From: Rik van Riel <riel@redhat.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>,
Andrea Arcangeli <aarcange@redhat.com>,
Minchan Kim <minchan.kim@gmail.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 3/5] track the root (oldest) anon_vma
Date: Wed, 12 May 2010 22:25:15 -0400 [thread overview]
Message-ID: <4BEB630B.8070805@redhat.com> (raw)
In-Reply-To: <20100513093828.1cd022db.kamezawa.hiroyu@jp.fujitsu.com>
On 05/12/2010 08:38 PM, KAMEZAWA Hiroyuki wrote:
> On Wed, 12 May 2010 13:39:58 -0400
> Rik van Riel<riel@redhat.com> wrote:
>
>> Subject: track the root (oldest) anon_vma
>>
>> Track the root (oldest) anon_vma in each anon_vma tree. Because we only
>> take the lock on the root anon_vma, we cannot use the lock on higher-up
>> anon_vmas to lock anything. This makes it impossible to do an indirect
>> lookup of the root anon_vma, since the data structures could go away from
>> under us.
>>
>> However, a direct pointer is safe because the root anon_vma is always the
>> last one that gets freed on munmap or exit, by virtue of the same_vma list
>> order and unlink_anon_vmas walking the list forward.
>>
>> Signed-off-by: Rik van Riel<riel@redhat.com>
>
>
> Acked-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com>
>
> I welcome this. Thank you!
>
> Reading 4/5, I felt I'm grad if you add a Documentation or very-precise-comment
> about the new anon_vma rules and the _meaning_ of anon_vma_root_lock.
> I cannot fully convice myself that I understand them all.
Please send me a list of all the questions that come up
when you read the patches, and I'll prepare a patch 6/5
with just documentation :)
--
All rights reversed
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>,
Andrea Arcangeli <aarcange@redhat.com>,
Minchan Kim <minchan.kim@gmail.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 3/5] track the root (oldest) anon_vma
Date: Wed, 12 May 2010 22:25:15 -0400 [thread overview]
Message-ID: <4BEB630B.8070805@redhat.com> (raw)
In-Reply-To: <20100513093828.1cd022db.kamezawa.hiroyu@jp.fujitsu.com>
On 05/12/2010 08:38 PM, KAMEZAWA Hiroyuki wrote:
> On Wed, 12 May 2010 13:39:58 -0400
> Rik van Riel<riel@redhat.com> wrote:
>
>> Subject: track the root (oldest) anon_vma
>>
>> Track the root (oldest) anon_vma in each anon_vma tree. Because we only
>> take the lock on the root anon_vma, we cannot use the lock on higher-up
>> anon_vmas to lock anything. This makes it impossible to do an indirect
>> lookup of the root anon_vma, since the data structures could go away from
>> under us.
>>
>> However, a direct pointer is safe because the root anon_vma is always the
>> last one that gets freed on munmap or exit, by virtue of the same_vma list
>> order and unlink_anon_vmas walking the list forward.
>>
>> Signed-off-by: Rik van Riel<riel@redhat.com>
>
>
> Acked-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com>
>
> I welcome this. Thank you!
>
> Reading 4/5, I felt I'm grad if you add a Documentation or very-precise-comment
> about the new anon_vma rules and the _meaning_ of anon_vma_root_lock.
> I cannot fully convice myself that I understand them all.
Please send me a list of all the questions that come up
when you read the patches, and I'll prepare a patch 6/5
with just documentation :)
--
All rights reversed
--
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next prev parent reply other threads:[~2010-05-13 2:25 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-12 17:38 [PATCH 0/5] always lock the root anon_vma Rik van Riel
2010-05-12 17:38 ` Rik van Riel
2010-05-12 17:39 ` [PATCH 1/5] rename anon_vma_lock to vma_lock_anon_vma Rik van Riel
2010-05-12 17:39 ` Rik van Riel
2010-05-12 20:57 ` Mel Gorman
2010-05-12 20:57 ` Mel Gorman
2010-05-13 0:30 ` KAMEZAWA Hiroyuki
2010-05-13 0:30 ` KAMEZAWA Hiroyuki
2010-05-12 17:39 ` [PATCH 3/5] track the root (oldest) anon_vma Rik van Riel
2010-05-12 17:39 ` Rik van Riel
2010-05-12 20:59 ` Mel Gorman
2010-05-12 20:59 ` Mel Gorman
2010-05-12 21:01 ` Rik van Riel
2010-05-12 21:01 ` Rik van Riel
2010-05-13 0:38 ` KAMEZAWA Hiroyuki
2010-05-13 0:38 ` KAMEZAWA Hiroyuki
2010-05-13 2:25 ` Rik van Riel [this message]
2010-05-13 2:25 ` Rik van Riel
2010-05-14 0:04 ` KAMEZAWA Hiroyuki
2010-05-14 0:04 ` KAMEZAWA Hiroyuki
2010-05-12 17:40 ` [PATCH 4/5] always lock " Rik van Riel
2010-05-12 17:40 ` Rik van Riel
2010-05-12 21:02 ` Mel Gorman
2010-05-12 21:02 ` Mel Gorman
2010-05-12 21:08 ` Rik van Riel
2010-05-12 21:08 ` Rik van Riel
2010-05-13 9:54 ` Mel Gorman
2010-05-13 9:54 ` Mel Gorman
2010-05-13 14:33 ` [PATCH -v2 " Rik van Riel
2010-05-13 14:33 ` Rik van Riel
2010-05-13 21:09 ` Andrew Morton
2010-05-13 21:09 ` Andrew Morton
2010-05-13 22:50 ` Rik van Riel
2010-05-13 22:50 ` Rik van Riel
2010-05-14 9:33 ` Mel Gorman
2010-05-14 9:33 ` Mel Gorman
2010-05-26 4:00 ` Rik van Riel
2010-05-26 4:00 ` Rik van Riel
2010-05-26 4:15 ` Andrew Morton
2010-05-26 4:15 ` Andrew Morton
2010-05-26 5:46 ` james toy
2010-05-26 5:46 ` james toy
2010-06-01 0:57 ` james toy
2010-06-01 0:57 ` james toy
2010-05-26 15:24 ` [PATCH -v2 0/5] always lock the root anon_vma Rik van Riel
2010-05-26 15:24 ` Rik van Riel
2010-05-26 15:25 ` [PATCH 1/5] rename anon_vma_lock to vma_lock_anon_vma Rik van Riel
2010-05-26 15:25 ` Rik van Riel
2010-05-26 17:25 ` Linus Torvalds
2010-05-26 17:25 ` Linus Torvalds
2010-05-26 19:01 ` Rik van Riel
2010-05-26 19:01 ` Rik van Riel
2010-05-26 19:25 ` Linus Torvalds
2010-05-26 19:25 ` Linus Torvalds
2010-05-26 19:35 ` Rik van Riel
2010-05-26 19:35 ` Rik van Riel
2010-05-26 15:25 ` [PATCH 2/5] change direct call of spin_lock(anon_vma->lock) to inline function Rik van Riel
2010-05-26 15:25 ` Rik van Riel
2010-05-26 15:26 ` [PATCH 3/5] track the root (oldest) anon_vma Rik van Riel
2010-05-26 15:26 ` Rik van Riel
2010-05-26 15:27 ` [PATCH 4/5] always lock " Rik van Riel
2010-05-26 15:27 ` Rik van Riel
2010-05-26 15:27 ` [PATCH 5/5] extend KSM refcounts to the anon_vma root Rik van Riel
2010-05-26 15:27 ` Rik van Riel
2010-05-12 21:55 ` [PATCH 4/5] always lock the root (oldest) anon_vma Linus Torvalds
2010-05-12 21:55 ` Linus Torvalds
2010-05-12 22:18 ` Rik van Riel
2010-05-12 22:18 ` Rik van Riel
2010-05-12 22:26 ` Linus Torvalds
2010-05-12 22:26 ` Linus Torvalds
2010-05-12 17:41 ` [PATCH 5/5] extend KSM refcounts to the anon_vma root Rik van Riel
2010-05-12 17:41 ` Rik van Riel
2010-05-12 21:07 ` Mel Gorman
2010-05-12 21:07 ` Mel Gorman
2010-05-12 21:09 ` Rik van Riel
2010-05-12 21:09 ` Rik van Riel
2010-05-13 11:26 ` Mel Gorman
2010-05-13 11:26 ` Mel Gorman
2010-05-13 13:11 ` Rik van Riel
2010-05-13 13:11 ` Rik van Riel
2010-05-13 13:24 ` Mel Gorman
2010-05-13 13:24 ` Mel Gorman
2010-05-13 14:34 ` [PATCH -v2 " Rik van Riel
2010-05-13 14:34 ` Rik van Riel
2010-05-19 1:05 ` Andrea Arcangeli
2010-05-19 1:05 ` Andrea Arcangeli
2010-05-12 17:41 ` [PATCH 2/5] change direct call of spin_lock(anon_vma->lock) to inline function Rik van Riel
2010-05-12 17:41 ` Rik van Riel
2010-05-12 20:58 ` Mel Gorman
2010-05-12 20:58 ` Mel Gorman
2010-05-13 0:32 ` KAMEZAWA Hiroyuki
2010-05-13 0:32 ` KAMEZAWA Hiroyuki
2010-05-20 22:42 ` [PATCH 6/5] adjust mm_take_all_locks to anon-vma-root locking Andrea Arcangeli
2010-05-20 22:42 ` Andrea Arcangeli
2010-05-20 23:07 ` Rik van Riel
2010-05-20 23:07 ` Rik van Riel
-- strict thread matches above, loose matches on Subject: below --
2010-05-26 19:38 [PATCH -v3 0/5] always lock the root anon_vma Rik van Riel
2010-05-26 19:40 ` [PATCH 3/5] track the root (oldest) anon_vma Rik van Riel
2010-05-26 19:40 ` Rik van Riel
2010-05-26 20:34 ` Larry Woodman
2010-05-26 20:34 ` Larry Woodman
2010-05-27 13:48 ` Minchan Kim
2010-05-27 13:48 ` Minchan Kim
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