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From: Michal Hocko <mhocko@suse.cz>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Vladimir Davydov <vdavydov@parallels.com>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [patch] mm: memcontrol: micro-optimize mem_cgroup_update_page_stat()
Date: Mon, 20 Oct 2014 20:59:44 +0200	[thread overview]
Message-ID: <20141020185944.GC505@dhcp22.suse.cz> (raw)
In-Reply-To: <1413818259-10913-1-git-send-email-hannes@cmpxchg.org>

On Mon 20-10-14 11:17:39, Johannes Weiner wrote:
> Do not look up the page_cgroup when the memory controller is
> runtime-disabled, but do assert that the locking protocol is followed
> under DEBUG_VM regardless.  Also remove the unused flags variable.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Michal Hocko <mhocko@suse.cz>

mem_cgroup_split_huge_fixup is following the same pattern and might be
folded into this one. I can send a separate patch if you prefer, though.
---
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3a203c7ec6c7..544e32292c7f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3167,7 +3167,7 @@ static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
 {
-	struct page_cgroup *head_pc = lookup_page_cgroup(head);
+	struct page_cgroup *head_pc;
 	struct page_cgroup *pc;
 	struct mem_cgroup *memcg;
 	int i;
@@ -3175,6 +3175,8 @@ void mem_cgroup_split_huge_fixup(struct page *head)
 	if (mem_cgroup_disabled())
 		return;
 
+	head_pc = lookup_page_cgroup(head);
+
 	memcg = head_pc->mem_cgroup;
 	for (i = 1; i < HPAGE_PMD_NR; i++) {
 		pc = head_pc + i;
-- 
Michal Hocko
SUSE Labs

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      reply	other threads:[~2014-10-20 18:59 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-20 15:17 [patch] mm: memcontrol: micro-optimize mem_cgroup_update_page_stat() Johannes Weiner
2014-10-20 18:59 ` Michal Hocko [this message]

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