From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: linux-mm@kvack.org
Subject: Re: mm: Can we bail out p?d_alloc() loops upon SIGKILL?
Date: Wed, 27 Feb 2019 10:21:36 +0100 [thread overview]
Message-ID: <20190227092136.GM10588@dhcp22.suse.cz> (raw)
In-Reply-To: <201902270343.x1R3hpZl029621@www262.sakura.ne.jp>
On Wed 27-02-19 12:43:51, Tetsuo Handa wrote:
> I noticed that when a kdump kernel triggers the OOM killer because a too
> small value was given to crashkernel= parameter, the OOM reaper tends to
> fail to reclaim memory from OOM victims because they are in dup_mm() from
> copy_mm() from copy_process() with mmap_sem held for write.
I would presume that a page table allocation would fail for the oom
victim as soon as the oom memory reserves get depleted and then
copy_page_range would bail out and release the lock. That being
said, the oom_reaper might bail out before then but does sprinkling
fatal_signal_pending checks into copy_*_range really help reliably?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-02-27 9:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 3:43 mm: Can we bail out p?d_alloc() loops upon SIGKILL? Tetsuo Handa
2019-02-27 9:21 ` Michal Hocko [this message]
2019-02-27 10:39 ` Tetsuo Handa
2019-02-28 9:26 ` Michal Hocko
2019-03-01 10:30 ` Tetsuo Handa
2019-03-01 11:49 ` Michal Hocko
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