[3.16.y-ckt,stable] Patch "rbd: rbd workqueues need a resque worker" has been added to staging queue

This is a note to let you know that I have just added a patch titled

    rbd: rbd workqueues need a resque worker

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From c999f9b8bccf1a1142c1e7372c1ecb197a3464a1 Mon Sep 17 00:00:00 2001
From: Ilya Dryomov <idryomov@redhat.com>
Date: Fri, 10 Oct 2014 18:36:07 +0400
Subject: rbd: rbd workqueues need a resque worker

commit 792c3a914910bd34302c5345578f85cfcb5e2c01 upstream.

Need to use WQ_MEM_RECLAIM for our workqueues to prevent I/O lockups
under memory pressure - we sit on the memory reclaim path.

Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Tested-by: Micha Krause <micha@krausam.de>
Reviewed-by: Sage Weil <sage@redhat.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/block/rbd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--
2.1.0

On Mon, Nov 17, 2014 at 05:38:51PM +0400, Ilya Dryomov wrote:
> On Mon, Nov 17, 2014 at 2:16 PM, Luis Henriques
> <luis.henriques@canonical.com> wrote:
> > This is a note to let you know that I have just added a patch titled
> >
> >     rbd: rbd workqueues need a resque worker
> >
> > to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
> > which can be found at:
> >
> >  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue
> >
> > This patch is scheduled to be released in version 3.16.7-ckt2.
> >
> > If you, or anyone else, feels it should not be added to this tree, please
> > reply to this email.
> >
> > For more information about the 3.16.y-ckt tree, see
> > https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
> >
> > Thanks.
> > -Luis
> >
> > ------
> >
> > From c999f9b8bccf1a1142c1e7372c1ecb197a3464a1 Mon Sep 17 00:00:00 2001
> > From: Ilya Dryomov <idryomov@redhat.com>
> > Date: Fri, 10 Oct 2014 18:36:07 +0400
> > Subject: rbd: rbd workqueues need a resque worker
> >
> > commit 792c3a914910bd34302c5345578f85cfcb5e2c01 upstream.
> >
> > Need to use WQ_MEM_RECLAIM for our workqueues to prevent I/O lockups
> > under memory pressure - we sit on the memory reclaim path.
> >
> > Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
> > Tested-by: Micha Krause <micha@krausam.de>
> > Reviewed-by: Sage Weil <sage@redhat.com>
> > [ luis: backported to 3.16: adjusted context ]
> 
> I sent a backport for this to stable@ a while ago:
> 
> Message-Id: <1413389385-8434-1-git-send-email-idryomov@redhat.com>
> 
> While your fixup is obviously correct, mine also folds in an error path
> fix, so if you could apply it instead it would be great.
> 
> Thanks,
> 
>                 Ilya

Ah, sorry I missed that.

Anyway, instead of folding that error path fix, I would like to
propose to cherry-pick the following commits instead:

 58d1362b50dc rbd: avoid format-security warning inside alloc_workqueue()
 255939e783d8 rbd: fix error return code in rbd_dev_device_setup()
 792c3a914910 rbd: rbd workqueues need a resque worker

These are all clean cherry-picks in the 3.16 kernel, and I believe the
end result will be the same as the backport you proposed but without
folding commits.

Cheers,
--
Luís