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From: Dave Jones <davej@redhat.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Rik van Riel <riel@redhat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Hillf Danton <dhillf@gmail.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] hugetlb: fix lockdep splat caused by pmd sharing
Date: Tue, 30 Jul 2013 19:37:23 -0400	[thread overview]
Message-ID: <20130730233722.GA28747@redhat.com> (raw)
In-Reply-To: <20130730233530.GA19340@bbox>

On Wed, Jul 31, 2013 at 08:35:30AM +0900, Minchan Kim wrote:
 > > which is a false positive caused by hugetlb pmd sharing code which
 > > allocates a new pmd from withing mappint->i_mmap_mutex. If this
 > > allocation causes reclaim then the lockdep detector complains that we
 > > might self-deadlock.
 > > 
 > > This is not correct though, because hugetlb pages are not reclaimable so
 > > their mapping will be never touched from the reclaim path.
 > > 
 > > The patch tells lockup detector that hugetlb i_mmap_mutex is special
 > > by assigning it a separate lockdep class so it won't report possible
 > > deadlocks on unrelated mappings.
 > > 
 > > [peterz@infradead.org: comment for annotation]
 > > Reported-by: Dave Jones <davej@redhat.com>
 > > Signed-off-by: Michal Hocko <mhocko@suse.cz>
 > Reviewed-by: Minchan Kim <minchan@kernel.org>
 > 
 > Thanks, Michal!
 > Only remained thing is Dave's testing.

I've added it to my builds, all is quiet so far..

	Dave





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  reply	other threads:[~2013-07-30 23:38 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-17 15:32 hugepage related lockdep trace Dave Jones
2013-07-18  0:09 ` Minchan Kim
2013-07-18 17:42   ` Aneesh Kumar K.V
2013-07-19  0:13     ` Minchan Kim
2013-07-23  7:24       ` Hush Bensen
2013-07-24  2:57         ` Minchan Kim
2013-07-23 14:01       ` Michal Hocko
2013-07-24  2:44         ` Minchan Kim
2013-07-25 13:30           ` Michal Hocko
2013-07-29  8:24             ` Minchan Kim
2013-07-29 14:53               ` Michal Hocko
2013-07-29 15:20                 ` Peter Zijlstra
2013-07-30 14:29                   ` Michal Hocko
2013-07-30 14:46                     ` [PATCH] hugetlb: fix lockdep splat caused by pmd sharing Michal Hocko
2013-07-30 14:58                       ` Peter Zijlstra
2013-07-30 15:23                         ` Michal Hocko
2013-07-30 23:35                           ` Minchan Kim
2013-07-30 23:37                             ` Dave Jones [this message]
2013-07-19  2:08     ` hugepage related lockdep trace Hillf Danton
2013-07-19  3:20       ` Aneesh Kumar K.V

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