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authorJohannes Weiner <hannes@cmpxchg.org>2016-03-15 14:57:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-15 16:55:16 -0700
commitfdf1cdb91b6ab7a8a91df68c384f36b8a0909cab (patch)
tree828ad38946acad9990dcc733a10ebdeed0c1fbd5 /mm/vmscan.c
parent62cccb8c8e7a3ca233f49d5e7dcb1557d25465cd (diff)
downloadlinux-fdf1cdb91b6ab7a8a91df68c384f36b8a0909cab.tar.bz2
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 <hannes@cmpxchg.org> Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 34f7e2dae0a0..dd984470248f 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;
}