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From: Michal Hocko <mhocko@kernel.org>
To: Daniel Jordan <daniel.m.jordan@oracle.com>,
	Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>,
	Shile Zhang <shile.zhang@linux.alibaba.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm: fix tick timer stall during deferred page init
Date: Wed, 1 Apr 2020 18:26:55 +0200	[thread overview]
Message-ID: <20200401162655.GX22681@dhcp22.suse.cz> (raw)
In-Reply-To: <20200401161810.xvqikca2x46yqrlx@ca-dmjordan1.us.oracle.com>

On Wed 01-04-20 12:18:10, Daniel Jordan wrote:
> On Wed, Apr 01, 2020 at 06:12:43PM +0200, Michal Hocko wrote:
> > On Wed 01-04-20 12:09:29, Daniel Jordan wrote:
> > > On Wed, Apr 01, 2020 at 06:00:48PM +0200, Michal Hocko wrote:
> > > > On Wed 01-04-20 17:50:22, David Hildenbrand wrote:
> > > > > On 01.04.20 17:42, Michal Hocko wrote:
> > > > > > This needs a double checking but I strongly believe that the lock can be
> > > > > > simply dropped in this path.
> > > 
> > > This is what my fix does, it limits the time the resize lock is held.
> > 
> > Just remove it from the deferred intialization and add a comment that we
> > deliberately not taking the lock here because abc
> 
> I think it has to be a little more involved because of the window where
> interrupts might allocate during deferred init, as Vlastimil pointed out a few
> years ago when the change was made.

I do not remember any details but do we have any actual real allocation
failure or was this mostly a theoretical concern. Vlastimil? For your
context we are talking about 3a2d7fa8a3d5 ("mm: disable interrupts while
initializing deferred pages")

> I'll explain myself in the changelog.

OK, I will wait for the patch.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2020-04-01 16:27 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 12:38 Shile Zhang
2020-03-11 17:45 ` Pavel Tatashin
2020-03-11 20:16   ` Kirill Tkhai
2020-03-11 20:25     ` Pavel Tatashin
2020-03-19 19:05 ` Daniel Jordan
2020-03-26 18:58   ` Daniel Jordan
2020-03-26 19:36     ` Pavel Tatashin
2020-03-27  4:39       ` Shile Zhang
2020-03-28  0:17         ` Daniel Jordan
2020-04-01 14:26 ` David Hildenbrand
2020-04-01 15:42 ` Michal Hocko
2020-04-01 15:50   ` David Hildenbrand
2020-04-01 16:00     ` Michal Hocko
2020-04-01 16:09       ` Daniel Jordan
2020-04-01 16:12         ` Michal Hocko
2020-04-01 16:15           ` David Hildenbrand
2020-04-01 16:18           ` Daniel Jordan
2020-04-01 16:26             ` Michal Hocko [this message]
2020-04-01 16:41               ` Pavel Tatashin
2020-04-01 16:46                 ` Michal Hocko
2020-04-01 16:51                   ` Pavel Tatashin
2020-04-01 17:13                     ` Daniel Jordan

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