From: Andrea Arcangeli <aarcange@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mel@csn.ul.ie>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/3] Fix migration races in rmap_walk() V2
Date: Wed, 28 Apr 2010 00:32:42 +0200 [thread overview]
Message-ID: <20100427223242.GG8860@random.random> (raw)
In-Reply-To: <alpine.DEB.2.00.1004271723090.24133@router.home>
On Tue, Apr 27, 2010 at 05:27:36PM -0500, Christoph Lameter wrote:
> Can we simply wait like in the fault path?
There is no bug there, no need to wait either. I already audited it
before, and I didn't see any bug. Unless you can show a bug with CPU A
running the rmap_walk on process1 before process2, there is no bug to
fix there.
>
> > Patch 3 notes that while a VMA is moved under the anon_vma lock, the page
> > tables are not similarly protected. Where migration PTEs are
> > encountered, they are cleaned up.
>
> This means they are copied / moved etc and "cleaned" up in a state when
> the page was unlocked. Migration entries are not supposed to exist when
> a page is not locked.
patch 3 is real, and the first thought I had was to lock down the page
before running vma_adjust and unlock after move_page_tables. But these
are virtual addresses. Maybe there's a simpler way to keep migration
away while we run those two operations.
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mel@csn.ul.ie>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Rik van Riel <riel@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/3] Fix migration races in rmap_walk() V2
Date: Wed, 28 Apr 2010 00:32:42 +0200 [thread overview]
Message-ID: <20100427223242.GG8860@random.random> (raw)
In-Reply-To: <alpine.DEB.2.00.1004271723090.24133@router.home>
On Tue, Apr 27, 2010 at 05:27:36PM -0500, Christoph Lameter wrote:
> Can we simply wait like in the fault path?
There is no bug there, no need to wait either. I already audited it
before, and I didn't see any bug. Unless you can show a bug with CPU A
running the rmap_walk on process1 before process2, there is no bug to
fix there.
>
> > Patch 3 notes that while a VMA is moved under the anon_vma lock, the page
> > tables are not similarly protected. Where migration PTEs are
> > encountered, they are cleaned up.
>
> This means they are copied / moved etc and "cleaned" up in a state when
> the page was unlocked. Migration entries are not supposed to exist when
> a page is not locked.
patch 3 is real, and the first thought I had was to lock down the page
before running vma_adjust and unlock after move_page_tables. But these
are virtual addresses. Maybe there's a simpler way to keep migration
away while we run those two operations.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-04-27 22:33 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-27 21:30 [PATCH 0/3] Fix migration races in rmap_walk() V2 Mel Gorman
2010-04-27 21:30 ` Mel Gorman
2010-04-27 21:30 ` [PATCH 1/3] mm,migration: During fork(), wait for migration to end if migration PTE is encountered Mel Gorman
2010-04-27 21:30 ` Mel Gorman
2010-04-27 22:22 ` Andrea Arcangeli
2010-04-27 22:22 ` Andrea Arcangeli
2010-04-27 23:52 ` KAMEZAWA Hiroyuki
2010-04-27 23:52 ` KAMEZAWA Hiroyuki
2010-04-28 0:18 ` Andrea Arcangeli
2010-04-28 0:18 ` Andrea Arcangeli
2010-04-28 0:19 ` Andrea Arcangeli
2010-04-28 0:19 ` Andrea Arcangeli
2010-04-28 0:28 ` KAMEZAWA Hiroyuki
2010-04-28 0:28 ` KAMEZAWA Hiroyuki
2010-04-28 0:59 ` Andrea Arcangeli
2010-04-28 0:59 ` Andrea Arcangeli
2010-04-28 8:24 ` Mel Gorman
2010-04-28 8:24 ` Mel Gorman
2010-04-27 21:30 ` [PATCH 2/3] mm,migration: Prevent rmap_walk_[anon|ksm] seeing the wrong VMA information Mel Gorman
2010-04-27 21:30 ` Mel Gorman
2010-04-27 23:10 ` Andrea Arcangeli
2010-04-27 23:10 ` Andrea Arcangeli
2010-04-28 9:15 ` Mel Gorman
2010-04-28 9:15 ` Mel Gorman
2010-04-28 15:35 ` Andrea Arcangeli
2010-04-28 15:35 ` Andrea Arcangeli
2010-04-28 15:39 ` Andrea Arcangeli
2010-04-28 15:39 ` Andrea Arcangeli
2010-04-28 15:55 ` Mel Gorman
2010-04-28 15:55 ` Mel Gorman
2010-04-28 16:23 ` Andrea Arcangeli
2010-04-28 16:23 ` Andrea Arcangeli
2010-04-28 17:34 ` Mel Gorman
2010-04-28 17:34 ` Mel Gorman
2010-04-28 17:58 ` Andrea Arcangeli
2010-04-28 17:58 ` Andrea Arcangeli
2010-04-28 17:47 ` [RFC PATCH] take all anon_vma locks in anon_vma_lock Rik van Riel
2010-04-28 17:47 ` Rik van Riel
2010-04-28 18:03 ` Andrea Arcangeli
2010-04-28 18:03 ` Andrea Arcangeli
2010-04-28 18:09 ` Rik van Riel
2010-04-28 18:09 ` Rik van Riel
2010-04-28 18:25 ` [RFC PATCH -v2] " Rik van Riel
2010-04-28 18:25 ` Rik van Riel
2010-04-28 19:07 ` Mel Gorman
2010-04-28 19:07 ` Mel Gorman
2010-04-28 20:17 ` [RFC PATCH -v3] " Rik van Riel
2010-04-28 20:17 ` Rik van Riel
2010-04-28 20:57 ` Rik van Riel
2010-04-28 20:57 ` Rik van Riel
2010-04-29 0:28 ` Minchan Kim
2010-04-29 0:28 ` Minchan Kim
2010-04-29 2:10 ` Rik van Riel
2010-04-29 2:10 ` Rik van Riel
2010-04-29 2:55 ` Minchan Kim
2010-04-29 2:55 ` Minchan Kim
2010-04-29 6:42 ` Minchan Kim
2010-04-29 6:42 ` Minchan Kim
2010-04-29 15:39 ` Rik van Riel
2010-04-29 15:39 ` Rik van Riel
2010-04-29 7:37 ` Mel Gorman
2010-04-29 7:37 ` Mel Gorman
2010-04-29 8:15 ` Mel Gorman
2010-04-29 8:15 ` Mel Gorman
2010-04-29 8:32 ` Minchan Kim
2010-04-29 8:32 ` Minchan Kim
2010-04-29 8:44 ` Mel Gorman
2010-04-29 8:44 ` Mel Gorman
2010-04-27 21:30 ` [PATCH 3/3] mm,migration: Remove straggling migration PTEs when page tables are being moved after the VMA has already moved Mel Gorman
2010-04-27 21:30 ` Mel Gorman
2010-04-27 22:30 ` Andrea Arcangeli
2010-04-27 22:30 ` Andrea Arcangeli
2010-04-27 22:58 ` Andrea Arcangeli
2010-04-27 22:58 ` Andrea Arcangeli
2010-04-28 0:39 ` KAMEZAWA Hiroyuki
2010-04-28 0:39 ` KAMEZAWA Hiroyuki
2010-04-28 1:05 ` Andrea Arcangeli
2010-04-28 1:05 ` Andrea Arcangeli
2010-04-28 1:09 ` Andrea Arcangeli
2010-04-28 1:09 ` Andrea Arcangeli
2010-04-28 1:18 ` KAMEZAWA Hiroyuki
2010-04-28 1:18 ` KAMEZAWA Hiroyuki
2010-04-28 1:36 ` Andrea Arcangeli
2010-04-28 1:36 ` Andrea Arcangeli
2010-04-28 1:29 ` KAMEZAWA Hiroyuki
2010-04-28 1:29 ` KAMEZAWA Hiroyuki
2010-04-28 1:44 ` Andrea Arcangeli
2010-04-28 1:44 ` Andrea Arcangeli
2010-04-28 2:12 ` KAMEZAWA Hiroyuki
2010-04-28 2:12 ` KAMEZAWA Hiroyuki
2010-04-28 2:42 ` Andrea Arcangeli
2010-04-28 2:42 ` Andrea Arcangeli
2010-04-28 2:49 ` KAMEZAWA Hiroyuki
2010-04-28 2:49 ` KAMEZAWA Hiroyuki
2010-04-28 7:28 ` KAMEZAWA Hiroyuki
2010-04-28 7:28 ` KAMEZAWA Hiroyuki
2010-04-28 10:48 ` Mel Gorman
2010-04-28 10:48 ` Mel Gorman
2010-04-28 0:03 ` KAMEZAWA Hiroyuki
2010-04-28 0:03 ` KAMEZAWA Hiroyuki
2010-04-28 0:08 ` Andrea Arcangeli
2010-04-28 0:08 ` Andrea Arcangeli
2010-04-28 0:36 ` KAMEZAWA Hiroyuki
2010-04-28 0:36 ` KAMEZAWA Hiroyuki
2010-04-28 8:30 ` KAMEZAWA Hiroyuki
2010-04-28 8:30 ` KAMEZAWA Hiroyuki
2010-04-28 14:46 ` Andrea Arcangeli
2010-04-28 14:46 ` Andrea Arcangeli
2010-04-27 22:27 ` [PATCH 0/3] Fix migration races in rmap_walk() V2 Christoph Lameter
2010-04-27 22:27 ` Christoph Lameter
2010-04-27 22:32 ` Andrea Arcangeli [this message]
2010-04-27 22:32 ` Andrea Arcangeli
2010-04-28 0:13 ` KAMEZAWA Hiroyuki
2010-04-28 0:13 ` KAMEZAWA Hiroyuki
2010-04-28 0:20 ` Andrea Arcangeli
2010-04-28 0:20 ` Andrea Arcangeli
2010-04-28 14:23 ` Mel Gorman
2010-04-28 14:23 ` Mel Gorman
2010-04-28 14:57 ` Mel Gorman
2010-04-28 14:57 ` Mel Gorman
2010-04-28 15:16 ` Andrea Arcangeli
2010-04-28 15:16 ` Andrea Arcangeli
2010-04-28 15:23 ` Mel Gorman
2010-04-28 15:23 ` Mel Gorman
2010-04-28 15:45 ` Andrea Arcangeli
2010-04-28 15:45 ` Andrea Arcangeli
2010-04-28 20:40 ` Andrea Arcangeli
2010-04-28 20:40 ` Andrea Arcangeli
2010-04-28 21:05 ` Andrea Arcangeli
2010-04-28 21:05 ` Andrea Arcangeli
2010-04-28 9:17 ` Mel Gorman
2010-04-28 9:17 ` Mel Gorman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100427223242.GG8860@random.random \
--to=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mel@csn.ul.ie \
--cc=minchan.kim@gmail.com \
--cc=riel@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.