From: Michal Hocko <mhocko@suse.cz>
To: Andrew Morton <akpm@linux-foundation.org>,
"\\\"Rafael J. Wysocki\\\"" <rjw@rjwysocki.net>
Cc: Cong Wang <xiyou.wangcong@gmail.com>,
David Rientjes <rientjes@google.com>, Tejun Heo <tj@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: [PATCH 0/3] OOM vs. freezer interaction fixes
Date: Wed, 8 Oct 2014 16:07:43 +0200 [thread overview]
Message-ID: <1412777266-8251-1-git-send-email-mhocko@suse.cz> (raw)
Hi Andrew, Rafael,
this has been originally discussed here [1] but didn't lead anywhere AFAICS
so I would like to resurrect them.
The first and third patch are regression fixes and they are a stable
material IMO. The second patch is a simple cleanup.
The 1st patch is fixing a regression introduced in 3.3 since when OOM
killer is not able to kill any frozen task and live lock as a result.
The fix gets us back to the 3.2. As it turned out during the discussion [2]
this was still not 100% sufficient and that's why we need the 3rd patch.
I was thinking about the proper 1st vs. 3rd patch ordering because
the 1st patch basically opens a race window fixed by the later patch.
Original patch from Cong Wang has covered this by cgroup_freezing(current)
check in should_thaw_current(). But this approach still suffers from OOM
vs. PM freezer interaction (OOM killer would still live lock waiting for a
PM frozen task this time).
So I think the most straight forward way is to address only OOM vs.
frozen task interaction in the first patch, mark it for stable 3.3+ and
leave the race to a separate follow up patch which is applicable to
stable 3.2+ (before a3201227f803 made it inefficient).
Switching 1st and 3rd patches would make some sense as well but then
it might end up even more confusing because we would be fixing a
non-existent issue in upstream first...
---
[1] http://marc.info/?l=linux-kernel&m=140986986423092
[2] http://marc.info/?l=linux-kernel&m=141074263721166
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next reply other threads:[~2014-10-08 14:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-08 14:07 Michal Hocko [this message]
2014-10-08 14:07 ` [PATCH 1/3] freezer: check OOM kill while being frozen Michal Hocko
2014-10-08 14:07 ` [PATCH 2/3] freezer: remove obsolete comments in __thaw_task() Michal Hocko
2014-10-08 14:07 ` [PATCH 3/3] OOM, PM: OOM killed task cannot escape PM suspend Michal Hocko
2014-10-08 22:11 ` [PATCH 0/3] OOM vs. freezer interaction fixes Rafael J. Wysocki
2014-10-13 15:14 ` Michal Hocko
2014-10-09 4:42 ` Cong Wang
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