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From: Michal Hocko <mhocko@suse.cz>
To: "long.wanglong" <long.wanglong@huawei.com>
Cc: hannes@cmpxchg.org, shijie8@gmail.com,
torvalds@linux-foundation.org, azurit@pobox.sk,
hugh.dickins@tiscali.co.uk, rientjes@google.com,
kosaki.motohiro@jp.fujitsu.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
peifeiyue@huawei.com
Subject: Re: does the semantics of MAP_LOCKED is equal to mlock() function?
Date: Mon, 19 Jan 2015 12:01:16 +0100 [thread overview]
Message-ID: <20150119110116.GB21052@dhcp22.suse.cz> (raw)
In-Reply-To: <20150119094656.GA21052@dhcp22.suse.cz>
On Mon 19-01-15 10:46:56, Michal Hocko wrote:
[...]
> > testcase 2: mmap without MAP_LOCKED flag and the call mlock (memsize = 8192)
> >
> > 185 p = mmap(NULL, memsize, PROT_WRITE | PROT_READ,
> > 186 MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
> > 187 if (p == MAP_FAILED)
> > 188 err(1, "mmap(lock) failed");
> > 189
> > 190 if (mlock(p, memsize) == -1)
> > 191 err(1, "mlock failed")
> >
> > expect: invoke OOM killer.
> > result: invoke OOM killer.
Are you sure about this? memcg OOM killer shouldn't trigger even from
mlock path. It should just lead to ENOMEM. If you see the OOM killer
then it is probably coming from a page fault from a different source.
strace of your test would tell you more.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2015-01-19 11:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-19 6:17 long.wanglong
2015-01-19 9:46 ` Michal Hocko
2015-01-19 11:01 ` Michal Hocko [this message]
2015-01-20 3:23 ` long.wanglong
2015-01-20 12:58 ` Michal Hocko
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