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Subject: Re: [PATCH v8 3/5] virtio_balloon: introduce migration primitives
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From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 21 Aug 2012 17:34:20 +0200
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Rusty Russell <rusty@rustcorp.com.au>, Rik van Riel <riel@redhat.com>, Mel Gorman <mel@csn.ul.ie>, Andi Kleen <andi@firstfloor.org>, Andrew Morton <akpm@linux-foundation.org>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Minchan Kim <minchan@kernel.org>

On Tue, 2012-08-21 at 17:40 +0300, Michael S. Tsirkin wrote:
> > +     vb->balloon_status =3D BALLOON_REMOVAL;
>=20
> This needs some kind of barrier.
>=20
> >       kthread_stop(vb->thread);=20

kthread_stop() implies an smp_wmb() [ because it needs to do a wakeup ].

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Subject: Re: [PATCH v8 3/5] virtio_balloon: introduce migration primitives
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From: Peter Zijlstra <peterz@infradead.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>, linux-mm@kvack.org,
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Date: Tue, 21 Aug 2012 17:34:20 +0200
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On Tue, 2012-08-21 at 17:40 +0300, Michael S. Tsirkin wrote:
> > +     vb->balloon_status = BALLOON_REMOVAL;
> 
> This needs some kind of barrier.
> 
> >       kthread_stop(vb->thread); 

kthread_stop() implies an smp_wmb() [ because it needs to do a wakeup ].