[Devel] Re: [PATCH v3 03/16] slab: Ignore the cflgs bit in cache creation

[Tejun Heo]

On Tue, Sep 18, 2012 at 06:11:57PM +0400, Glauber Costa wrote:
> No cache should ever pass that as a creation flag, since this bit is
> used to mark an internal decision of the slab about object placement. We
> can just ignore this bit if it happens to be passed (such as when
> duplicating a cache in the kmem memcg patches)
> 
> Signed-off-by: Glauber Costa <glommer at parallels.com>
> CC: Christoph Lameter <cl at linux.com>
> CC: Pekka Enberg <penberg at cs.helsinki.fi>
> CC: David Rientjes <rientjes at google.com>
> ---
>  mm/slab.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/slab.c b/mm/slab.c
> index a7ed60f..ccf496c 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -2373,6 +2373,7 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
>  	int err;
>  	size_t size = cachep->size;
>  
> +	flags &= ~CFLGS_OFF_SLAB;

A comment explaining why this is necessary wouldn't hurt.

Thanks.

-- 
tejun