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From: David Rientjes <rientjes@google.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: 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, 7 Jun 2017 13:56:01 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.10.1706071352100.38905@chino.kir.corp.google.com> (raw)
In-Reply-To: <9ab81c3c-e064-66d2-6e82-fc9bac125f56@suse.cz>

On Wed, 7 Jun 2017, Vlastimil Babka wrote:

> >> Hmm I'd expect such spin lock to be reported together with mmap_sem in
> >> the debugging "locks held" message?
> > 
> > My bisection of the problem is about half done. My latest good version is commit 
> > 7b8cd33 and the latest bad one is 2ea659a. Only about 7 steps to go.
> 
> Hmm, your bisection will most likely just find commit 338a16ba15495
> which added the cond_resched() at mm/khugepaged.c:655. CCing David who
> added it.
> 

I agree it's probably going to bisect to 338a16ba15495 since it's the 
cond_resched() at the line number reported, but I think there must be 
something else going on.  I think the list of locks held by khugepaged is 
correct because it matches with the implementation.  The preempt_count(), 
as suggested by Andrew, does not.  If this is reproducible, I'd like to 
know what preempt_count() is.

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  reply	other threads:[~2017-06-07 20:56 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 [this message]
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
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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