lkml.org 
[lkml]   [2011]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [slubllv7 06/17] slub: Add cmpxchg_double_slab()
From
Date
Le mercredi 01 juin 2011 à 12:25 -0500, Christoph Lameter a écrit :
> pièce jointe document texte brut (cmpxchg_double_slab)
> Add a function that operates on the second doubleword in the page struct
> and manipulates the object counters, the freelist and the frozen attribute.
>
> Signed-off-by: Christoph Lameter <cl@linux.com>
>
> ---
> include/linux/slub_def.h | 1
> mm/slub.c | 65 +++++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 61 insertions(+), 5 deletions(-)
>
> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c 2011-05-31 11:57:59.622937422 -0500
> +++ linux-2.6/mm/slub.c 2011-05-31 12:03:16.652935392 -0500
> @@ -131,6 +131,9 @@ static inline int kmem_cache_debug(struc
> /* Enable to test recovery from slab corruption on boot */
> #undef SLUB_RESILIENCY_TEST
>
> +/* Enable to log cmpxchg failures */
> +#undef SLUB_DEBUG_CMPXCHG
> +
> /*
> * Mininum number of partial slabs. These will be left on the partial
> * lists even if they are empty. kmem_cache_shrink may reclaim them.
> @@ -170,6 +173,7 @@ static inline int kmem_cache_debug(struc
>
> /* Internal SLUB flags */
> #define __OBJECT_POISON 0x80000000UL /* Poison object */
> +#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
>
> static int kmem_size = sizeof(struct kmem_cache);
>
> @@ -338,6 +342,37 @@ static inline int oo_objects(struct kmem
> return x.x & OO_MASK;
> }
>
> +static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
> + void *freelist_old, unsigned long counters_old,
> + void *freelist_new, unsigned long counters_new,
> + const char *n)
> +{
> +#ifdef CONFIG_CMPXCHG_DOUBLE
> + if (s->flags & __CMPXCHG_DOUBLE) {
> + if (cmpxchg_double(&page->freelist,
> + freelist_old, counters_old,
> + freelist_new, counters_new))
> + return 1;
> + } else
> +#endif
> + {
> + if (page->freelist == freelist_old && page->counters == counters_old) {
> + page->freelist = freelist_new;
> + page->counters = counters_new;
> + return 1;
> + }
> + }

This works only on 64bit arches, where page->counters get all following
fields combined : inuse, objects, frozen, _count

On 32bit arch, I am afraid you have to disable the cmpxchg_double()
thing ?




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

\
 
 \ /
  Last update: 2011-07-11 21:57    [W:0.122 / U:0.832 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site