extend KSM refcounts to the anon_vma root
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From: Mel Gorman on 27 May 2010 14:00 On Wed, May 26, 2010 at 03:41:24PM -0400, Rik van Riel wrote: > Subject: extend KSM refcounts to the anon_vma root > > KSM reference counts can cause an anon_vma to exist after the processe > it belongs to have already exited. Because the anon_vma lock now lives > in the root anon_vma, we need to ensure that the root anon_vma stays > around until after all the "child" anon_vmas have been freed. > > The obvious way to do this is to have a "child" anon_vma take a > reference to the root in anon_vma_fork. When the anon_vma is freed > at munmap or process exit, we drop the refcount in anon_vma_unlink > and possibly free the root anon_vma. > > The KSM anon_vma reference count function also needs to be modified > to deal with the possibility of freeing 2 levels of anon_vma. The > easiest way to do this is to break out the KSM magic and make it > generic. > > When compiling without CONFIG_KSM, this code is compiled out. > > Signed-off-by: Rik van Riel <riel(a)redhat.com> Acked-by: Mel Gorman <mel(a)csn.ul.ie> -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Mel Gorman on 9 Jun 2010 07:00
On Mon, Jun 07, 2010 at 01:07:01PM +0200, Peter Zijlstra wrote: > From: Rik van Riel <riel(a)redhat.com> > > KSM reference counts can cause an anon_vma to exist after the processe > it belongs to have already exited. Because the anon_vma lock now lives > in the root anon_vma, we need to ensure that the root anon_vma stays > around until after all the "child" anon_vmas have been freed. > > The obvious way to do this is to have a "child" anon_vma take a > reference to the root in anon_vma_fork. When the anon_vma is freed > at munmap or process exit, we drop the refcount in anon_vma_unlink > and possibly free the root anon_vma. > > The KSM anon_vma reference count function also needs to be modified > to deal with the possibility of freeing 2 levels of anon_vma. The > easiest way to do this is to break out the KSM magic and make it > generic. > > When compiling without CONFIG_KSM, this code is compiled out. > > Signed-off-by: Rik van Riel <riel(a)redhat.com> > Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)chello.nl> > LKML-Reference: <20100526154124.04607d04(a)annuminas.surriel.com> Acked-by: Mel Gorman <mel(a)csn.ul.ie > <SNIP> -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |