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mm/swapfile.c
43.1 KB
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/* * linux/mm/swapfile.c * * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * Swap reorganised 29.12.95, Stephen Tweedie */ |
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#include <linux/mm.h> #include <linux/hugetlb.h> #include <linux/mman.h> #include <linux/slab.h> #include <linux/kernel_stat.h> #include <linux/swap.h> #include <linux/vmalloc.h> #include <linux/pagemap.h> #include <linux/namei.h> #include <linux/shm.h> #include <linux/blkdev.h> #include <linux/writeback.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/init.h> #include <linux/module.h> #include <linux/rmap.h> #include <linux/security.h> #include <linux/backing-dev.h> |
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#include <linux/mutex.h> |
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#include <linux/capability.h> |
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#include <linux/syscalls.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> #include <linux/swapops.h> |
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DEFINE_SPINLOCK(swap_lock); |
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unsigned int nr_swapfiles; long total_swap_pages; static int swap_overflow; |
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static const char Bad_file[] = "Bad swap file entry "; static const char Unused_file[] = "Unused swap file entry "; static const char Bad_offset[] = "Bad swap offset entry "; static const char Unused_offset[] = "Unused swap offset entry "; struct swap_list_t swap_list = {-1, -1}; |
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static struct swap_info_struct swap_info[MAX_SWAPFILES]; |
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|
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static DEFINE_MUTEX(swapon_mutex); |
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/* * We need this because the bdev->unplug_fn can sleep and we cannot |
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* hold swap_lock while calling the unplug_fn. And swap_lock |
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* cannot be turned into a mutex. |
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*/ static DECLARE_RWSEM(swap_unplug_sem); |
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void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page) { swp_entry_t entry; down_read(&swap_unplug_sem); |
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entry.val = page_private(page); |
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if (PageSwapCache(page)) { struct block_device *bdev = swap_info[swp_type(entry)].bdev; struct backing_dev_info *bdi; /* * If the page is removed from swapcache from under us (with a * racy try_to_unuse/swapoff) we need an additional reference |
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* count to avoid reading garbage from page_private(page) above. * If the WARN_ON triggers during a swapoff it maybe the race |
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* condition and it's harmless. However if it triggers without * swapoff it signals a problem. */ WARN_ON(page_count(page) <= 1); bdi = bdev->bd_inode->i_mapping->backing_dev_info; |
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blk_run_backing_dev(bdi, page); |
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} up_read(&swap_unplug_sem); } |
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#define SWAPFILE_CLUSTER 256 #define LATENCY_LIMIT 256 |
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static inline unsigned long scan_swap_map(struct swap_info_struct *si) |
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{ |
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unsigned long offset, last_in_cluster; |
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int latency_ration = LATENCY_LIMIT; |
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|
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/* |
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* We try to cluster swap pages by allocating them sequentially * in swap. Once we've allocated SWAPFILE_CLUSTER pages this * way, however, we resort to first-free allocation, starting * a new cluster. This prevents us from scattering swap pages * all over the entire swap partition, so that we reduce * overall disk seek times between swap pages. -- sct * But we do now try to find an empty cluster. -Andrea */ |
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si->flags += SWP_SCANNING; |
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if (unlikely(!si->cluster_nr)) { si->cluster_nr = SWAPFILE_CLUSTER - 1; if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) goto lowest; |
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spin_unlock(&swap_lock); |
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offset = si->lowest_bit; last_in_cluster = offset + SWAPFILE_CLUSTER - 1; /* Locate the first empty (unaligned) cluster */ for (; last_in_cluster <= si->highest_bit; offset++) { |
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if (si->swap_map[offset]) |
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last_in_cluster = offset + SWAPFILE_CLUSTER; else if (offset == last_in_cluster) { |
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spin_lock(&swap_lock); |
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si->cluster_next = offset-SWAPFILE_CLUSTER+1; |
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goto cluster; |
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} |
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if (unlikely(--latency_ration < 0)) { cond_resched(); latency_ration = LATENCY_LIMIT; } |
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} |
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spin_lock(&swap_lock); |
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goto lowest; |
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} |
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si->cluster_nr--; cluster: offset = si->cluster_next; if (offset > si->highest_bit) lowest: offset = si->lowest_bit; |
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checks: if (!(si->flags & SWP_WRITEOK)) goto no_page; |
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if (!si->highest_bit) goto no_page; if (!si->swap_map[offset]) { |
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if (offset == si->lowest_bit) |
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si->lowest_bit++; if (offset == si->highest_bit) si->highest_bit--; |
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si->inuse_pages++; if (si->inuse_pages == si->pages) { |
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si->lowest_bit = si->max; si->highest_bit = 0; } si->swap_map[offset] = 1; |
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si->cluster_next = offset + 1; |
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si->flags -= SWP_SCANNING; |
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return offset; } |
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|
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spin_unlock(&swap_lock); |
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while (++offset <= si->highest_bit) { |
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if (!si->swap_map[offset]) { |
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spin_lock(&swap_lock); |
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goto checks; } |
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if (unlikely(--latency_ration < 0)) { cond_resched(); latency_ration = LATENCY_LIMIT; } |
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} |
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spin_lock(&swap_lock); |
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goto lowest; no_page: |
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si->flags -= SWP_SCANNING; |
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return 0; } swp_entry_t get_swap_page(void) { |
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struct swap_info_struct *si; pgoff_t offset; int type, next; int wrapped = 0; |
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|
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spin_lock(&swap_lock); |
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if (nr_swap_pages <= 0) |
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goto noswap; nr_swap_pages--; for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) { si = swap_info + type; next = si->next; if (next < 0 || (!wrapped && si->prio != swap_info[next].prio)) { next = swap_list.head; wrapped++; |
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} |
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if (!si->highest_bit) continue; if (!(si->flags & SWP_WRITEOK)) continue; swap_list.next = next; |
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offset = scan_swap_map(si); |
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if (offset) { spin_unlock(&swap_lock); |
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return swp_entry(type, offset); |
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} |
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next = swap_list.next; |
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} |
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nr_swap_pages++; noswap: |
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spin_unlock(&swap_lock); |
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return (swp_entry_t) {0}; |
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} |
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swp_entry_t get_swap_page_of_type(int type) { struct swap_info_struct *si; pgoff_t offset; spin_lock(&swap_lock); si = swap_info + type; if (si->flags & SWP_WRITEOK) { nr_swap_pages--; offset = scan_swap_map(si); if (offset) { spin_unlock(&swap_lock); return swp_entry(type, offset); } nr_swap_pages++; } spin_unlock(&swap_lock); return (swp_entry_t) {0}; } |
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static struct swap_info_struct * swap_info_get(swp_entry_t entry) { struct swap_info_struct * p; unsigned long offset, type; if (!entry.val) goto out; type = swp_type(entry); if (type >= nr_swapfiles) goto bad_nofile; p = & swap_info[type]; if (!(p->flags & SWP_USED)) goto bad_device; offset = swp_offset(entry); if (offset >= p->max) goto bad_offset; if (!p->swap_map[offset]) goto bad_free; |
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spin_lock(&swap_lock); |
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return p; bad_free: printk(KERN_ERR "swap_free: %s%08lx ", Unused_offset, entry.val); goto out; bad_offset: printk(KERN_ERR "swap_free: %s%08lx ", Bad_offset, entry.val); goto out; bad_device: printk(KERN_ERR "swap_free: %s%08lx ", Unused_file, entry.val); goto out; bad_nofile: printk(KERN_ERR "swap_free: %s%08lx ", Bad_file, entry.val); out: return NULL; } |
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static int swap_entry_free(struct swap_info_struct *p, unsigned long offset) { int count = p->swap_map[offset]; if (count < SWAP_MAP_MAX) { count--; p->swap_map[offset] = count; if (!count) { if (offset < p->lowest_bit) p->lowest_bit = offset; if (offset > p->highest_bit) p->highest_bit = offset; |
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if (p->prio > swap_info[swap_list.next].prio) swap_list.next = p - swap_info; |
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nr_swap_pages++; p->inuse_pages--; } } return count; } /* * Caller has made sure that the swapdevice corresponding to entry * is still around or has not been recycled. */ void swap_free(swp_entry_t entry) { struct swap_info_struct * p; p = swap_info_get(entry); if (p) { swap_entry_free(p, swp_offset(entry)); |
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spin_unlock(&swap_lock); |
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} } /* |
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* How many references to page are currently swapped out? |
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*/ |
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static inline int page_swapcount(struct page *page) |
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{ |
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int count = 0; struct swap_info_struct *p; |
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swp_entry_t entry; |
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entry.val = page_private(page); |
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p = swap_info_get(entry); if (p) { |
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/* Subtract the 1 for the swap cache itself */ count = p->swap_map[swp_offset(entry)] - 1; |
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spin_unlock(&swap_lock); |
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} |
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return count; |
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} /* * We can use this swap cache entry directly * if there are no other references to it. |
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*/ int can_share_swap_page(struct page *page) { |
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int count; BUG_ON(!PageLocked(page)); count = page_mapcount(page); if (count <= 1 && PageSwapCache(page)) count += page_swapcount(page); return count == 1; |
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} /* * Work out if there are any other processes sharing this * swap cache page. Free it if you can. Return success. */ int remove_exclusive_swap_page(struct page *page) { int retval; struct swap_info_struct * p; swp_entry_t entry; BUG_ON(PagePrivate(page)); BUG_ON(!PageLocked(page)); if (!PageSwapCache(page)) return 0; if (PageWriteback(page)) return 0; if (page_count(page) != 2) /* 2: us + cache */ return 0; |
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entry.val = page_private(page); |
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p = swap_info_get(entry); if (!p) return 0; /* Is the only swap cache user the cache itself? */ retval = 0; if (p->swap_map[swp_offset(entry)] == 1) { /* Recheck the page count with the swapcache lock held.. */ write_lock_irq(&swapper_space.tree_lock); if ((page_count(page) == 2) && !PageWriteback(page)) { __delete_from_swap_cache(page); SetPageDirty(page); retval = 1; } write_unlock_irq(&swapper_space.tree_lock); } |
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spin_unlock(&swap_lock); |
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if (retval) { swap_free(entry); page_cache_release(page); } return retval; } /* * Free the swap entry like above, but also try to * free the page cache entry if it is the last user. */ void free_swap_and_cache(swp_entry_t entry) { struct swap_info_struct * p; struct page *page = NULL; |
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if (is_migration_entry(entry)) return; |
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p = swap_info_get(entry); if (p) { |
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if (swap_entry_free(p, swp_offset(entry)) == 1) { page = find_get_page(&swapper_space, entry.val); if (page && unlikely(TestSetPageLocked(page))) { page_cache_release(page); page = NULL; } } |
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spin_unlock(&swap_lock); |
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} if (page) { int one_user; BUG_ON(PagePrivate(page)); |
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one_user = (page_count(page) == 2); /* Only cache user (+us), or swap space full? Free it! */ |
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/* Also recheck PageSwapCache after page is locked (above) */ if (PageSwapCache(page) && !PageWriteback(page) && (one_user || vm_swap_full())) { |
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delete_from_swap_cache(page); SetPageDirty(page); } unlock_page(page); page_cache_release(page); } } |
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#ifdef CONFIG_SOFTWARE_SUSPEND /* * Find the swap type that corresponds to given device (if any) * * This is needed for software suspend and is done in such a way that inode * aliasing is allowed. */ int swap_type_of(dev_t device) { int i; |
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spin_lock(&swap_lock); for (i = 0; i < nr_swapfiles; i++) { struct inode *inode; if (!(swap_info[i].flags & SWP_WRITEOK)) continue; |
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|
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if (!device) { spin_unlock(&swap_lock); return i; } |
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inode = swap_info[i].swap_file->f_dentry->d_inode; |
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if (S_ISBLK(inode->i_mode) && device == MKDEV(imajor(inode), iminor(inode))) { spin_unlock(&swap_lock); return i; } } spin_unlock(&swap_lock); return -ENODEV; } /* * Return either the total number of swap pages of given type, or the number * of free pages of that type (depending on @free) * * This is needed for software suspend */ unsigned int count_swap_pages(int type, int free) { unsigned int n = 0; if (type < nr_swapfiles) { spin_lock(&swap_lock); if (swap_info[type].flags & SWP_WRITEOK) { n = swap_info[type].pages; if (free) n -= swap_info[type].inuse_pages; } spin_unlock(&swap_lock); } return n; } #endif |
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/* |
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* No need to decide whether this PTE shares the swap entry with others, * just let do_wp_page work it out if a write is requested later - to * force COW, vm_page_prot omits write permission from any private vma. |
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*/ static void unuse_pte(struct vm_area_struct *vma, pte_t *pte, unsigned long addr, swp_entry_t entry, struct page *page) { |
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inc_mm_counter(vma->vm_mm, anon_rss); |
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get_page(page); set_pte_at(vma->vm_mm, addr, pte, pte_mkold(mk_pte(page, vma->vm_page_prot))); page_add_anon_rmap(page, vma, addr); swap_free(entry); /* * Move the page to the active list so it is not * immediately swapped out again after swapon. */ activate_page(page); } static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, swp_entry_t entry, struct page *page) { |
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pte_t swp_pte = swp_entry_to_pte(entry); |
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pte_t *pte; spinlock_t *ptl; int found = 0; |
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|
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pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
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do { /* * swapoff spends a _lot_ of time in this loop! * Test inline before going to call unuse_pte. */ if (unlikely(pte_same(*pte, swp_pte))) { |
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unuse_pte(vma, pte++, addr, entry, page); found = 1; break; |
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} } while (pte++, addr += PAGE_SIZE, addr != end); |
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pte_unmap_unlock(pte - 1, ptl); return found; |
1da177e4c Linux-2.6.12-rc2 |
514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 |
} static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, unsigned long addr, unsigned long end, swp_entry_t entry, struct page *page) { pmd_t *pmd; unsigned long next; pmd = pmd_offset(pud, addr); do { next = pmd_addr_end(addr, end); if (pmd_none_or_clear_bad(pmd)) continue; if (unuse_pte_range(vma, pmd, addr, next, entry, page)) return 1; } while (pmd++, addr = next, addr != end); return 0; } static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr, unsigned long end, swp_entry_t entry, struct page *page) { pud_t *pud; unsigned long next; pud = pud_offset(pgd, addr); do { next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; if (unuse_pmd_range(vma, pud, addr, next, entry, page)) return 1; } while (pud++, addr = next, addr != end); return 0; } static int unuse_vma(struct vm_area_struct *vma, swp_entry_t entry, struct page *page) { pgd_t *pgd; unsigned long addr, end, next; if (page->mapping) { addr = page_address_in_vma(page, vma); if (addr == -EFAULT) return 0; else end = addr + PAGE_SIZE; } else { addr = vma->vm_start; end = vma->vm_end; } pgd = pgd_offset(vma->vm_mm, addr); do { next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; if (unuse_pud_range(vma, pgd, addr, next, entry, page)) return 1; } while (pgd++, addr = next, addr != end); return 0; } static int unuse_mm(struct mm_struct *mm, swp_entry_t entry, struct page *page) { struct vm_area_struct *vma; if (!down_read_trylock(&mm->mmap_sem)) { /* |
c475a8ab6 [PATCH] can_share... |
587 588 |
* Activate page so shrink_cache is unlikely to unmap its * ptes while lock is dropped, so swapoff can make progress. |
1da177e4c Linux-2.6.12-rc2 |
589 |
*/ |
c475a8ab6 [PATCH] can_share... |
590 |
activate_page(page); |
1da177e4c Linux-2.6.12-rc2 |
591 592 593 594 |
unlock_page(page); down_read(&mm->mmap_sem); lock_page(page); } |
1da177e4c Linux-2.6.12-rc2 |
595 596 597 598 |
for (vma = mm->mmap; vma; vma = vma->vm_next) { if (vma->anon_vma && unuse_vma(vma, entry, page)) break; } |
1da177e4c Linux-2.6.12-rc2 |
599 600 601 602 603 604 605 606 607 608 609 610 |
up_read(&mm->mmap_sem); /* * Currently unuse_mm cannot fail, but leave error handling * at call sites for now, since we change it from time to time. */ return 0; } /* * Scan swap_map from current position to next entry still in use. * Recycle to start on reaching the end, returning 0 when empty. */ |
6eb396dc4 [PATCH] swap: swa... |
611 612 |
static unsigned int find_next_to_unuse(struct swap_info_struct *si, unsigned int prev) |
1da177e4c Linux-2.6.12-rc2 |
613 |
{ |
6eb396dc4 [PATCH] swap: swa... |
614 615 |
unsigned int max = si->max; unsigned int i = prev; |
1da177e4c Linux-2.6.12-rc2 |
616 617 618 |
int count; /* |
5d337b919 [PATCH] swap: swa... |
619 |
* No need for swap_lock here: we're just looking |
1da177e4c Linux-2.6.12-rc2 |
620 621 |
* for whether an entry is in use, not modifying it; false * hits are okay, and sys_swapoff() has already prevented new |
5d337b919 [PATCH] swap: swa... |
622 |
* allocations from this area (while holding swap_lock). |
1da177e4c Linux-2.6.12-rc2 |
623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 |
*/ for (;;) { if (++i >= max) { if (!prev) { i = 0; break; } /* * No entries in use at top of swap_map, * loop back to start and recheck there. */ max = prev + 1; prev = 0; i = 1; } count = si->swap_map[i]; if (count && count != SWAP_MAP_BAD) break; } return i; } /* * We completely avoid races by reading each swap page in advance, * and then search for the process using it. All the necessary * page table adjustments can then be made atomically. */ static int try_to_unuse(unsigned int type) { struct swap_info_struct * si = &swap_info[type]; struct mm_struct *start_mm; unsigned short *swap_map; unsigned short swcount; struct page *page; swp_entry_t entry; |
6eb396dc4 [PATCH] swap: swa... |
658 |
unsigned int i = 0; |
1da177e4c Linux-2.6.12-rc2 |
659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 |
int retval = 0; int reset_overflow = 0; int shmem; /* * When searching mms for an entry, a good strategy is to * start at the first mm we freed the previous entry from * (though actually we don't notice whether we or coincidence * freed the entry). Initialize this start_mm with a hold. * * A simpler strategy would be to start at the last mm we * freed the previous entry from; but that would take less * advantage of mmlist ordering, which clusters forked mms * together, child after parent. If we race with dup_mmap(), we * prefer to resolve parent before child, lest we miss entries * duplicated after we scanned child: using last mm would invert * that. Though it's only a serious concern when an overflowed * swap count is reset from SWAP_MAP_MAX, preventing a rescan. */ start_mm = &init_mm; atomic_inc(&init_mm.mm_users); /* * Keep on scanning until all entries have gone. Usually, * one pass through swap_map is enough, but not necessarily: * there are races when an instance of an entry might be missed. */ while ((i = find_next_to_unuse(si, i)) != 0) { if (signal_pending(current)) { retval = -EINTR; break; } /* * 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. */ swap_map = &si->swap_map[i]; entry = swp_entry(type, i); page = read_swap_cache_async(entry, NULL, 0); if (!page) { /* * Either swap_duplicate() failed because entry * has been freed independently, and will not be * reused since sys_swapoff() already disabled * allocation from here, or alloc_page() failed. */ if (!*swap_map) continue; retval = -ENOMEM; break; } /* * Don't hold on to start_mm if it looks like exiting. */ if (atomic_read(&start_mm->mm_users) == 1) { mmput(start_mm); start_mm = &init_mm; atomic_inc(&init_mm.mm_users); } /* * Wait for and lock page. When do_swap_page races with * try_to_unuse, do_swap_page can handle the fault much * faster than try_to_unuse can locate the entry. This * apparently redundant "wait_on_page_locked" lets try_to_unuse * defer to do_swap_page in such a case - in some tests, * do_swap_page and try_to_unuse repeatedly compete. */ wait_on_page_locked(page); wait_on_page_writeback(page); lock_page(page); wait_on_page_writeback(page); /* * Remove all references to entry. * Whenever we reach init_mm, there's no address space * to search, but use it as a reminder to search shmem. */ shmem = 0; swcount = *swap_map; if (swcount > 1) { if (start_mm == &init_mm) shmem = shmem_unuse(entry, page); else retval = unuse_mm(start_mm, entry, page); } if (*swap_map > 1) { int set_start_mm = (*swap_map >= swcount); struct list_head *p = &start_mm->mmlist; struct mm_struct *new_start_mm = start_mm; struct mm_struct *prev_mm = start_mm; struct mm_struct *mm; atomic_inc(&new_start_mm->mm_users); atomic_inc(&prev_mm->mm_users); spin_lock(&mmlist_lock); while (*swap_map > 1 && !retval && (p = p->next) != &start_mm->mmlist) { mm = list_entry(p, struct mm_struct, mmlist); |
70af7c5c6 [PATCH] swapoff: ... |
761 |
if (!atomic_inc_not_zero(&mm->mm_users)) |
1da177e4c Linux-2.6.12-rc2 |
762 |
continue; |
1da177e4c Linux-2.6.12-rc2 |
763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 |
spin_unlock(&mmlist_lock); mmput(prev_mm); prev_mm = mm; cond_resched(); swcount = *swap_map; if (swcount <= 1) ; else if (mm == &init_mm) { set_start_mm = 1; shmem = shmem_unuse(entry, page); } else retval = unuse_mm(mm, entry, page); if (set_start_mm && *swap_map < swcount) { mmput(new_start_mm); atomic_inc(&mm->mm_users); new_start_mm = mm; set_start_mm = 0; } spin_lock(&mmlist_lock); } spin_unlock(&mmlist_lock); mmput(prev_mm); mmput(start_mm); start_mm = new_start_mm; } if (retval) { unlock_page(page); page_cache_release(page); break; } /* * How could swap count reach 0x7fff when the maximum * pid is 0x7fff, and there's no way to repeat a swap * page within an mm (except in shmem, where it's the * shared object which takes the reference count)? * We believe SWAP_MAP_MAX cannot occur in Linux 2.4. * * If that's wrong, then we should worry more about * exit_mmap() and do_munmap() cases described above: * we might be resetting SWAP_MAP_MAX too early here. * We know "Undead"s can happen, they're okay, so don't * report them; but do report if we reset SWAP_MAP_MAX. */ if (*swap_map == SWAP_MAP_MAX) { |
5d337b919 [PATCH] swap: swa... |
810 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
811 |
*swap_map = 1; |
5d337b919 [PATCH] swap: swa... |
812 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 |
reset_overflow = 1; } /* * If a reference remains (rare), we would like to leave * the page in the swap cache; but try_to_unmap could * then re-duplicate the entry once we drop page lock, * so we might loop indefinitely; also, that page could * not be swapped out to other storage meanwhile. So: * delete from cache even if there's another reference, * after ensuring that the data has been saved to disk - * since if the reference remains (rarer), it will be * read from disk into another page. Splitting into two * pages would be incorrect if swap supported "shared * private" pages, but they are handled by tmpfs files. * * Note shmem_unuse already deleted a swappage from * the swap cache, unless the move to filepage failed: * in which case it left swappage in cache, lowered its * swap count to pass quickly through the loops above, * and now we must reincrement count to try again later. */ if ((*swap_map > 1) && PageDirty(page) && PageSwapCache(page)) { struct writeback_control wbc = { .sync_mode = WB_SYNC_NONE, }; swap_writepage(page, &wbc); lock_page(page); wait_on_page_writeback(page); } if (PageSwapCache(page)) { if (shmem) swap_duplicate(entry); else delete_from_swap_cache(page); } /* * So we could skip searching mms once swap count went * to 1, we did not mark any present ptes as dirty: must * mark page dirty so shrink_list will preserve it. */ SetPageDirty(page); unlock_page(page); page_cache_release(page); /* * Make sure that we aren't completely killing * interactive performance. */ cond_resched(); } mmput(start_mm); if (reset_overflow) { printk(KERN_WARNING "swapoff: cleared swap entry overflow "); swap_overflow = 0; } return retval; } /* |
5d337b919 [PATCH] swap: swa... |
877 878 879 |
* After a successful try_to_unuse, if no swap is now in use, we know * we can empty the mmlist. swap_lock must be held on entry and exit. * Note that mmlist_lock nests inside swap_lock, and an mm must be |
1da177e4c Linux-2.6.12-rc2 |
880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 |
* added to the mmlist just after page_duplicate - before would be racy. */ static void drain_mmlist(void) { struct list_head *p, *next; unsigned int i; for (i = 0; i < nr_swapfiles; i++) if (swap_info[i].inuse_pages) return; spin_lock(&mmlist_lock); list_for_each_safe(p, next, &init_mm.mmlist) list_del_init(p); spin_unlock(&mmlist_lock); } /* * Use this swapdev's extent info to locate the (PAGE_SIZE) block which * corresponds to page offset `offset'. */ sector_t map_swap_page(struct swap_info_struct *sis, pgoff_t offset) { struct swap_extent *se = sis->curr_swap_extent; struct swap_extent *start_se = se; for ( ; ; ) { struct list_head *lh; if (se->start_page <= offset && offset < (se->start_page + se->nr_pages)) { return se->start_block + (offset - se->start_page); } |
11d31886d [PATCH] swap: swa... |
912 |
lh = se->list.next; |
1da177e4c Linux-2.6.12-rc2 |
913 |
if (lh == &sis->extent_list) |
11d31886d [PATCH] swap: swa... |
914 |
lh = lh->next; |
1da177e4c Linux-2.6.12-rc2 |
915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 |
se = list_entry(lh, struct swap_extent, list); sis->curr_swap_extent = se; BUG_ON(se == start_se); /* It *must* be present */ } } /* * Free all of a swapdev's extent information */ static void destroy_swap_extents(struct swap_info_struct *sis) { while (!list_empty(&sis->extent_list)) { struct swap_extent *se; se = list_entry(sis->extent_list.next, struct swap_extent, list); list_del(&se->list); kfree(se); } |
1da177e4c Linux-2.6.12-rc2 |
934 935 936 937 |
} /* * Add a block range (and the corresponding page range) into this swapdev's |
11d31886d [PATCH] swap: swa... |
938 |
* extent list. The extent list is kept sorted in page order. |
1da177e4c Linux-2.6.12-rc2 |
939 |
* |
11d31886d [PATCH] swap: swa... |
940 |
* This function rather assumes that it is called in ascending page order. |
1da177e4c Linux-2.6.12-rc2 |
941 942 943 944 945 946 947 948 |
*/ static int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, unsigned long nr_pages, sector_t start_block) { struct swap_extent *se; struct swap_extent *new_se; struct list_head *lh; |
11d31886d [PATCH] swap: swa... |
949 950 |
lh = sis->extent_list.prev; /* The highest page extent */ if (lh != &sis->extent_list) { |
1da177e4c Linux-2.6.12-rc2 |
951 |
se = list_entry(lh, struct swap_extent, list); |
11d31886d [PATCH] swap: swa... |
952 953 |
BUG_ON(se->start_page + se->nr_pages != start_page); if (se->start_block + se->nr_pages == start_block) { |
1da177e4c Linux-2.6.12-rc2 |
954 955 956 957 |
/* Merge it */ se->nr_pages += nr_pages; return 0; } |
1da177e4c Linux-2.6.12-rc2 |
958 959 960 961 962 963 964 965 966 967 968 |
} /* * No merge. Insert a new extent, preserving ordering. */ new_se = kmalloc(sizeof(*se), GFP_KERNEL); if (new_se == NULL) return -ENOMEM; new_se->start_page = start_page; new_se->nr_pages = nr_pages; new_se->start_block = start_block; |
11d31886d [PATCH] swap: swa... |
969 |
list_add_tail(&new_se->list, &sis->extent_list); |
53092a740 [PATCH] swap: sho... |
970 |
return 1; |
1da177e4c Linux-2.6.12-rc2 |
971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 |
} /* * A `swap extent' is a simple thing which maps a contiguous range of pages * onto a contiguous range of disk blocks. An ordered list of swap extents * is built at swapon time and is then used at swap_writepage/swap_readpage * time for locating where on disk a page belongs. * * If the swapfile is an S_ISBLK block device, a single extent is installed. * This is done so that the main operating code can treat S_ISBLK and S_ISREG * swap files identically. * * Whether the swapdev is an S_ISREG file or an S_ISBLK blockdev, the swap * extent list operates in PAGE_SIZE disk blocks. Both S_ISREG and S_ISBLK * swapfiles are handled *identically* after swapon time. * * For S_ISREG swapfiles, setup_swap_extents() will walk all the file's blocks * and will parse them into an ordered extent list, in PAGE_SIZE chunks. If * some stray blocks are found which do not fall within the PAGE_SIZE alignment * requirements, they are simply tossed out - we will never use those blocks * for swapping. * |
b0d9bcd4b [PATCH] swap: upd... |
993 |
* For S_ISREG swapfiles we set S_SWAPFILE across the life of the swapon. This |
1da177e4c Linux-2.6.12-rc2 |
994 995 996 997 998 999 1000 1001 1002 1003 |
* prevents root from shooting her foot off by ftruncating an in-use swapfile, * which will scribble on the fs. * * The amount of disk space which a single swap extent represents varies. * Typically it is in the 1-4 megabyte range. So we can have hundreds of * extents in the list. To avoid much list walking, we cache the previous * search location in `curr_swap_extent', and start new searches from there. * This is extremely effective. The average number of iterations in * map_swap_page() has been measured at about 0.3 per page. - akpm. */ |
53092a740 [PATCH] swap: sho... |
1004 |
static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) |
1da177e4c Linux-2.6.12-rc2 |
1005 1006 1007 1008 1009 1010 1011 |
{ struct inode *inode; unsigned blocks_per_page; unsigned long page_no; unsigned blkbits; sector_t probe_block; sector_t last_block; |
53092a740 [PATCH] swap: sho... |
1012 1013 1014 |
sector_t lowest_block = -1; sector_t highest_block = 0; int nr_extents = 0; |
1da177e4c Linux-2.6.12-rc2 |
1015 1016 1017 1018 1019 |
int ret; inode = sis->swap_file->f_mapping->host; if (S_ISBLK(inode->i_mode)) { ret = add_swap_extent(sis, 0, sis->max, 0); |
53092a740 [PATCH] swap: sho... |
1020 |
*span = sis->pages; |
1da177e4c Linux-2.6.12-rc2 |
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 |
goto done; } blkbits = inode->i_blkbits; blocks_per_page = PAGE_SIZE >> blkbits; /* * Map all the blocks into the extent list. This code doesn't try * to be very smart. */ probe_block = 0; page_no = 0; last_block = i_size_read(inode) >> blkbits; while ((probe_block + blocks_per_page) <= last_block && page_no < sis->max) { unsigned block_in_page; sector_t first_block; first_block = bmap(inode, probe_block); if (first_block == 0) goto bad_bmap; /* * It must be PAGE_SIZE aligned on-disk */ if (first_block & (blocks_per_page - 1)) { probe_block++; goto reprobe; } for (block_in_page = 1; block_in_page < blocks_per_page; block_in_page++) { sector_t block; block = bmap(inode, probe_block + block_in_page); if (block == 0) goto bad_bmap; if (block != first_block + block_in_page) { /* Discontiguity */ probe_block++; goto reprobe; } } |
53092a740 [PATCH] swap: sho... |
1064 1065 1066 1067 1068 1069 1070 |
first_block >>= (PAGE_SHIFT - blkbits); if (page_no) { /* exclude the header page */ if (first_block < lowest_block) lowest_block = first_block; if (first_block > highest_block) highest_block = first_block; } |
1da177e4c Linux-2.6.12-rc2 |
1071 1072 1073 |
/* * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks */ |
53092a740 [PATCH] swap: sho... |
1074 1075 |
ret = add_swap_extent(sis, page_no, 1, first_block); if (ret < 0) |
1da177e4c Linux-2.6.12-rc2 |
1076 |
goto out; |
53092a740 [PATCH] swap: sho... |
1077 |
nr_extents += ret; |
1da177e4c Linux-2.6.12-rc2 |
1078 1079 1080 1081 1082 |
page_no++; probe_block += blocks_per_page; reprobe: continue; } |
53092a740 [PATCH] swap: sho... |
1083 1084 |
ret = nr_extents; *span = 1 + highest_block - lowest_block; |
1da177e4c Linux-2.6.12-rc2 |
1085 |
if (page_no == 0) |
e2244ec2e [PATCH] swap: cor... |
1086 |
page_no = 1; /* force Empty message */ |
1da177e4c Linux-2.6.12-rc2 |
1087 |
sis->max = page_no; |
e2244ec2e [PATCH] swap: cor... |
1088 |
sis->pages = page_no - 1; |
1da177e4c Linux-2.6.12-rc2 |
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 |
sis->highest_bit = page_no - 1; done: sis->curr_swap_extent = list_entry(sis->extent_list.prev, struct swap_extent, list); goto out; bad_bmap: printk(KERN_ERR "swapon: swapfile has holes "); ret = -EINVAL; out: return ret; } #if 0 /* We don't need this yet */ #include <linux/backing-dev.h> int page_queue_congested(struct page *page) { struct backing_dev_info *bdi; BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ if (PageSwapCache(page)) { |
4c21e2f24 [PATCH] mm: split... |
1111 |
swp_entry_t entry = { .val = page_private(page) }; |
1da177e4c Linux-2.6.12-rc2 |
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 |
struct swap_info_struct *sis; sis = get_swap_info_struct(swp_type(entry)); bdi = sis->bdev->bd_inode->i_mapping->backing_dev_info; } else bdi = page->mapping->backing_dev_info; return bdi_write_congested(bdi); } #endif asmlinkage long sys_swapoff(const char __user * specialfile) { struct swap_info_struct * p = NULL; unsigned short *swap_map; struct file *swap_file, *victim; struct address_space *mapping; struct inode *inode; char * pathname; int i, type, prev; int err; if (!capable(CAP_SYS_ADMIN)) return -EPERM; pathname = getname(specialfile); err = PTR_ERR(pathname); if (IS_ERR(pathname)) goto out; victim = filp_open(pathname, O_RDWR|O_LARGEFILE, 0); putname(pathname); err = PTR_ERR(victim); if (IS_ERR(victim)) goto out; mapping = victim->f_mapping; prev = -1; |
5d337b919 [PATCH] swap: swa... |
1149 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 |
for (type = swap_list.head; type >= 0; type = swap_info[type].next) { p = swap_info + type; if ((p->flags & SWP_ACTIVE) == SWP_ACTIVE) { if (p->swap_file->f_mapping == mapping) break; } prev = type; } if (type < 0) { err = -EINVAL; |
5d337b919 [PATCH] swap: swa... |
1160 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1161 1162 1163 1164 1165 1166 |
goto out_dput; } if (!security_vm_enough_memory(p->pages)) vm_unacct_memory(p->pages); else { err = -ENOMEM; |
5d337b919 [PATCH] swap: swa... |
1167 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 |
goto out_dput; } if (prev < 0) { swap_list.head = p->next; } else { swap_info[prev].next = p->next; } if (type == swap_list.next) { /* just pick something that's safe... */ swap_list.next = swap_list.head; } nr_swap_pages -= p->pages; total_swap_pages -= p->pages; p->flags &= ~SWP_WRITEOK; |
5d337b919 [PATCH] swap: swa... |
1182 |
spin_unlock(&swap_lock); |
fb4f88dca [PATCH] swap: get... |
1183 |
|
1da177e4c Linux-2.6.12-rc2 |
1184 1185 1186 |
current->flags |= PF_SWAPOFF; err = try_to_unuse(type); current->flags &= ~PF_SWAPOFF; |
1da177e4c Linux-2.6.12-rc2 |
1187 1188 |
if (err) { /* re-insert swap space back into swap_list */ |
5d337b919 [PATCH] swap: swa... |
1189 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 |
for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next) if (p->prio >= swap_info[i].prio) break; p->next = i; if (prev < 0) swap_list.head = swap_list.next = p - swap_info; else swap_info[prev].next = p - swap_info; nr_swap_pages += p->pages; total_swap_pages += p->pages; p->flags |= SWP_WRITEOK; |
5d337b919 [PATCH] swap: swa... |
1201 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1202 1203 |
goto out_dput; } |
52b7efdbe [PATCH] swap: sca... |
1204 1205 1206 1207 |
/* wait for any unplug function to finish */ down_write(&swap_unplug_sem); up_write(&swap_unplug_sem); |
5d337b919 [PATCH] swap: swa... |
1208 |
destroy_swap_extents(p); |
fc0abb145 [PATCH] sem2mutex... |
1209 |
mutex_lock(&swapon_mutex); |
5d337b919 [PATCH] swap: swa... |
1210 1211 |
spin_lock(&swap_lock); drain_mmlist(); |
52b7efdbe [PATCH] swap: sca... |
1212 |
/* wait for anyone still in scan_swap_map */ |
52b7efdbe [PATCH] swap: sca... |
1213 1214 |
p->highest_bit = 0; /* cuts scans short */ while (p->flags >= SWP_SCANNING) { |
5d337b919 [PATCH] swap: swa... |
1215 |
spin_unlock(&swap_lock); |
13e4b57f6 [PATCH] mm: fix-u... |
1216 |
schedule_timeout_uninterruptible(1); |
5d337b919 [PATCH] swap: swa... |
1217 |
spin_lock(&swap_lock); |
52b7efdbe [PATCH] swap: sca... |
1218 |
} |
52b7efdbe [PATCH] swap: sca... |
1219 |
|
1da177e4c Linux-2.6.12-rc2 |
1220 1221 1222 1223 1224 1225 |
swap_file = p->swap_file; p->swap_file = NULL; p->max = 0; swap_map = p->swap_map; p->swap_map = NULL; p->flags = 0; |
5d337b919 [PATCH] swap: swa... |
1226 |
spin_unlock(&swap_lock); |
fc0abb145 [PATCH] sem2mutex... |
1227 |
mutex_unlock(&swapon_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1228 1229 1230 1231 1232 1233 1234 |
vfree(swap_map); inode = mapping->host; if (S_ISBLK(inode->i_mode)) { struct block_device *bdev = I_BDEV(inode); set_blocksize(bdev, p->old_block_size); bd_release(bdev); } else { |
1b1dcc1b5 [PATCH] mutex sub... |
1235 |
mutex_lock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1236 |
inode->i_flags &= ~S_SWAPFILE; |
1b1dcc1b5 [PATCH] mutex sub... |
1237 |
mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 |
} filp_close(swap_file, NULL); err = 0; out_dput: filp_close(victim, NULL); out: return err; } #ifdef CONFIG_PROC_FS /* iterator */ static void *swap_start(struct seq_file *swap, loff_t *pos) { struct swap_info_struct *ptr = swap_info; int i; loff_t l = *pos; |
fc0abb145 [PATCH] sem2mutex... |
1255 |
mutex_lock(&swapon_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 |
for (i = 0; i < nr_swapfiles; i++, ptr++) { if (!(ptr->flags & SWP_USED) || !ptr->swap_map) continue; if (!l--) return ptr; } return NULL; } static void *swap_next(struct seq_file *swap, void *v, loff_t *pos) { struct swap_info_struct *ptr = v; struct swap_info_struct *endptr = swap_info + nr_swapfiles; for (++ptr; ptr < endptr; ptr++) { if (!(ptr->flags & SWP_USED) || !ptr->swap_map) continue; ++*pos; return ptr; } return NULL; } static void swap_stop(struct seq_file *swap, void *v) { |
fc0abb145 [PATCH] sem2mutex... |
1284 |
mutex_unlock(&swapon_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 |
} static int swap_show(struct seq_file *swap, void *v) { struct swap_info_struct *ptr = v; struct file *file; int len; if (v == swap_info) seq_puts(swap, "Filename\t\t\t\tType\t\tSize\tUsed\tPriority "); file = ptr->swap_file; len = seq_path(swap, file->f_vfsmnt, file->f_dentry, " \t \\"); |
6eb396dc4 [PATCH] swap: swa... |
1300 1301 |
seq_printf(swap, "%*s%s\t%u\t%u\t%d ", |
1da177e4c Linux-2.6.12-rc2 |
1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 |
len < 40 ? 40 - len : 1, " ", S_ISBLK(file->f_dentry->d_inode->i_mode) ? "partition" : "file\t", ptr->pages << (PAGE_SHIFT - 10), ptr->inuse_pages << (PAGE_SHIFT - 10), ptr->prio); return 0; } static struct seq_operations swaps_op = { .start = swap_start, .next = swap_next, .stop = swap_stop, .show = swap_show }; static int swaps_open(struct inode *inode, struct file *file) { return seq_open(file, &swaps_op); } static struct file_operations proc_swaps_operations = { .open = swaps_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; static int __init procswaps_init(void) { struct proc_dir_entry *entry; entry = create_proc_entry("swaps", 0, NULL); if (entry) entry->proc_fops = &proc_swaps_operations; return 0; } __initcall(procswaps_init); #endif /* CONFIG_PROC_FS */ /* * Written 01/25/92 by Simmule Turner, heavily changed by Linus. * * The swapon system call */ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) { struct swap_info_struct * p; char *name = NULL; struct block_device *bdev = NULL; struct file *swap_file = NULL; struct address_space *mapping; unsigned int type; int i, prev; int error; static int least_priority; union swap_header *swap_header = NULL; int swap_header_version; |
6eb396dc4 [PATCH] swap: swa... |
1360 1361 |
unsigned int nr_good_pages = 0; int nr_extents = 0; |
53092a740 [PATCH] swap: sho... |
1362 |
sector_t span; |
1da177e4c Linux-2.6.12-rc2 |
1363 1364 1365 1366 1367 1368 1369 1370 1371 |
unsigned long maxpages = 1; int swapfilesize; unsigned short *swap_map; struct page *page = NULL; struct inode *inode = NULL; int did_down = 0; if (!capable(CAP_SYS_ADMIN)) return -EPERM; |
5d337b919 [PATCH] swap: swa... |
1372 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1373 1374 1375 1376 1377 |
p = swap_info; for (type = 0 ; type < nr_swapfiles ; type++,p++) if (!(p->flags & SWP_USED)) break; error = -EPERM; |
0697212a4 [PATCH] Swapless ... |
1378 |
if (type >= MAX_SWAPFILES) { |
5d337b919 [PATCH] swap: swa... |
1379 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1380 1381 1382 1383 1384 1385 |
goto out; } if (type >= nr_swapfiles) nr_swapfiles = type+1; INIT_LIST_HEAD(&p->extent_list); p->flags = SWP_USED; |
1da177e4c Linux-2.6.12-rc2 |
1386 1387 1388 1389 1390 1391 1392 |
p->swap_file = NULL; p->old_block_size = 0; p->swap_map = NULL; p->lowest_bit = 0; p->highest_bit = 0; p->cluster_nr = 0; p->inuse_pages = 0; |
1da177e4c Linux-2.6.12-rc2 |
1393 1394 1395 1396 1397 1398 1399 |
p->next = -1; if (swap_flags & SWAP_FLAG_PREFER) { p->prio = (swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT; } else { p->prio = --least_priority; } |
5d337b919 [PATCH] swap: swa... |
1400 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 |
name = getname(specialfile); error = PTR_ERR(name); if (IS_ERR(name)) { name = NULL; goto bad_swap_2; } swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0); error = PTR_ERR(swap_file); if (IS_ERR(swap_file)) { swap_file = NULL; goto bad_swap_2; } p->swap_file = swap_file; mapping = swap_file->f_mapping; inode = mapping->host; error = -EBUSY; for (i = 0; i < nr_swapfiles; i++) { struct swap_info_struct *q = &swap_info[i]; if (i == type || !q->swap_file) continue; if (mapping == q->swap_file->f_mapping) goto bad_swap; } error = -EINVAL; if (S_ISBLK(inode->i_mode)) { bdev = I_BDEV(inode); error = bd_claim(bdev, sys_swapon); if (error < 0) { bdev = NULL; |
f7b3a4359 [PATCH] Fix bd_cl... |
1434 |
error = -EINVAL; |
1da177e4c Linux-2.6.12-rc2 |
1435 1436 1437 1438 1439 1440 1441 1442 1443 |
goto bad_swap; } p->old_block_size = block_size(bdev); error = set_blocksize(bdev, PAGE_SIZE); if (error < 0) goto bad_swap; p->bdev = bdev; } else if (S_ISREG(inode->i_mode)) { p->bdev = inode->i_sb->s_bdev; |
1b1dcc1b5 [PATCH] mutex sub... |
1444 |
mutex_lock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 |
did_down = 1; if (IS_SWAPFILE(inode)) { error = -EBUSY; goto bad_swap; } } else { goto bad_swap; } swapfilesize = i_size_read(inode) >> PAGE_SHIFT; /* * Read the swap header. */ if (!mapping->a_ops->readpage) { error = -EINVAL; goto bad_swap; } |
090d2b185 [PATCH] read_mapp... |
1463 |
page = read_mapping_page(mapping, 0, swap_file); |
1da177e4c Linux-2.6.12-rc2 |
1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 |
if (IS_ERR(page)) { error = PTR_ERR(page); goto bad_swap; } wait_on_page_locked(page); if (!PageUptodate(page)) goto bad_swap; kmap(page); swap_header = page_address(page); if (!memcmp("SWAP-SPACE",swap_header->magic.magic,10)) swap_header_version = 1; else if (!memcmp("SWAPSPACE2",swap_header->magic.magic,10)) swap_header_version = 2; else { |
e97a31117 add missing print... |
1479 1480 |
printk(KERN_ERR "Unable to find swap-space signature "); |
1da177e4c Linux-2.6.12-rc2 |
1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 |
error = -EINVAL; goto bad_swap; } switch (swap_header_version) { case 1: printk(KERN_ERR "version 0 swap is no longer supported. " "Use mkswap -v1 %s ", name); error = -EINVAL; goto bad_swap; case 2: /* Check the swap header's sub-version and the size of the swap file and bad block lists */ if (swap_header->info.version != 1) { printk(KERN_WARNING "Unable to handle swap header version %d ", swap_header->info.version); error = -EINVAL; goto bad_swap; } p->lowest_bit = 1; |
52b7efdbe [PATCH] swap: sca... |
1505 |
p->cluster_next = 1; |
1da177e4c Linux-2.6.12-rc2 |
1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 |
/* * Find out how many pages are allowed for a single swap * device. There are two limiting factors: 1) the number of * bits for the swap offset in the swp_entry_t type and * 2) the number of bits in the a swap pte as defined by * the different architectures. In order to find the * largest possible bit mask a swap entry with swap type 0 * and swap offset ~0UL is created, encoded to a swap pte, * decoded to a swp_entry_t again and finally the swap * offset is extracted. This will mask all the bits from * the initial ~0UL mask that can't be encoded in either * the swp_entry_t or the architecture definition of a * swap pte. */ maxpages = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0,~0UL)))) - 1; if (maxpages > swap_header->info.last_page) maxpages = swap_header->info.last_page; p->highest_bit = maxpages - 1; error = -EINVAL; |
e2244ec2e [PATCH] swap: cor... |
1526 1527 1528 1529 |
if (!maxpages) goto bad_swap; if (swap_header->info.nr_badpages && S_ISREG(inode->i_mode)) goto bad_swap; |
1da177e4c Linux-2.6.12-rc2 |
1530 1531 |
if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) goto bad_swap; |
cd105df45 [PATCH] mm: clean... |
1532 |
|
1da177e4c Linux-2.6.12-rc2 |
1533 1534 1535 1536 1537 1538 1539 1540 |
/* OK, set up the swap map and apply the bad block list */ if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { error = -ENOMEM; goto bad_swap; } error = 0; memset(p->swap_map, 0, maxpages * sizeof(short)); |
cd105df45 [PATCH] mm: clean... |
1541 1542 1543 |
for (i = 0; i < swap_header->info.nr_badpages; i++) { int page_nr = swap_header->info.badpages[i]; if (page_nr <= 0 || page_nr >= swap_header->info.last_page) |
1da177e4c Linux-2.6.12-rc2 |
1544 1545 |
error = -EINVAL; else |
cd105df45 [PATCH] mm: clean... |
1546 |
p->swap_map[page_nr] = SWAP_MAP_BAD; |
1da177e4c Linux-2.6.12-rc2 |
1547 1548 1549 1550 |
} nr_good_pages = swap_header->info.last_page - swap_header->info.nr_badpages - 1 /* header page */; |
cd105df45 [PATCH] mm: clean... |
1551 |
if (error) |
1da177e4c Linux-2.6.12-rc2 |
1552 1553 |
goto bad_swap; } |
e2244ec2e [PATCH] swap: cor... |
1554 |
|
1da177e4c Linux-2.6.12-rc2 |
1555 1556 1557 1558 1559 1560 1561 |
if (swapfilesize && maxpages > swapfilesize) { printk(KERN_WARNING "Swap area shorter than signature indicates "); error = -EINVAL; goto bad_swap; } |
e2244ec2e [PATCH] swap: cor... |
1562 1563 1564 1565 |
if (nr_good_pages) { p->swap_map[0] = SWAP_MAP_BAD; p->max = maxpages; p->pages = nr_good_pages; |
53092a740 [PATCH] swap: sho... |
1566 1567 1568 |
nr_extents = setup_swap_extents(p, &span); if (nr_extents < 0) { error = nr_extents; |
e2244ec2e [PATCH] swap: cor... |
1569 |
goto bad_swap; |
53092a740 [PATCH] swap: sho... |
1570 |
} |
e2244ec2e [PATCH] swap: cor... |
1571 1572 |
nr_good_pages = p->pages; } |
1da177e4c Linux-2.6.12-rc2 |
1573 1574 1575 1576 1577 1578 |
if (!nr_good_pages) { printk(KERN_WARNING "Empty swap-file "); error = -EINVAL; goto bad_swap; } |
1da177e4c Linux-2.6.12-rc2 |
1579 |
|
fc0abb145 [PATCH] sem2mutex... |
1580 |
mutex_lock(&swapon_mutex); |
5d337b919 [PATCH] swap: swa... |
1581 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1582 1583 1584 |
p->flags = SWP_ACTIVE; nr_swap_pages += nr_good_pages; total_swap_pages += nr_good_pages; |
53092a740 [PATCH] swap: sho... |
1585 |
|
6eb396dc4 [PATCH] swap: swa... |
1586 |
printk(KERN_INFO "Adding %uk swap on %s. " |
53092a740 [PATCH] swap: sho... |
1587 1588 1589 1590 |
"Priority:%d extents:%d across:%lluk ", nr_good_pages<<(PAGE_SHIFT-10), name, p->prio, nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10)); |
1da177e4c Linux-2.6.12-rc2 |
1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 |
/* 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; } |
5d337b919 [PATCH] swap: swa... |
1606 |
spin_unlock(&swap_lock); |
fc0abb145 [PATCH] sem2mutex... |
1607 |
mutex_unlock(&swapon_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1608 1609 1610 1611 1612 1613 1614 |
error = 0; goto out; bad_swap: if (bdev) { set_blocksize(bdev, p->old_block_size); bd_release(bdev); } |
4cd3bb10f [PATCH] swap: mov... |
1615 |
destroy_swap_extents(p); |
1da177e4c Linux-2.6.12-rc2 |
1616 |
bad_swap_2: |
5d337b919 [PATCH] swap: swa... |
1617 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1618 1619 1620 1621 1622 1623 |
swap_map = p->swap_map; p->swap_file = NULL; p->swap_map = NULL; p->flags = 0; if (!(swap_flags & SWAP_FLAG_PREFER)) ++least_priority; |
5d337b919 [PATCH] swap: swa... |
1624 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 |
vfree(swap_map); if (swap_file) filp_close(swap_file, NULL); out: if (page && !IS_ERR(page)) { kunmap(page); page_cache_release(page); } if (name) putname(name); if (did_down) { if (!error) inode->i_flags |= S_SWAPFILE; |
1b1dcc1b5 [PATCH] mutex sub... |
1638 |
mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
1639 1640 1641 1642 1643 1644 1645 1646 |
} return error; } void si_swapinfo(struct sysinfo *val) { unsigned int i; unsigned long nr_to_be_unused = 0; |
5d337b919 [PATCH] swap: swa... |
1647 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1648 1649 1650 1651 1652 1653 1654 1655 |
for (i = 0; i < nr_swapfiles; i++) { if (!(swap_info[i].flags & SWP_USED) || (swap_info[i].flags & SWP_WRITEOK)) continue; nr_to_be_unused += swap_info[i].inuse_pages; } val->freeswap = nr_swap_pages + nr_to_be_unused; val->totalswap = total_swap_pages + nr_to_be_unused; |
5d337b919 [PATCH] swap: swa... |
1656 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 |
} /* * Verify that a swap entry is valid and increment its swap map count. * * Note: if swap_map[] reaches SWAP_MAP_MAX the entries are treated as * "permanent", but will be reclaimed by the next swapoff. */ int swap_duplicate(swp_entry_t entry) { struct swap_info_struct * p; unsigned long offset, type; int result = 0; |
0697212a4 [PATCH] Swapless ... |
1670 1671 |
if (is_migration_entry(entry)) return 1; |
1da177e4c Linux-2.6.12-rc2 |
1672 1673 1674 1675 1676 |
type = swp_type(entry); if (type >= nr_swapfiles) goto bad_file; p = type + swap_info; offset = swp_offset(entry); |
5d337b919 [PATCH] swap: swa... |
1677 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 |
if (offset < p->max && p->swap_map[offset]) { if (p->swap_map[offset] < SWAP_MAP_MAX - 1) { p->swap_map[offset]++; result = 1; } else if (p->swap_map[offset] <= SWAP_MAP_MAX) { if (swap_overflow++ < 5) printk(KERN_WARNING "swap_dup: swap entry overflow "); p->swap_map[offset] = SWAP_MAP_MAX; result = 1; } } |
5d337b919 [PATCH] swap: swa... |
1690 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 |
out: return result; bad_file: printk(KERN_ERR "swap_dup: %s%08lx ", Bad_file, entry.val); goto out; } struct swap_info_struct * get_swap_info_struct(unsigned type) { return &swap_info[type]; } /* |
5d337b919 [PATCH] swap: swa... |
1707 |
* swap_lock prevents swap_map being freed. Don't grab an extra |
1da177e4c Linux-2.6.12-rc2 |
1708 1709 1710 1711 |
* reference on the swaphandle, it doesn't matter if it becomes unused. */ int valid_swaphandles(swp_entry_t entry, unsigned long *offset) { |
3f9e7949f [PATCH] valid_swa... |
1712 1713 |
int our_page_cluster = page_cluster; int ret = 0, i = 1 << our_page_cluster; |
1da177e4c Linux-2.6.12-rc2 |
1714 1715 |
unsigned long toff; struct swap_info_struct *swapdev = swp_type(entry) + swap_info; |
3f9e7949f [PATCH] valid_swa... |
1716 |
if (!our_page_cluster) /* no readahead */ |
1da177e4c Linux-2.6.12-rc2 |
1717 |
return 0; |
3f9e7949f [PATCH] valid_swa... |
1718 |
toff = (swp_offset(entry) >> our_page_cluster) << our_page_cluster; |
1da177e4c Linux-2.6.12-rc2 |
1719 1720 1721 |
if (!toff) /* first page is swap header */ toff++, i--; *offset = toff; |
5d337b919 [PATCH] swap: swa... |
1722 |
spin_lock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 |
do { /* Don't read-ahead past the end of the swap area */ if (toff >= swapdev->max) break; /* Don't read in free or bad pages */ if (!swapdev->swap_map[toff]) break; if (swapdev->swap_map[toff] == SWAP_MAP_BAD) break; toff++; ret++; } while (--i); |
5d337b919 [PATCH] swap: swa... |
1735 |
spin_unlock(&swap_lock); |
1da177e4c Linux-2.6.12-rc2 |
1736 1737 |
return ret; } |