From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: [patch 10/23] SLUB: Sort slab cache list and establish maximum objects for defrag slabs Date: Tue, 06 Nov 2007 17:11:40 -0800 Message-ID: <20071107011228.858031377@sgi.com> References: <20071107011130.382244340@sgi.com> Return-path: Content-Disposition: inline; filename=0007-slab_defrag_determine_maximum_objects.patch Sender: linux-kernel-owner@vger.kernel.org To: akpm@linux-foundatin.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman List-Id: linux-mm.kvack.org When defragmenting slabs then it is advantageous to have all defragmentable slabs together at the beginning of the list so that we do not have to scan the complete list. When adding a slab cache put defragmentable caches first and others last. Determine the maximum number of objects in defragmentable slabs. This allows to size the allocation of arrays holding refs to these objects later. Reviewed-by: Rik van Riel Signed-off-by: Christoph Lameter --- mm/slub.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) Index: linux-2.6/mm/slub.c =================================================================== --- linux-2.6.orig/mm/slub.c 2007-11-06 12:37:51.000000000 -0800 +++ linux-2.6/mm/slub.c 2007-11-06 12:37:54.000000000 -0800 @@ -198,6 +198,9 @@ static enum { static DECLARE_RWSEM(slub_lock); static LIST_HEAD(slab_caches); +/* Maximum objects in defragmentable slabs */ +static unsigned int max_defrag_slab_objects = 0; + /* * Tracking user of a slab. */ @@ -2546,7 +2549,7 @@ static struct kmem_cache *create_kmalloc flags, NULL)) goto panic; - list_add(&s->list, &slab_caches); + list_add_tail(&s->list, &slab_caches); up_write(&slub_lock); if (sysfs_slab_add(s)) goto panic; @@ -2760,6 +2763,13 @@ void kfree(const void *x) } EXPORT_SYMBOL(kfree); +static inline void *alloc_scratch(void) +{ + return kmalloc(max_defrag_slab_objects * sizeof(void *) + + BITS_TO_LONGS(max_defrag_slab_objects) * sizeof(unsigned long), + GFP_KERNEL); +} + void kmem_cache_setup_defrag(struct kmem_cache *s, void *(*get)(struct kmem_cache *, int nr, void **), void (*kick)(struct kmem_cache *, int nr, void **, void *private)) @@ -2771,6 +2781,11 @@ void kmem_cache_setup_defrag(struct kmem BUG_ON(!s->ctor); s->get = get; s->kick = kick; + down_write(&slub_lock); + list_move(&s->list, &slab_caches); + if (s->objects > max_defrag_slab_objects) + max_defrag_slab_objects = s->objects; + up_write(&slub_lock); } EXPORT_SYMBOL(kmem_cache_setup_defrag); @@ -3159,7 +3174,7 @@ struct kmem_cache *kmem_cache_create(con if (s) { if (kmem_cache_open(s, GFP_KERNEL, name, size, align, flags, ctor)) { - list_add(&s->list, &slab_caches); + list_add_tail(&s->list, &slab_caches); up_write(&slub_lock); if (sysfs_slab_add(s)) goto err; --