Re: [PATCH] slub: Use the correct per cpu slab on CPU_DEAD

From: Thomas Gleixner
Date: Tue Oct 30 2012 - 13:01:41 EST


On Tue, 30 Oct 2012, Christoph Lameter wrote:

> On Sat, 27 Oct 2012, Thomas Gleixner wrote:
>
> > Correct this by extending the arguments of unfreeze_partials with the
> > target cpu number and use per_cpu_ptr instead of this_cpu_ptr.
>
> Passing the kmem_cache_cpu pointer instead simplifies this a bit and avoid
> a per_cpu_ptr operations. That reduces code somewhat and results in no
> additional operations for the fast path.
>
>
> Subject: Use correct cpu_slab on dead cpu
>
> Pass a kmem_cache_cpu pointer into unfreeze partials so that a different
> kmem_cache_cpu structure than the local one can be specified.
>
> Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>

Yep. That looks less ugly :)

Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

> Index: linux/mm/slub.c
> ===================================================================
> --- linux.orig/mm/slub.c 2012-10-30 10:23:33.040649727 -0500
> +++ linux/mm/slub.c 2012-10-30 10:25:03.401312250 -0500
> @@ -1874,10 +1874,10 @@ redo:
> *
> * This function must be called with interrupt disabled.
> */
> -static void unfreeze_partials(struct kmem_cache *s)
> +static void unfreeze_partials(struct kmem_cache *s,
> + struct kmem_cache_cpu *c)
> {
> struct kmem_cache_node *n = NULL, *n2 = NULL;
> - struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
> struct page *page, *discard_page = NULL;
>
> while ((page = c->partial)) {
> @@ -1963,7 +1963,7 @@ static int put_cpu_partial(struct kmem_c
> * set to the per node partial list.
> */
> local_irq_save(flags);
> - unfreeze_partials(s);
> + unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
> local_irq_restore(flags);
> oldpage = NULL;
> pobjects = 0;
> @@ -2006,7 +2006,7 @@ static inline void __flush_cpu_slab(stru
> if (c->page)
> flush_slab(s, c);
>
> - unfreeze_partials(s);
> + unfreeze_partials(s, c);
> }
> }
>
>
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