From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, rientjes@google.com,
mjaggi@caviumnetworks.com, oleg@redhat.com,
vdavydov@virtuozzo.com
Subject: Re: [PATCH 2/2] mm,oom: Use ALLOC_OOM for OOM victim's last second allocation.
Date: Wed, 1 Nov 2017 16:16:00 +0100 [thread overview]
Message-ID: <20171101151600.olalzdipejtylkok@dhcp22.suse.cz> (raw)
In-Reply-To: <201711020008.EHB87824.QFFOJMLOHVFSOt@I-love.SAKURA.ne.jp>
On Thu 02-11-17 00:08:59, Tetsuo Handa wrote:
> Michal Hocko wrote:
[...]
> > I am not sure about this part though. If the oom_reaper cannot take the
> > mmap_sem then it retries for 1s. Have you ever seen the race to be that
> > large?
>
> Like shown in [2], khugepaged can prevent oom_reaper from taking the mmap_sem
> for 1 second. Also, it won't be impossible for OOM victims to spend 1 second
> between post __gfp_pfmemalloc_flags(gfp_mask) and pre mutex_trylock(&oom_lock)
> (in other words, the race window (1-2) above). Therefore, non artificial
> workloads could hit the same result.
but this is a speculation so I wouldn't mention it in the changelog. It
might confuse readers.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-11-01 15:16 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-01 11:54 [PATCH 1/2] mm,oom: Move last second allocation to inside the OOM killer Tetsuo Handa
2017-11-01 11:54 ` [PATCH 2/2] mm,oom: Use ALLOC_OOM for OOM victim's last second allocation Tetsuo Handa
2017-11-01 13:58 ` Michal Hocko
2017-11-01 15:08 ` Tetsuo Handa
2017-11-01 15:16 ` Michal Hocko [this message]
2017-11-01 13:27 ` [PATCH 1/2] mm,oom: Move last second allocation to inside the OOM killer Michal Hocko
2017-11-02 11:15 ` Tetsuo Handa
2017-11-02 11:16 ` [PATCH v2 " Tetsuo Handa
2017-11-02 11:16 ` [PATCH v2 2/2] mm,oom: Use ALLOC_OOM for OOM victim's last second allocation Tetsuo Handa
2017-11-02 13:14 ` Michal Hocko
2017-11-02 13:21 ` [PATCH v2 1/2] mm,oom: Move last second allocation to inside the OOM killer Michal Hocko
2017-11-03 13:46 ` [PATCH] mm,page_alloc: Update comment for last second allocation attempt Tetsuo Handa
2017-11-03 13:57 ` Michal Hocko
2017-11-03 14:08 ` Tetsuo Handa
2017-11-03 14:17 ` Michal Hocko
2017-11-03 14:27 ` Tetsuo Handa
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