On Thu, Sep 20, 2007 at 10:36:13AM -0700, Christoph Lameter wrote:
> On Thu, 20 Sep 2007, Alexey Dobriyan wrote:
> > The winner is
> > slub-avoid-touching-page-struct-when-freeing-to-per-cpu-slab.patch
> > Blind bisecting pointed to it and reverting the patch from full -mm makes
> > the problem go away
>
> Hmmm.. This means likely that the c->node is used somewhere for
> indexing.... Ahhh... If we count objects for sysfs output then c->node may
> be used to index into the statistics array. The offset from the poison
> also makes sense now since we increment values there.
>
> Does this patch fix the issue?
Yes, it does.
> SLUB: Fix slab object counting.
>
> We can only use the node value of the per cpu structure for counting if it
> is positive. A negative value indicates that the slab is not valid.
>
> Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>
>
> ---
> mm/slub.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> Index: linux-2.6.23-rc6-mm1/mm/slub.c
> ===================================================================
> --- linux-2.6.23-rc6-mm1.orig/mm/slub.c 2007-09-20 10:31:04.000000000
> -0700
> +++ linux-2.6.23-rc6-mm1/mm/slub.c 2007-09-20 10:32:19.000000000 -0700
> @@ -3412,12 +3412,16 @@ static unsigned long slab_objects(struct
>
> for_each_possible_cpu(cpu) {
> struct page *page;
> + int node;
> struct kmem_cache_cpu *c = get_cpu_slab(s, cpu);
>
> if (!c)
> continue;
>
> page = c->page;
> + node = c->node;
> + if (node < 0)
> + continue;
> if (page) {
> if (flags & SO_CPU) {
> int x = 0;
> @@ -3427,9 +3431,9 @@ static unsigned long slab_objects(struct
> else
> x = 1;
> total += x;
> - nodes[c->node] += x;
> + nodes[node] += x;
> }
> - per_cpu[c->node]++;
> + per_cpu[node]++;
> }
> }
>
-
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