From: Johannes Weiner <hannes@cmpxchg.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [patch rfc] memcg: remove NULL check from lookup_page_cgroup() result
Date: Thu, 3 Feb 2011 15:12:30 +0100 [thread overview]
Message-ID: <20110203141230.GG2286@cmpxchg.org> (raw)
The page_cgroup array is set up before even fork is initialized. I
seriously doubt that this code executes before the array is alloc'd.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
mm/memcontrol.c | 5 +----
1 files changed, 1 insertions(+), 4 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a145c9e..6abaa10 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2343,10 +2343,7 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
}
pc = lookup_page_cgroup(page);
- /* can happen at boot */
- if (unlikely(!pc))
- return 0;
- prefetchw(pc);
+ BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */
ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, oom, page_size);
if (ret || !mem)
--
1.7.4
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next reply other threads:[~2011-02-03 14:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-03 14:12 Johannes Weiner [this message]
2011-02-03 23:59 ` KAMEZAWA Hiroyuki
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