From: Mel Gorman <mgorman@techsingularity.net>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
syzkaller <syzkaller@googlegroups.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: mm: deadlock between get_online_cpus/pcpu_alloc
Date: Tue, 7 Feb 2017 10:28:09 +0000 [thread overview]
Message-ID: <20170207102809.awh22urqmfrav5r6@techsingularity.net> (raw)
In-Reply-To: <2cdef192-1939-d692-1224-8ff7d7ff7203@suse.cz>
On Tue, Feb 07, 2017 at 10:49:28AM +0100, Vlastimil Babka wrote:
> On 02/07/2017 10:43 AM, Mel Gorman wrote:
> > If I'm reading this right, a hot-remove will set the pool POOL_DISASSOCIATED
> > and unbound. A workqueue queued for draining get migrated during hot-remove
> > and a drain operation will execute twice on a CPU -- one for what was
> > queued and a second time for the CPU it was migrated from. It should still
> > work with flush_work which doesn't appear to block forever if an item
> > got migrated to another workqueue. The actual drain workqueue function is
> > using the CPU ID it's currently running on so it shouldn't get confused.
>
> Is the worker that will process this migrated workqueue also guaranteed
> to be pinned to a cpu for the whole work, though? drain_local_pages()
> needs that guarantee.
>
It should be by running on a workqueue handler bound to that CPU (queued
on wq->cpu_pwqs in __queue_work)
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2017-02-07 10:28 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-29 12:44 mm: deadlock between get_online_cpus/pcpu_alloc Dmitry Vyukov
2017-01-29 17:22 ` Vlastimil Babka
2017-01-30 15:48 ` Dmitry Vyukov
2017-02-06 19:13 ` Dmitry Vyukov
2017-02-06 22:05 ` Mel Gorman
2017-02-07 8:48 ` Michal Hocko
2017-02-07 9:23 ` Vlastimil Babka
2017-02-07 9:46 ` Mel Gorman
2017-02-07 9:53 ` Michal Hocko
2017-02-07 10:42 ` Mel Gorman
2017-02-07 11:13 ` Mel Gorman
2017-02-07 9:43 ` Mel Gorman
2017-02-07 9:49 ` Vlastimil Babka
2017-02-07 10:05 ` Michal Hocko
2017-02-07 10:28 ` Mel Gorman [this message]
2017-02-07 10:35 ` Michal Hocko
2017-02-07 11:34 ` Mel Gorman
2017-02-07 11:43 ` Michal Hocko
2017-02-07 11:54 ` Vlastimil Babka
2017-02-07 12:08 ` Michal Hocko
2017-02-07 12:37 ` Michal Hocko
2017-02-07 12:43 ` Vlastimil Babka
2017-02-07 12:48 ` Michal Hocko
2017-02-07 13:57 ` Vlastimil Babka
2017-02-07 13:58 ` Mel Gorman
2017-02-07 14:19 ` Michal Hocko
2017-02-07 15:34 ` Michal Hocko
2017-02-07 16:22 ` Mel Gorman
2017-02-07 16:41 ` Michal Hocko
2017-02-07 16:55 ` Christoph Lameter
2017-02-07 22:25 ` Thomas Gleixner
2017-02-08 7:35 ` Michal Hocko
2017-02-08 12:02 ` Thomas Gleixner
2017-02-08 12:21 ` Michal Hocko
2017-02-08 12:26 ` Mel Gorman
2017-02-08 13:23 ` Thomas Gleixner
2017-02-08 14:03 ` Mel Gorman
2017-02-08 14:11 ` Peter Zijlstra
2017-02-08 15:11 ` Christoph Lameter
2017-02-08 15:21 ` Michal Hocko
2017-02-08 16:17 ` Christoph Lameter
2017-02-08 17:46 ` Thomas Gleixner
2017-02-09 3:15 ` Christoph Lameter
2017-02-09 11:42 ` Thomas Gleixner
2017-02-09 14:00 ` Christoph Lameter
2017-02-09 14:53 ` Thomas Gleixner
2017-02-09 15:42 ` Christoph Lameter
2017-02-09 16:12 ` Thomas Gleixner
2017-02-09 17:22 ` Christoph Lameter
2017-02-09 17:40 ` Thomas Gleixner
2017-02-09 19:15 ` Michal Hocko
2017-02-10 17:58 ` Christoph Lameter
2017-02-08 15:06 ` Christoph Lameter
2017-02-07 17:03 ` Tejun Heo
2017-02-07 20:16 ` Michal Hocko
2017-02-07 13:03 ` Mel Gorman
2017-02-07 13:48 ` Michal Hocko
2017-02-07 11:24 ` Tetsuo Handa
2017-02-07 8:43 ` Michal Hocko
2017-02-07 21:53 ` Thomas Gleixner
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