diff options
| -rw-r--r-- | include/linux/swap.h | 3 | ||||
| -rw-r--r-- | mm/swap_state.c | 37 | ||||
| -rw-r--r-- | mm/zswap.c | 73 |
3 files changed, 35 insertions, 78 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 2ce190709280..7ba7dccaf0e7 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -406,6 +406,9 @@ extern void free_pages_and_swap_cache(struct page **, int); extern struct page *lookup_swap_cache(swp_entry_t); extern struct page *read_swap_cache_async(swp_entry_t, gfp_t, struct vm_area_struct *vma, unsigned long addr); +extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t, + struct vm_area_struct *vma, unsigned long addr, + bool *new_page_allocated); extern struct page *swapin_readahead(swp_entry_t, gfp_t, struct vm_area_struct *vma, unsigned long addr); diff --git a/mm/swap_state.c b/mm/swap_state.c index 8bc8e66138da..d504adb7fa5f 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -288,17 +288,14 @@ struct page * lookup_swap_cache(swp_entry_t entry) return page; } -/* - * Locate a page of swap in physical memory, reserving swap cache space - * and reading the disk if it is not already cached. - * 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, gfp_t gfp_mask, - struct vm_area_struct *vma, unsigned long addr) +struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, + struct vm_area_struct *vma, unsigned long addr, + bool *new_page_allocated) { struct page *found_page, *new_page = NULL; + struct address_space *swapper_space = swap_address_space(entry); int err; + *new_page_allocated = false; do { /* @@ -306,8 +303,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, * called after lookup_swap_cache() failed, re-calling * that would confuse statistics. */ - found_page = find_get_page(swap_address_space(entry), - entry.val); + found_page = find_get_page(swapper_space, entry.val); if (found_page) break; @@ -366,7 +362,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, * Initiate read into locked page and return. */ lru_cache_add_anon(new_page); - swap_readpage(new_page); + *new_page_allocated = true; return new_page; } radix_tree_preload_end(); @@ -384,6 +380,25 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, return found_page; } +/* + * Locate a page of swap in physical memory, reserving swap cache space + * and reading the disk if it is not already cached. + * 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, gfp_t gfp_mask, + struct vm_area_struct *vma, unsigned long addr) +{ + bool page_was_allocated; + struct page *retpage = __read_swap_cache_async(entry, gfp_mask, + vma, addr, &page_was_allocated); + + if (page_was_allocated) + swap_readpage(retpage); + + return retpage; +} + static unsigned long swapin_nr_pages(unsigned long offset) { static unsigned long prev_offset; diff --git a/mm/zswap.c b/mm/zswap.c index 2d5727baed59..09208c7c86f3 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -446,75 +446,14 @@ enum zswap_get_swap_ret { static int zswap_get_swap_cache_page(swp_entry_t entry, struct page **retpage) { - struct page *found_page, *new_page = NULL; - struct address_space *swapper_space = swap_address_space(entry); - int err; + bool page_was_allocated; - *retpage = NULL; - do { - /* - * First check the swap cache. Since this is normally - * called after lookup_swap_cache() failed, re-calling - * that would confuse statistics. - */ - found_page = find_get_page(swapper_space, entry.val); - if (found_page) - break; - - /* - * Get a new page to read into from swap. - */ - if (!new_page) { - new_page = alloc_page(GFP_KERNEL); - if (!new_page) - break; /* Out of memory */ - } - - /* - * call radix_tree_preload() while we can wait. - */ - err = radix_tree_preload(GFP_KERNEL); - if (err) - break; - - /* - * Swap entry may have been freed since our caller observed it. - */ - 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(); - lru_cache_add_anon(new_page); - *retpage = new_page; - return ZSWAP_SWAPCACHE_NEW; - } - 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); - } while (err != -ENOMEM); - - if (new_page) - page_cache_release(new_page); - if (!found_page) + *retpage = __read_swap_cache_async(entry, GFP_KERNEL, + NULL, 0, &page_was_allocated); + if (page_was_allocated) + return ZSWAP_SWAPCACHE_NEW; + if (!*retpage) return ZSWAP_SWAPCACHE_FAIL; - *retpage = found_page; return ZSWAP_SWAPCACHE_EXIST; } |