From fdf1cdb91b6ab7a8a91df68c384f36b8a0909cab Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Tue, 15 Mar 2016 14:57:25 -0700 Subject: mm: remove unnecessary uses of lock_page_memcg() There are several users that nest lock_page_memcg() inside lock_page() to prevent page->mem_cgroup from changing. But the page lock prevents pages from moving between cgroups, so that is unnecessary overhead. Remove lock_page_memcg() in contexts with locked contexts and fix the debug code in the page stat functions to be okay with the page lock. Signed-off-by: Johannes Weiner Acked-by: Vladimir Davydov Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 7 +------ mm/page-writeback.c | 2 -- mm/truncate.c | 3 --- mm/vmscan.c | 4 ---- 4 files changed, 1 insertion(+), 15 deletions(-) (limited to 'mm') diff --git a/mm/filemap.c b/mm/filemap.c index 8e629c4..61b441b 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -176,8 +176,7 @@ static void page_cache_tree_delete(struct address_space *mapping, /* * Delete a page from the page cache and free it. Caller has to make * sure the page is locked and that nobody else uses it - or that usage - * is safe. The caller must hold the mapping's tree_lock and - * lock_page_memcg(). + * is safe. The caller must hold the mapping's tree_lock. */ void __delete_from_page_cache(struct page *page, void *shadow) { @@ -260,11 +259,9 @@ void delete_from_page_cache(struct page *page) freepage = mapping->a_ops->freepage; - lock_page_memcg(page); spin_lock_irqsave(&mapping->tree_lock, flags); __delete_from_page_cache(page, NULL); spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(page); if (freepage) freepage(page); @@ -557,7 +554,6 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) new->mapping = mapping; new->index = offset; - lock_page_memcg(old); spin_lock_irqsave(&mapping->tree_lock, flags); __delete_from_page_cache(old, NULL); error = radix_tree_insert(&mapping->page_tree, offset, new); @@ -572,7 +568,6 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) if (PageSwapBacked(new)) __inc_zone_page_state(new, NR_SHMEM); spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(old); mem_cgroup_migrate(old, new); radix_tree_preload_end(); if (freepage) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d7cf2c5..11ff8f7 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2700,7 +2700,6 @@ int clear_page_dirty_for_io(struct page *page) * always locked coming in here, so we get the desired * exclusion. */ - lock_page_memcg(page); wb = unlocked_inode_to_wb_begin(inode, &locked); if (TestClearPageDirty(page)) { mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_DIRTY); @@ -2709,7 +2708,6 @@ int clear_page_dirty_for_io(struct page *page) ret = 1; } unlocked_inode_to_wb_end(inode, locked); - unlock_page_memcg(page); return ret; } return TestClearPageDirty(page); diff --git a/mm/truncate.c b/mm/truncate.c index 87311af..7598b55 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -527,7 +527,6 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return 0; - lock_page_memcg(page); spin_lock_irqsave(&mapping->tree_lock, flags); if (PageDirty(page)) goto failed; @@ -535,7 +534,6 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) BUG_ON(page_has_private(page)); __delete_from_page_cache(page, NULL); spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(page); if (mapping->a_ops->freepage) mapping->a_ops->freepage(page); @@ -544,7 +542,6 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) return 1; failed: spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(page); return 0; } diff --git a/mm/vmscan.c b/mm/vmscan.c index 34f7e2d..dd98447 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -607,7 +607,6 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, BUG_ON(!PageLocked(page)); BUG_ON(mapping != page_mapping(page)); - lock_page_memcg(page); spin_lock_irqsave(&mapping->tree_lock, flags); /* * The non racy check for a busy page. @@ -647,7 +646,6 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, mem_cgroup_swapout(page, swap); __delete_from_swap_cache(page); spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(page); swapcache_free(swap); } else { void (*freepage)(struct page *); @@ -675,7 +673,6 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, shadow = workingset_eviction(mapping, page); __delete_from_page_cache(page, shadow); spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(page); if (freepage != NULL) freepage(page); @@ -685,7 +682,6 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, cannot_free: spin_unlock_irqrestore(&mapping->tree_lock, flags); - unlock_page_memcg(page); return 0; } -- cgit v1.1