Messages in this thread | | | Subject | Re: [slubllv7 06/17] slub: Add cmpxchg_double_slab() | From | Eric Dumazet <> | Date | Mon, 11 Jul 2011 21:55:00 +0200 |
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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 ?
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