diff options
Diffstat (limited to 'mm/swap_state.c')
| -rw-r--r-- | mm/swap_state.c | 57 |
1 files changed, 51 insertions, 6 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index e82f4f8b1f63..a29b33c7c236 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -110,12 +110,14 @@ void show_swap_cache_info(void) * add_to_swap_cache resembles add_to_page_cache_locked on swapper_space, * but sets SwapCache flag and private instead of mapping and index. */ -int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp) +int add_to_swap_cache(struct page *page, swp_entry_t entry, + gfp_t gfp, void **shadowp) { struct address_space *address_space = swap_address_space(entry); pgoff_t idx = swp_offset(entry); XA_STATE_ORDER(xas, &address_space->i_pages, idx, compound_order(page)); unsigned long i, nr = hpage_nr_pages(page); + void *old; VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(PageSwapCache(page), page); @@ -125,16 +127,25 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp) SetPageSwapCache(page); do { + unsigned long nr_shadows = 0; + xas_lock_irq(&xas); xas_create_range(&xas); if (xas_error(&xas)) goto unlock; for (i = 0; i < nr; i++) { VM_BUG_ON_PAGE(xas.xa_index != idx + i, page); + old = xas_load(&xas); + if (xa_is_value(old)) { + nr_shadows++; + if (shadowp) + *shadowp = old; + } set_page_private(page + i, entry.val + i); xas_store(&xas, page); xas_next(&xas); } + address_space->nrexceptional -= nr_shadows; address_space->nrpages += nr; __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr); ADD_CACHE_INFO(add_total, nr); @@ -154,7 +165,8 @@ unlock: * This must be called only on pages that have * been verified to be in the swap cache. */ -void __delete_from_swap_cache(struct page *page, swp_entry_t entry) +void __delete_from_swap_cache(struct page *page, + swp_entry_t entry, void *shadow) { struct address_space *address_space = swap_address_space(entry); int i, nr = hpage_nr_pages(page); @@ -166,12 +178,14 @@ void __delete_from_swap_cache(struct page *page, swp_entry_t entry) VM_BUG_ON_PAGE(PageWriteback(page), page); for (i = 0; i < nr; i++) { - void *entry = xas_store(&xas, NULL); + void *entry = xas_store(&xas, shadow); VM_BUG_ON_PAGE(entry != page, entry); set_page_private(page + i, 0); xas_next(&xas); } ClearPageSwapCache(page); + if (shadow) + address_space->nrexceptional += nr; address_space->nrpages -= nr; __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, -nr); ADD_CACHE_INFO(del_total, nr); @@ -208,7 +222,7 @@ int add_to_swap(struct page *page) * Add it to the swap cache. */ err = add_to_swap_cache(page, entry, - __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN); + __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN, NULL); if (err) /* * add_to_swap_cache() doesn't return -EEXIST, so we can safely @@ -246,13 +260,44 @@ void delete_from_swap_cache(struct page *page) struct address_space *address_space = swap_address_space(entry); xa_lock_irq(&address_space->i_pages); - __delete_from_swap_cache(page, entry); + __delete_from_swap_cache(page, entry, NULL); xa_unlock_irq(&address_space->i_pages); put_swap_page(page, entry); page_ref_sub(page, hpage_nr_pages(page)); } +void clear_shadow_from_swap_cache(int type, unsigned long begin, + unsigned long end) +{ + unsigned long curr = begin; + void *old; + + for (;;) { + unsigned long nr_shadows = 0; + swp_entry_t entry = swp_entry(type, curr); + struct address_space *address_space = swap_address_space(entry); + XA_STATE(xas, &address_space->i_pages, curr); + + xa_lock_irq(&address_space->i_pages); + xas_for_each(&xas, old, end) { + if (!xa_is_value(old)) + continue; + xas_store(&xas, NULL); + nr_shadows++; + } + address_space->nrexceptional -= nr_shadows; + xa_unlock_irq(&address_space->i_pages); + + /* search the next swapcache until we meet end */ + curr >>= SWAP_ADDRESS_SPACE_SHIFT; + curr++; + curr <<= SWAP_ADDRESS_SPACE_SHIFT; + if (curr > end) + break; + } +} + /* * If we are the only user, then try to free up the swap cache. * @@ -429,7 +474,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, __SetPageSwapBacked(page); /* May fail (-ENOMEM) if XArray node allocation failed. */ - if (add_to_swap_cache(page, entry, gfp_mask & GFP_RECLAIM_MASK)) { + if (add_to_swap_cache(page, entry, gfp_mask & GFP_RECLAIM_MASK, NULL)) { put_swap_page(page, entry); goto fail_unlock; } |