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SubjectRe: [Xen-devel] [PATCH] xen-blkback: fix memory leak when persistent grants are used
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On Fri, 2014-01-24 at 09:21 +0000, Ian Campbell wrote:
> On Thu, 2014-01-23 at 11:28 -0800, Matt Wilson wrote:
> > From: Matt Rushton <mrushton@amazon.com>
> >
> > Currently shrink_free_pagepool() is called before the pages used for
> > persistent grants are released via free_persistent_gnts(). This
> > results in a memory leak when a VBD that uses persistent grants is
> > torn down.
>
> This may well be the explanation for the memory leak I was observing on
> ARM last night. I'll give it a go and let you know.

Results are a bit inconclusive unfortunately, it seems like I am seeing
some other leak too (or instead).

Totally unscientifically it does seem to be leaking more slowly than
before, so perhaps this patch has helped, but nothing conclusive I'm
afraid.

I don't think that quite qualifies for a Tested-by though, sorry.

Ian.

>
> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > Cc: "Roger Pau Monné" <roger.pau@citrix.com>
> > Cc: Ian Campbell <Ian.Campbell@citrix.com>
> > Cc: David Vrabel <david.vrabel@citrix.com>
> > Cc: linux-kernel@vger.kernel.org
> > Cc: xen-devel@lists.xen.org
> > Cc: Anthony Liguori <aliguori@amazon.com>
> > Signed-off-by: Matt Rushton <mrushton@amazon.com>
> > Signed-off-by: Matt Wilson <msw@amazon.com>
> > ---
> > drivers/block/xen-blkback/blkback.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
> > index 6620b73..30ef7b3 100644
> > --- a/drivers/block/xen-blkback/blkback.c
> > +++ b/drivers/block/xen-blkback/blkback.c
> > @@ -625,9 +625,6 @@ purge_gnt_list:
> > print_stats(blkif);
> > }
> >
> > - /* Since we are shutting down remove all pages from the buffer */
> > - shrink_free_pagepool(blkif, 0 /* All */);
> > -
> > /* Free all persistent grant pages */
> > if (!RB_EMPTY_ROOT(&blkif->persistent_gnts))
> > free_persistent_gnts(blkif, &blkif->persistent_gnts,
> > @@ -636,6 +633,9 @@ purge_gnt_list:
> > BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
> > blkif->persistent_gnt_c = 0;
> >
> > + /* Since we are shutting down remove all pages from the buffer */
> > + shrink_free_pagepool(blkif, 0 /* All */);
> > +
> > if (log_stats)
> > print_stats(blkif);
> >
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


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