*/
#include <linux/module.h>
#include <linux/mm.h>
+#include <linux/gfp.h>
#include <linux/kernel_stat.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
#include <linux/migrate.h>
+#include <linux/page_cgroup.h>
#include <asm/pgtable.h>
/*
* swapper_space is a fiction, retained to simplify the path through
- * vmscan's shrink_page_list, to make sync_page look nicer, and to allow
- * future use of radix_tree tags in the swap cache.
+ * vmscan's shrink_page_list.
*/
static const struct address_space_operations swap_aops = {
.writepage = swap_writepage,
- .sync_page = block_sync_page,
.set_page_dirty = __set_page_dirty_nobuffers,
.migratepage = migrate_page,
};
static struct backing_dev_info swap_backing_dev_info = {
- .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
- .unplug_io_fn = swap_unplug_io_fn,
+ .name = "swap",
+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
};
struct address_space swapper_space = {
.page_tree = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
- .tree_lock = __RW_LOCK_UNLOCKED(swapper_space.tree_lock),
+ .tree_lock = __SPIN_LOCK_UNLOCKED(swapper_space.tree_lock),
.a_ops = &swap_aops,
.i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear),
.backing_dev_info = &swap_backing_dev_info,
void show_swap_cache_info(void)
{
- printk("Swap cache: add %lu, delete %lu, find %lu/%lu\n",
+ printk("%lu pages in swap cache\n", total_swapcache_pages);
+ printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu\n",
swap_cache_info.add_total, swap_cache_info.del_total,
swap_cache_info.find_success, swap_cache_info.find_total);
- printk("Free swap = %lukB\n", nr_swap_pages << (PAGE_SHIFT - 10));
+ printk("Free swap = %ldkB\n", nr_swap_pages << (PAGE_SHIFT - 10));
printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10));
}
/*
- * add_to_swap_cache resembles add_to_page_cache on swapper_space,
+ * __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
+static int __add_to_swap_cache(struct page *page, swp_entry_t entry)
+{
+ int error;
+
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(PageSwapCache(page));
+ VM_BUG_ON(!PageSwapBacked(page));
+
+ page_cache_get(page);
+ SetPageSwapCache(page);
+ set_page_private(page, entry.val);
+
+ spin_lock_irq(&swapper_space.tree_lock);
+ error = radix_tree_insert(&swapper_space.page_tree, entry.val, page);
+ if (likely(!error)) {
+ total_swapcache_pages++;
+ __inc_zone_page_state(page, NR_FILE_PAGES);
+ INC_CACHE_INFO(add_total);
+ }
+ spin_unlock_irq(&swapper_space.tree_lock);
+
+ if (unlikely(error)) {
+ /*
+ * Only the context which have set SWAP_HAS_CACHE flag
+ * would call add_to_swap_cache().
+ * So add_to_swap_cache() doesn't returns -EEXIST.
+ */
+ VM_BUG_ON(error == -EEXIST);
+ set_page_private(page, 0UL);
+ ClearPageSwapCache(page);
+ page_cache_release(page);
+ }
+
+ return error;
+}
+
+
int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
{
int error;
- BUG_ON(!PageLocked(page));
- BUG_ON(PageSwapCache(page));
- BUG_ON(PagePrivate(page));
error = radix_tree_preload(gfp_mask);
if (!error) {
- write_lock_irq(&swapper_space.tree_lock);
- error = radix_tree_insert(&swapper_space.page_tree,
- entry.val, page);
- if (!error) {
- page_cache_get(page);
- SetPageSwapCache(page);
- set_page_private(page, entry.val);
- total_swapcache_pages++;
- __inc_zone_page_state(page, NR_FILE_PAGES);
- INC_CACHE_INFO(add_total);
- }
- write_unlock_irq(&swapper_space.tree_lock);
+ error = __add_to_swap_cache(page, entry);
radix_tree_preload_end();
}
return error;
*/
void __delete_from_swap_cache(struct page *page)
{
- BUG_ON(!PageLocked(page));
- BUG_ON(!PageSwapCache(page));
- BUG_ON(PageWriteback(page));
- BUG_ON(PagePrivate(page));
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageSwapCache(page));
+ VM_BUG_ON(PageWriteback(page));
radix_tree_delete(&swapper_space.page_tree, page_private(page));
set_page_private(page, 0);
* Allocate swap space for the page and add the page to the
* swap cache. Caller needs to hold the page lock.
*/
-int add_to_swap(struct page * page, gfp_t gfp_mask)
+int add_to_swap(struct page *page)
{
swp_entry_t entry;
int err;
- BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageUptodate(page));
+
+ entry = get_swap_page();
+ if (!entry.val)
+ return 0;
- for (;;) {
- entry = get_swap_page();
- if (!entry.val)
+ if (unlikely(PageTransHuge(page)))
+ if (unlikely(split_huge_page(page))) {
+ swapcache_free(entry, NULL);
return 0;
+ }
+ /*
+ * Radix-tree node allocations from PF_MEMALLOC contexts could
+ * completely exhaust the page allocator. __GFP_NOMEMALLOC
+ * stops emergency reserves from being allocated.
+ *
+ * TODO: this could cause a theoretical memory reclaim
+ * deadlock in the swap out path.
+ */
+ /*
+ * Add it to the swap cache and mark it dirty
+ */
+ err = add_to_swap_cache(page, entry,
+ __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN);
+
+ if (!err) { /* Success */
+ SetPageDirty(page);
+ return 1;
+ } else { /* -ENOMEM radix-tree allocation failure */
/*
- * Radix-tree node allocations from PF_MEMALLOC contexts could
- * completely exhaust the page allocator. __GFP_NOMEMALLOC
- * stops emergency reserves from being allocated.
- *
- * TODO: this could cause a theoretical memory reclaim
- * deadlock in the swap out path.
- */
- /*
- * Add it to the swap cache and mark it dirty
+ * add_to_swap_cache() doesn't return -EEXIST, so we can safely
+ * clear SWAP_HAS_CACHE flag.
*/
- err = add_to_swap_cache(page, entry,
- gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN);
-
- switch (err) {
- case 0: /* Success */
- SetPageUptodate(page);
- SetPageDirty(page);
- return 1;
- case -EEXIST:
- /* Raced with "speculative" read_swap_cache_async */
- swap_free(entry);
- continue;
- default:
- /* -ENOMEM radix-tree allocation failure */
- swap_free(entry);
- return 0;
- }
+ swapcache_free(entry, NULL);
+ return 0;
}
}
entry.val = page_private(page);
- write_lock_irq(&swapper_space.tree_lock);
+ spin_lock_irq(&swapper_space.tree_lock);
__delete_from_swap_cache(page);
- write_unlock_irq(&swapper_space.tree_lock);
+ spin_unlock_irq(&swapper_space.tree_lock);
- swap_free(entry);
+ swapcache_free(entry, page);
page_cache_release(page);
}
* If we are the only user, then try to free up the swap cache.
*
* Its ok to check for PageSwapCache without the page lock
- * here because we are going to recheck again inside
- * exclusive_swap_page() _with_ the lock.
+ * here because we are going to recheck again inside
+ * try_to_free_swap() _with_ the lock.
* - Marcelo
*/
static inline void free_swap_cache(struct page *page)
{
- if (PageSwapCache(page) && !TestSetPageLocked(page)) {
- remove_exclusive_swap_page(page);
+ if (PageSwapCache(page) && !page_mapped(page) && trylock_page(page)) {
+ try_to_free_swap(page);
unlock_page(page);
}
}
}
/*
- * Swap entry may have been freed since our caller observed it.
+ * call radix_tree_preload() while we can wait.
*/
- if (!swap_duplicate(entry))
+ err = radix_tree_preload(gfp_mask & GFP_KERNEL);
+ if (err)
break;
/*
- * Associate the page with swap entry in the swap cache.
- * May fail (-EEXIST) if there is already a page associated
- * with this entry in the swap cache: added by a racing
- * read_swap_cache_async, or add_to_swap or shmem_writepage
- * re-using the just freed swap entry for an existing page.
- * May fail (-ENOMEM) if radix-tree node allocation failed.
+ * Swap entry may have been freed since our caller observed it.
*/
- SetPageLocked(new_page);
- err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
- if (!err) {
+ err = swapcache_prepare(entry);
+ if (err == -EEXIST) { /* seems racy */
+ radix_tree_preload_end();
+ continue;
+ }
+ if (err) { /* swp entry is obsolete ? */
+ radix_tree_preload_end();
+ break;
+ }
+
+ /* May fail (-ENOMEM) if radix-tree node allocation failed. */
+ __set_page_locked(new_page);
+ SetPageSwapBacked(new_page);
+ err = __add_to_swap_cache(new_page, entry);
+ if (likely(!err)) {
+ radix_tree_preload_end();
/*
* Initiate read into locked page and return.
*/
- lru_cache_add_active(new_page);
- swap_readpage(NULL, new_page);
+ lru_cache_add_anon(new_page);
+ swap_readpage(new_page);
return new_page;
}
- ClearPageLocked(new_page);
- swap_free(entry);
+ radix_tree_preload_end();
+ ClearPageSwapBacked(new_page);
+ __clear_page_locked(new_page);
+ /*
+ * add_to_swap_cache() doesn't return -EEXIST, so we can safely
+ * clear SWAP_HAS_CACHE flag.
+ */
+ swapcache_free(entry, NULL);
} while (err != -ENOMEM);
if (new_page)
/**
* swapin_readahead - swap in pages in hope we need them soon
* @entry: swap entry of this memory
+ * @gfp_mask: memory allocation flags
* @vma: user vma this address belongs to
* @addr: target address for mempolicy
*
Code Review / linux-2.6.git / blobdiff