Re: [Xen-devel] [PATCH] xen-blkback: fix memory leak when persistent grants are used

[Matt Wilson <msw@xxxxxxxxx>]

On Fri, Jan 24, 2014 at 03:36:22PM +0000, Ian Campbell wrote:
> 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@xxxxxxxxxx>
> > > 
> > > 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.

Testing here looks good. I don't know if perhaps something else is
going on with ARM...

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

How about an Acked-by? ;-)

--msw

> Ian. 
> 
> > 
> > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > > Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
> > > Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
> > > Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> > > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > > Cc: xen-devel@xxxxxxxxxxxxx
> > > Cc: Anthony Liguori <aliguori@xxxxxxxxxx>
> > > Signed-off-by: Matt Rushton <mrushton@xxxxxxxxxx>
> > > Signed-off-by: Matt Wilson <msw@xxxxxxxxxx>
> > > ---
> > >  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@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel
> 
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel