From: David Rientjes <rientjes@google.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>,
Larry Finger <Larry.Finger@lwfinger.net>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: Sleeping BUG in khugepaged for i586
Date: Wed, 14 Jun 2017 17:28:16 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.10.1706141726200.105832@chino.kir.corp.google.com> (raw)
In-Reply-To: <20170612062918.GA4145@dhcp22.suse.cz>
On Mon, 12 Jun 2017, Michal Hocko wrote:
> > These are not soft lockups, these are need_resched warnings. We monitor
> > how long need_resched has been set and when a thread takes an excessive
> > amount of time to reschedule after it has been set. A loop of 512 pages
> > with ptl contention and doing {clear,copy}_user_highpage() shows that
> > need_resched can sit without scheduling for an excessive amount of time.
>
> How much is excessive here?
We monitor anything that holds the cpu for more than 1/20th of a second,
but this specific occurrence has been observed for ~1/8th. The majority
of mm/ is quite good in this regard.
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next prev parent reply other threads:[~2017-06-15 0:28 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-03 19:24 Larry Finger
2017-06-05 21:44 ` Andrew Morton
2017-06-06 14:02 ` Vlastimil Babka
2017-06-06 15:01 ` Larry Finger
2017-06-07 7:19 ` Vlastimil Babka
2017-06-07 20:56 ` David Rientjes
2017-06-08 14:48 ` Michal Hocko
2017-06-08 17:05 ` Matthew Wilcox
2017-06-08 20:18 ` Michal Hocko
2017-06-08 20:30 ` Michal Hocko
2017-06-09 6:48 ` Vlastimil Babka
2017-06-09 7:43 ` Michal Hocko
2017-06-09 14:28 ` Larry Finger
2017-06-09 22:38 ` David Rientjes
2017-06-10 8:09 ` Michal Hocko
2017-06-11 23:28 ` David Rientjes
2017-06-12 6:29 ` Michal Hocko
2017-06-15 0:28 ` David Rientjes [this message]
2017-06-15 1:12 ` David Rientjes
2017-06-15 8:32 ` Michal Hocko
2017-06-23 12:08 ` Michal Hocko
2017-06-23 13:13 ` Vlastimil Babka
2017-06-23 13:25 ` Michal Hocko
2017-06-23 15:28 ` Larry Finger
2017-06-08 15:29 ` Larry Finger
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