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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Roman Gushchin <guro@fb.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch v2] mm, oom: fix concurrent munlock and oom reaper unmap
Date: Wed, 18 Apr 2018 12:55:22 +0900	[thread overview]
Message-ID: <201804180355.w3I3tM6T001187@www262.sakura.ne.jp> (raw)
In-Reply-To: <alpine.DEB.2.21.1804171951440.105401@chino.kir.corp.google.com>

David Rientjes wrote:
> Fix this by reusing MMF_UNSTABLE to specify that an mm should not be
> reaped.  This prevents the concurrent munlock_vma_pages_range() and
> unmap_page_range().  The oom reaper will simply not operate on an mm that
> has the bit set and leave the unmapping to exit_mmap().

This change assumes that munlock_vma_pages_all()/unmap_vmas()/free_pgtables()
are never blocked for memory allocation. Is that guaranteed? For example,
i_mmap_lock_write() from unmap_single_vma() from unmap_vmas() is never blocked
for memory allocation? Commit 97b1255cb27c551d ("mm,oom_reaper: check for
MMF_OOM_SKIP before complaining") was waiting for i_mmap_lock_write() from
unlink_file_vma() from free_pgtables(). Is it really guaranteed that somebody
else who is holding that lock is never waiting for memory allocation?

  reply	other threads:[~2018-04-18  3:55 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17 22:46 [patch] " David Rientjes
2018-04-18  0:57 ` Tetsuo Handa
2018-04-18  2:39   ` David Rientjes
2018-04-18  2:52     ` [patch v2] " David Rientjes
2018-04-18  3:55       ` Tetsuo Handa [this message]
2018-04-18  4:11         ` David Rientjes
2018-04-18  4:47           ` Tetsuo Handa
2018-04-18  5:20             ` David Rientjes
2018-04-18  7:50       ` Michal Hocko
2018-04-18 11:49         ` Tetsuo Handa
2018-04-18 11:58           ` Michal Hocko
2018-04-18 13:25             ` Tetsuo Handa
2018-04-18 13:44               ` Michal Hocko
2018-04-18 14:28                 ` Tetsuo Handa
2018-04-18 19:14         ` David Rientjes
2018-04-19  6:35           ` Michal Hocko
2018-04-19 10:45             ` Tetsuo Handa
2018-04-19 11:04               ` Michal Hocko
2018-04-19 11:51                 ` Tetsuo Handa
2018-04-19 12:48                   ` Michal Hocko
2018-04-19 19:14               ` David Rientjes
2018-04-19 19:34             ` David Rientjes
2018-04-19 22:13               ` Tetsuo Handa
2018-04-20  8:23               ` Michal Hocko
2018-04-20 12:40                 ` Michal Hocko
2018-04-22  3:22                   ` David Rientjes
2018-04-22  3:48                     ` [patch v2] mm, oom: fix concurrent munlock and oom reaperunmap Tetsuo Handa
2018-04-22 13:08                       ` Michal Hocko
2018-04-24  2:31                       ` David Rientjes
2018-04-24  5:11                         ` Tetsuo Handa
2018-04-24  5:35                           ` David Rientjes
2018-04-24 21:57                             ` [patch v2] mm, oom: fix concurrent munlock and oom reaper unmap Tetsuo Handa
2018-04-24 22:25                               ` David Rientjes
2018-04-24 22:34                                 ` [patch v3 for-4.17] " David Rientjes
2018-04-24 23:19                                   ` Michal Hocko
2018-04-24 13:04                         ` [patch v2] mm, oom: fix concurrent munlock and oom reaperunmap Michal Hocko
2018-04-24 20:01                           ` David Rientjes
2018-04-24 20:13                             ` Michal Hocko
2018-04-24 20:22                               ` David Rientjes
2018-04-24 20:31                                 ` Michal Hocko
2018-04-24 21:07                                   ` David Rientjes
2018-04-24 23:08                                     ` Michal Hocko
2018-04-24 23:14                                       ` Michal Hocko
2018-04-22  3:45                 ` [patch v2] mm, oom: fix concurrent munlock and oom reaper unmap David Rientjes
2018-04-22 13:18                   ` Michal Hocko
2018-04-23 16:09                     ` Michal Hocko

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