From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org, Martin Schwidefsky <schwidefsky@de.ibm.com>,
Mel Gorman <mgorman@suse.de>,
linux-s390@vger.kernel.org, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] mm: Fix XFS oops due to dirty pages without buffers on s390
Date: Tue, 23 Oct 2012 14:56:36 -0700 [thread overview]
Message-ID: <20121023145636.0a9b9a3e.akpm@linux-foundation.org> (raw)
In-Reply-To: <20121023102153.GD3064@quack.suse.cz>
On Tue, 23 Oct 2012 12:21:53 +0200
Jan Kara <jack@suse.cz> wrote:
> > That seems a fairly serious problem. To which kernel version(s) should
> > we apply the fix?
> Well, XFS will crash starting from 2.6.36 kernel where the assertion was
> added. Previously XFS just silently added buffers (as other filesystems do
> it) and wrote / redirtied the page (unnecessarily). So looking into
> maintained -stable branches I think pushing the patch to -stable from 3.0
> on should be enough.
OK, thanks, I made it so.
> > > diff --git a/mm/rmap.c b/mm/rmap.c
> >
> > It's a bit surprising that none of the added comments mention the s390
> > pte-dirtying oddity. I don't see an obvious place to mention this, but
> > I for one didn't know about this and it would be good if we could
> > capture the info _somewhere_?
> As Hugh says, the comment before page_test_and_clear_dirty() is somewhat
> updated. But do you mean recording somewhere the catch that s390 HW dirty
> bit gets set also whenever we write to a page from kernel?
Yes, this. It's surprising behaviour which we may trip over again, so
how do we inform developers about it?
> I guess we could
> add that also to the comment before page_test_and_clear_dirty() in
> page_remove_rmap() and also before definition of
> page_test_and_clear_dirty(). So most people that will add / remove these
> calls will be warned. OK?
Sounds good, thanks.
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next prev parent reply other threads:[~2012-10-23 21:56 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 15:06 [PATCH] mm: Fix XFS oops due to dirty pages without buffers on s390 Jan Kara
2012-10-22 19:38 ` Andrew Morton
2012-10-23 4:40 ` Hugh Dickins
2012-10-23 10:21 ` Jan Kara
2012-10-23 21:56 ` Andrew Morton [this message]
2012-10-24 8:30 ` Martin Schwidefsky
2012-10-25 20:01 ` Jan Kara
2012-12-14 8:45 ` Martin Schwidefsky
2012-12-17 23:31 ` Hugh Dickins
2012-12-18 7:30 ` Martin Schwidefsky
-- strict thread matches above, loose matches on Subject: below --
2012-10-01 16:26 Jan Kara
2012-10-08 14:28 ` Mel Gorman
2012-10-09 4:24 ` Hugh Dickins
2012-10-09 8:18 ` Martin Schwidefsky
2012-10-09 23:21 ` Hugh Dickins
2012-10-10 21:57 ` Hugh Dickins
2012-10-19 14:38 ` Martin Schwidefsky
2012-10-09 9:32 ` Mel Gorman
2012-10-09 23:00 ` Hugh Dickins
2012-10-09 16:21 ` Jan Kara
2012-10-10 2:19 ` Hugh Dickins
2012-10-10 8:55 ` Jan Kara
2012-10-10 21:28 ` Hugh Dickins
2012-10-11 7:42 ` Martin Schwidefsky
2012-10-10 21:56 ` Dave Chinner
2012-10-11 7:44 ` Martin Schwidefsky
2012-10-17 0:43 ` Jan Kara
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