diff options
Diffstat (limited to 'mm/swap_state.c')
| -rw-r--r-- | mm/swap_state.c | 153 |
1 files changed, 71 insertions, 82 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index b52635601dfe..ec42f01a8d02 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -10,6 +10,7 @@ #include <linux/mm.h> #include <linux/kernel_stat.h> #include <linux/swap.h> +#include <linux/swapops.h> #include <linux/init.h> #include <linux/pagemap.h> #include <linux/buffer_head.h> @@ -51,26 +52,22 @@ static struct { unsigned long del_total; unsigned long find_success; unsigned long find_total; - unsigned long noent_race; - unsigned long exist_race; } swap_cache_info; void show_swap_cache_info(void) { - printk("Swap cache: add %lu, delete %lu, find %lu/%lu, race %lu+%lu\n", + printk("Swap cache: 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, - swap_cache_info.noent_race, swap_cache_info.exist_race); + swap_cache_info.find_success, swap_cache_info.find_total); printk("Free swap = %lukB\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 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, - gfp_t gfp_mask) +int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) { int error; @@ -88,6 +85,7 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry, 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); radix_tree_preload_end(); @@ -95,31 +93,6 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry, return error; } -static int add_to_swap_cache(struct page *page, swp_entry_t entry) -{ - int error; - - BUG_ON(PageLocked(page)); - if (!swap_duplicate(entry)) { - INC_CACHE_INFO(noent_race); - return -ENOENT; - } - SetPageLocked(page); - error = __add_to_swap_cache(page, entry, GFP_KERNEL); - /* - * Anon pages are already on the LRU, we don't run lru_cache_add here. - */ - if (error) { - ClearPageLocked(page); - swap_free(entry); - if (error == -EEXIST) - INC_CACHE_INFO(exist_race); - return error; - } - INC_CACHE_INFO(add_total); - return 0; -} - /* * This must be called only on pages that have * been verified to be in the swap cache. @@ -152,6 +125,7 @@ int add_to_swap(struct page * page, gfp_t gfp_mask) int err; BUG_ON(!PageLocked(page)); + BUG_ON(!PageUptodate(page)); for (;;) { entry = get_swap_page(); @@ -169,18 +143,15 @@ int add_to_swap(struct page * page, gfp_t gfp_mask) /* * Add it to the swap cache and mark it dirty */ - err = __add_to_swap_cache(page, entry, + err = add_to_swap_cache(page, entry, gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN); switch (err) { case 0: /* Success */ - SetPageUptodate(page); SetPageDirty(page); - INC_CACHE_INFO(add_total); return 1; case -EEXIST: /* Raced with "speculative" read_swap_cache_async */ - INC_CACHE_INFO(exist_race); swap_free(entry); continue; default: @@ -211,40 +182,6 @@ void delete_from_swap_cache(struct page *page) page_cache_release(page); } -/* - * Strange swizzling function only for use by shmem_writepage - */ -int move_to_swap_cache(struct page *page, swp_entry_t entry) -{ - int err = __add_to_swap_cache(page, entry, GFP_ATOMIC); - if (!err) { - remove_from_page_cache(page); - page_cache_release(page); /* pagecache ref */ - if (!swap_duplicate(entry)) - BUG(); - SetPageDirty(page); - INC_CACHE_INFO(add_total); - } else if (err == -EEXIST) - INC_CACHE_INFO(exist_race); - return err; -} - -/* - * Strange swizzling function for shmem_getpage (and shmem_unuse) - */ -int move_from_swap_cache(struct page *page, unsigned long index, - struct address_space *mapping) -{ - int err = add_to_page_cache(page, mapping, index, GFP_ATOMIC); - if (!err) { - delete_from_swap_cache(page); - /* shift page from clean_pages to dirty_pages list */ - ClearPageDirty(page); - set_page_dirty(page); - } - return err; -} - /* * If we are the only user, then try to free up the swap cache. * @@ -317,7 +254,7 @@ struct page * lookup_swap_cache(swp_entry_t entry) * A failure return means that either the page allocation failed or that * the swap entry is no longer in use. */ -struct page *read_swap_cache_async(swp_entry_t entry, +struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, struct vm_area_struct *vma, unsigned long addr) { struct page *found_page, *new_page = NULL; @@ -337,23 +274,27 @@ struct page *read_swap_cache_async(swp_entry_t entry, * Get a new page to read into from swap. */ if (!new_page) { - new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, - vma, addr); + new_page = alloc_page_vma(gfp_mask, vma, addr); if (!new_page) break; /* Out of memory */ } /* + * Swap entry may have been freed since our caller observed it. + */ + if (!swap_duplicate(entry)) + break; + + /* * Associate the page with swap entry in the swap cache. - * May fail (-ENOENT) if swap entry has been freed since - * our caller observed it. 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 by try_to_swap_out (or shmem_writepage) re-using - * the just freed swap entry for an existing page. + * 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. */ - err = add_to_swap_cache(new_page, entry); + SetPageLocked(new_page); + err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL); if (!err) { /* * Initiate read into locked page and return. @@ -362,9 +303,57 @@ struct page *read_swap_cache_async(swp_entry_t entry, swap_readpage(NULL, new_page); return new_page; } - } while (err != -ENOENT && err != -ENOMEM); + ClearPageLocked(new_page); + swap_free(entry); + } while (err != -ENOMEM); if (new_page) page_cache_release(new_page); return found_page; } + +/** + * swapin_readahead - swap in pages in hope we need them soon + * @entry: swap entry of this memory + * @vma: user vma this address belongs to + * @addr: target address for mempolicy + * + * Returns the struct page for entry and addr, after queueing swapin. + * + * Primitive swap readahead code. We simply read an aligned block of + * (1 << page_cluster) entries in the swap area. This method is chosen + * because it doesn't cost us any seek time. We also make sure to queue + * the 'original' request together with the readahead ones... + * + * This has been extended to use the NUMA policies from the mm triggering + * the readahead. + * + * Caller must hold down_read on the vma->vm_mm if vma is not NULL. + */ +struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, + struct vm_area_struct *vma, unsigned long addr) +{ + int nr_pages; + struct page *page; + unsigned long offset; + unsigned long end_offset; + + /* + * Get starting offset for readaround, and number of pages to read. + * Adjust starting address by readbehind (for NUMA interleave case)? + * No, it's very unlikely that swap layout would follow vma layout, + * more likely that neighbouring swap pages came from the same node: + * so use the same "addr" to choose the same node for each swap read. + */ + nr_pages = valid_swaphandles(entry, &offset); + for (end_offset = offset + nr_pages; offset < end_offset; offset++) { + /* Ok, do the async read-ahead now */ + page = read_swap_cache_async(swp_entry(swp_type(entry), offset), + gfp_mask, vma, addr); + if (!page) + break; + page_cache_release(page); + } + lru_add_drain(); /* Push any new pages onto the LRU now */ + return read_swap_cache_async(entry, gfp_mask, vma, addr); +} |