Messages in this thread Patch in this message | | | Date | Mon, 13 Aug 2007 23:56:57 -0700 | From | "Siddha, Suresh B" <> | Subject | Re: [patch] slab: revert "slab: fix alien cache handling" |
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On Mon, Aug 13, 2007 at 01:58:48PM -0700, Christoph Lameter wrote: > On Mon, 13 Aug 2007, Siddha, Suresh B wrote: > > > Can we revert git commit 3cdc0ed0cea50ea08dd146c1bbc82b1bcc2e1b80 ? > > Only if you find another way to fix the bug that is addressed there.
Does the appended version fix both the issues? Name alien in cache_free_alien is confusing, as the function does two things. free through alien caches or direct remote free..
thanks, suresh ---
Skip calling cache_free_alien() when the platform is not numa capable. This will avoid cache misses that happen while accessing slabp (which is per page memory reference) to get nodeid. Instead use a global variable to skip the call, which is mostly likely to be present in the cache.
This gives a 0.8% performance boost with the database oltp workload on a quad-core SMP platform and by any means the number is not small :)
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> ---
diff --git a/mm/slab.c b/mm/slab.c index a684778..6f6abef 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -883,6 +883,7 @@ static void __slab_error(const char *function, struct kmem_cache *cachep, */ static int use_alien_caches __read_mostly = 1; +static int numa_platform __read_mostly = 1; static int __init noaliencache_setup(char *s) { use_alien_caches = 0; @@ -1399,8 +1400,10 @@ void __init kmem_cache_init(void) int order; int node; - if (num_possible_nodes() == 1) + if (num_possible_nodes() == 1) { use_alien_caches = 0; + numa_platform = 0; + } for (i = 0; i < NUM_INIT_LISTS; i++) { kmem_list3_init(&initkmem_list3[i]); @@ -3558,7 +3561,14 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp) check_irq_off(); objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0)); - if (cache_free_alien(cachep, objp)) + /* + * Skip calling cache_free_alien() when the platform is not numa. + * This will avoid cache misses that happen while accessing slabp (which + * is per page memory reference) to get nodeid. Instead use a global + * variable to skip the call, which is mostly likely to be present in + * the cache. + */ + if (numa_platform && cache_free_alien(cachep, objp)) return; if (likely(ac->avail < ac->limit)) { - 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/
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