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| author | Benjamin LaHaise <bcrl@linux.intel.com> | 2006-02-01 03:05:30 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-01 08:53:15 -0800 |
| commit | 9884fd8df195fe48d4e1be2279b419be96127cae (patch) | |
| tree | 1438571d206c1d488efb8454c64ae00c51438a2e /mm/slab.c | |
| parent | c84db23c6e587d3ab00a41c51fedf758e1f6ecd4 (diff) | |
| download | op-kernel-dev-9884fd8df195fe48d4e1be2279b419be96127cae.zip op-kernel-dev-9884fd8df195fe48d4e1be2279b419be96127cae.tar.gz | |
[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/slab.c')
| -rw-r--r-- | mm/slab.c | 6 |
1 files changed, 3 insertions, 3 deletions
@@ -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); |
