Messages in this thread | | | Date | Thu, 5 Jul 2012 09:20:04 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 2/3] slub: reduce failure of this_cpu_cmpxchg in put_cpu_partial() after unfreezing |
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On Wed, 4 Jul 2012, Pekka Enberg wrote:
> On Fri, Jun 22, 2012 at 9:22 PM, Joonsoo Kim <js1304@gmail.com> wrote: > > In current implementation, after unfreezing, we doesn't touch oldpage, > > so it remain 'NOT NULL'. When we call this_cpu_cmpxchg() > > with this old oldpage, this_cpu_cmpxchg() is mostly be failed. > > > > We can change value of oldpage to NULL after unfreezing, > > because unfreeze_partial() ensure that all the cpu partial slabs is removed > > from cpu partial list. In this time, we could expect that > > this_cpu_cmpxchg is mostly succeed. > > > > Signed-off-by: Joonsoo Kim <js1304@gmail.com> > > > > diff --git a/mm/slub.c b/mm/slub.c > > index 92f1c0e..531d8ed 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -1968,6 +1968,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) > > local_irq_save(flags); > > unfreeze_partials(s); > > local_irq_restore(flags); > > + oldpage = NULL; > > pobjects = 0; > > pages = 0; > > stat(s, CPU_PARTIAL_DRAIN); > > Makes sense. Christoph, David?
Acked-by: Christoph Lameter <cl@linux.com>
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