >> 10, (max-1) << (PAGE_SHIFT-10), free << (PAGE_SHIFT-10), used << (PAGE_SHIFT-10), rsvd << (PAGE_SHIFT-10), stat_swap_read, stat_swap_write, stat_swap_force ); } else { #endif PRINT_PROC( "ST-RAM swapping disabled\n" ); PRINT_PROC("Total ST-RAM: %8u kB\n", (stram_end - stram_start) >> 10); #ifdef CONFIG_STRAM_SWAP } #endif PRINT_PROC( "Allocated regions:\n" ); for( p = alloc_list; p; p = p->next ) { if (len + 50 >= PAGE_SIZE) break; PRINT_PROC("0x%08lx-0x%08lx: %s (", virt_to_phys(p->start), virt_to_phys(p->start+p->size-1), p->owner); if (p->flags & BLOCK_GFP) PRINT_PROC( "page-alloced)\n" ); else if (p->flags & BLOCK_INSWAP) PRINT_PROC( "in swap)\n" ); else PRINT_PROC( "??)\n" ); } return( len ); } #endif /* * Local variables: * c-indent-level: 4 * tab-width: 4 * End: */