FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-21 08:53:41 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

mm: memcontrol: do not acquire page_cgroup lock for kmem pages

Browse Source 
Kmem page charging and uncharging is serialized by means of exclusive
access to the page.  Do not take the page_cgroup lock and don't set
pc->flags atomically.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2014-08-06 16:06:04 -07:00 committed by Linus Torvalds
parent 9a2385eef9
commit a840cda63e
1 changed files with 7 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
mm/memcontrol.c
View File

@ -3407,12 +3407,13 @@ void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
memcg_uncharge_kmem(memcg, PAGE_SIZE << order); memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
return; return;
} }
/*
* The page is freshly allocated and not visible to any
* outside callers yet. Set up pc non-atomically.
*/
pc = lookup_page_cgroup(page); pc = lookup_page_cgroup(page);
lock_page_cgroup(pc);
pc->mem_cgroup = memcg; pc->mem_cgroup = memcg;
SetPageCgroupUsed(pc); pc->flags = PCG_USED;
unlock_page_cgroup(pc);
} }
void __memcg_kmem_uncharge_pages(struct page *page, int order) void __memcg_kmem_uncharge_pages(struct page *page, int order)
@ -3422,19 +3423,11 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order)
pc = lookup_page_cgroup(page); pc = lookup_page_cgroup(page);
/*
* Fast unlocked return. Theoretically might have changed, have to
* check again after locking.
*/
if (!PageCgroupUsed(pc)) if (!PageCgroupUsed(pc))
return; return;
lock_page_cgroup(pc); memcg = pc->mem_cgroup;
if (PageCgroupUsed(pc)) { pc->flags = 0;
memcg = pc->mem_cgroup;
ClearPageCgroupUsed(pc);
}
unlock_page_cgroup(pc);
/* /*
* We trust that only if there is a memcg associated with the page, it * We trust that only if there is a memcg associated with the page, it