[PATCH 020/102] xfs: warn if direct reclaim tries to writeback pages

[Mel Gorman]

On Thu, Sep 13, 2012 at 03:12:16PM -0500, Mark Tinguely wrote:
> On 09/05/12 06:32, Mel Gorman wrote:
> >On Mon, Aug 27, 2012 at 02:17:42PM -0400, Christoph Hellwig wrote:
> >>On Thu, Aug 23, 2012 at 03:01:38PM +1000, Dave Chinner wrote:
> >>>From: Mel Gorman<mgorman at suse.de>
> >>>
> >>>Upstream commit: 94054fa3fca1fd78db02cb3d68d5627120f0a1d4
> >>>
> >>>Direct reclaim should never writeback pages.  For now, handle the
> >>>situation and warn about it.  Ultimately, this will be a BUG_ON.
> >>
> >>Is this actually the case on 3.0-stable?
> >>
> >
> >No, it is not. AFAIK, 3.0-stable does not contain [ee72886d: mm: vmscan:
> >do not writeback filesystem pages in direct reclaim] which is the absolute
> >minimum required for commit [94054fa3: xfs: warn if direct reclaim tries
> >to writeback pages] to make sense.
> >
> 
> I hit this warning testing on a linux-30.42 with a x86_64.
> 

Just to be clear, this was linux 3.0.42 with this series of patches
applied on top, right?

> WARNING: at fs/xfs/linux-2.6/xfs_aops.c:961 xfs_vm_writepage+0x63c/0x6a0()
> Hardware name: S2721-533 Thunder i7501 Pro
> Modules linked in: ext4 jbd2 crc16
> Pid: 12122, comm: cp Not tainted 3.0.42 #2

I ask because on 3.0.42 this warning is not present. This patch should
not be merged to 3.0-stable.

-- 
Mel Gorman
SUSE Labs