From: Linus Torvalds <torvalds@linux-foundation.org>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andi Kleen <ak@linux.intel.com>,
Shaohua Li <shaohua.li@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
David Miller <davem@davemloft.net>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Russell King <rmk@arm.linux.org.uk>,
Paul Mundt <lethal@linux-sh.org>, Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
"Luck, Tony" <tony.luck@intel.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Mel Gorman <mel@csn.ul.ie>, Nick Piggin <npiggin@kernel.dk>,
Namhyung Kim <namhyung@gmail.com>,
"Shi, Alex" <alex.shi@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: REGRESSION: Performance regressions from switching anon_vma->lock to mutex
Date: Thu, 16 Jun 2011 14:26:41 -0700 [thread overview]
Message-ID: <BANLkTimLV8aCZ7snXT_Do+f4vRY0EkoS4A@mail.gmail.com> (raw)
In-Reply-To: <BANLkTim-dBjva9w7AajqggKT3iUVYG2euQ@mail.gmail.com>
On Thu, Jun 16, 2011 at 2:06 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Thu, Jun 16, 2011 at 2:05 PM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> This patch is UNTESTED!
>
> It was also UNATTACHED!
Hmm. And it doesn't work. We deadlock when we free the anon_vma
because the *freeing* path wants to take the anon_vma lock. See that
horrid code in anon_vma_free().
So now we now hold the root over the whole series of frees, and get an
instant deadlock.
We also can happen to free the root anon_vma before we release the
lock in it, which is another slight problem ;)
So the unlink_anon_vmas() case is actually much more complicated than
the clone case.
In other words, just forget that second patch. I'll have to think about it.
Linus
next prev parent reply other threads:[~2011-06-16 21:33 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-15 0:29 Tim Chen
2011-06-15 0:36 ` Andi Kleen
2011-06-17 19:07 ` Ingo Molnar
2011-06-15 1:21 ` Linus Torvalds
2011-06-15 3:42 ` Linus Torvalds
2011-06-15 1:26 ` Shaohua Li
2011-06-15 11:52 ` Peter Zijlstra
2011-06-15 12:49 ` Peter Zijlstra
2011-06-15 16:18 ` Andi Kleen
2011-06-15 16:45 ` Peter Zijlstra
2011-06-15 16:47 ` Andi Kleen
2011-06-15 18:43 ` Tim Chen
2011-06-15 20:32 ` Peter Zijlstra
2011-06-15 20:57 ` Andi Kleen
2011-06-15 21:12 ` Tim Chen
2011-06-15 21:37 ` Peter Zijlstra
2011-06-15 21:51 ` Linus Torvalds
2011-06-15 22:19 ` Andi Kleen
2011-06-16 0:16 ` Linus Torvalds
2011-06-16 20:14 ` Andi Kleen
2011-06-16 20:37 ` Linus Torvalds
2011-06-17 0:24 ` Andi Kleen
2011-06-17 9:13 ` Ingo Molnar
2011-06-15 22:15 ` Andi Kleen
2011-06-16 1:08 ` Tim Chen
2011-06-16 1:50 ` Linus Torvalds
2011-06-16 20:26 ` Tim Chen
2011-06-16 20:47 ` Linus Torvalds
2011-06-16 21:05 ` Linus Torvalds
2011-06-16 21:06 ` Linus Torvalds
2011-06-16 21:26 ` Linus Torvalds [this message]
2011-06-17 3:58 ` Linus Torvalds
2011-06-17 11:28 ` Peter Zijlstra
2011-06-17 11:54 ` Peter Zijlstra
2011-06-17 16:36 ` Linus Torvalds
2011-06-17 17:41 ` Hugh Dickins
2011-06-17 17:55 ` Peter Zijlstra
2011-06-17 18:01 ` Linus Torvalds
2011-06-17 18:18 ` Peter Zijlstra
2011-06-17 18:32 ` Peter Zijlstra
2011-06-17 18:39 ` Linus Torvalds
2011-06-17 18:41 ` Linus Torvalds
2011-06-17 20:19 ` Tim Chen
2011-06-17 22:20 ` Hugh Dickins
2011-06-18 4:47 ` Linus Torvalds
2011-06-17 19:53 ` [PATCH] mm, memory-failure: Fix spinlock vs mutex order Peter Zijlstra
2011-06-17 20:04 ` Andi Kleen
2011-06-17 16:46 ` REGRESSION: Performance regressions from switching anon_vma->lock to mutex Linus Torvalds
2011-06-17 17:28 ` Linus Torvalds
2011-06-17 19:40 ` Andi Kleen
2011-06-18 8:08 ` Ingo Molnar
2011-06-17 18:22 ` Tim Chen
2011-06-17 19:05 ` Ray Lee
2011-06-16 22:00 ` Andi Kleen
2011-06-15 10:36 ` Peter Zijlstra
2011-06-15 10:58 ` Peter Zijlstra
2011-06-15 11:41 ` Peter Zijlstra
2011-06-15 19:11 ` Linus Torvalds
2011-06-15 19:24 ` Andrew Morton
2011-06-15 20:16 ` Ingo Molnar
2011-06-15 20:55 ` Linus Torvalds
2011-06-15 20:12 ` [GIT PULL] " Ingo Molnar
2011-06-15 20:29 ` Paul E. McKenney
2011-06-15 20:47 ` Linus Torvalds
2011-06-15 20:54 ` Paul E. McKenney
2011-06-15 21:05 ` Linus Torvalds
2011-06-15 21:15 ` Paul E. McKenney
2011-06-15 21:27 ` Linus Torvalds
2011-06-16 7:03 ` Ingo Molnar
2011-06-16 17:16 ` Paul E. McKenney
2011-06-16 20:25 ` Ingo Molnar
2011-06-16 21:01 ` Frederic Weisbecker
2011-06-16 23:02 ` Ingo Molnar
2011-06-17 15:19 ` Frederic Weisbecker
2011-06-16 21:02 ` Andi Kleen
2011-06-16 22:21 ` Benjamin Herrenschmidt
2011-06-16 22:38 ` Ingo Molnar
2011-06-16 22:47 ` Andi Kleen
2011-06-16 22:58 ` Ingo Molnar
2011-06-17 0:45 ` Paul E. McKenney
2011-06-17 9:43 ` Ingo Molnar
2011-06-17 16:48 ` Paul E. McKenney
2011-06-16 23:37 ` Paul E. McKenney
2011-06-15 20:13 ` Tim Chen
2011-06-15 20:17 ` Ingo Molnar
2011-06-15 20:21 ` Tim Chen
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