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authorBenjamin LaHaise <bcrl@linux.intel.com>2006-02-01 03:05:30 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-01 08:53:15 -0800
commit9884fd8df195fe48d4e1be2279b419be96127cae (patch)
tree1438571d206c1d488efb8454c64ae00c51438a2e /mm
parentc84db23c6e587d3ab00a41c51fedf758e1f6ecd4 (diff)
[PATCH] Use 32 bit division in slab_put_obj()
Improve the performance of slab_put_obj(). Without the cast, gcc considers ptrdiff_t a 64 bit signed integer and ends up emitting code to use a full signed 128 bit divide on EM64T, which is substantially slower than a 32 bit unsigned divide. I noticed this when looking at the profile of a case where the slab balance is just on edge and thrashes back and forth freeing a block. Signed-off-by: Benjamin LaHaise <benjamin.c.lahaise@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/slab.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 6f8495e2185b..88082ae15736 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1398,7 +1398,7 @@ static void check_poison_obj(kmem_cache_t *cachep, void *objp)
struct slab *slabp = page_get_slab(virt_to_page(objp));
int objnr;
- objnr = (objp - slabp->s_mem) / cachep->objsize;
+ objnr = (unsigned)(objp - slabp->s_mem) / cachep->objsize;
if (objnr) {
objp = slabp->s_mem + (objnr - 1) * cachep->objsize;
realobj = (char *)objp + obj_dbghead(cachep);
@@ -2341,7 +2341,7 @@ static void *cache_free_debugcheck(kmem_cache_t *cachep, void *objp,
if (cachep->flags & SLAB_STORE_USER)
*dbg_userword(cachep, objp) = caller;
- objnr = (objp - slabp->s_mem) / cachep->objsize;
+ objnr = (unsigned)(objp - slabp->s_mem) / cachep->objsize;
BUG_ON(objnr >= cachep->num);
BUG_ON(objp != slabp->s_mem + objnr * cachep->objsize);
@@ -2699,7 +2699,7 @@ static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects,
slabp = page_get_slab(virt_to_page(objp));
l3 = cachep->nodelists[node];
list_del(&slabp->list);
- objnr = (objp - slabp->s_mem) / cachep->objsize;
+ objnr = (unsigned)(objp - slabp->s_mem) / cachep->objsize;
check_spinlock_acquired_node(cachep, node);
check_slabp(cachep, slabp);