Re: slub: use irqsafe_cpu_cmpxchg for put_cpu_partial

[Eric Dumazet]

Le mercredi 23 novembre 2011 Ã 09:14 -0600, Christoph Lameter a Ãcrit :

> I think he only tested the patch that he showed us. Here is the patch
> cleaned up. Do you Want me to feed you the debug fixes patch by patch as
> well?
> 
> Subject: slub: use irqsafe_cpu_cmpxchg for put_cpu_partial
> 
> The cmpxchg must be irq safe. The fallback for this_cpu_cmpxchg only
> disables preemption which results in per cpu partial page operation
> potentially failing on non x86 platforms.
> 
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
> 
> ---
>  mm/slub.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c	2011-11-23 09:10:48.000000000 -0600
> +++ linux-2.6/mm/slub.c	2011-11-23 09:10:57.000000000 -0600
> @@ -1969,7 +1969,7 @@ int put_cpu_partial(struct kmem_cache *s
>  		page->pobjects = pobjects;
>  		page->next = oldpage;
> 
> -	} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
> +	} while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
>  	stat(s, CPU_PARTIAL_FREE);
>  	return pobjects;
>  }

Acked-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>

Thanks !


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/