[PATCH 1/3] slub: prefetch next freelist pointer in __slab_alloc()

[Joonsoo Kim]

Commit 0ad9500e16fe24aa55809a2b00e0d2d0e658fc71 ('slub: prefetch
next freelist pointer in slab_alloc') add prefetch instruction to
fast path of allocation.

Same benefit is also available in slow path of allocation, but it is not
large portion of overall allocation. Nevertheless we could get
some benifit from it, so prefetch next freelist pointer in __slab_alloc.

Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>

diff --git a/mm/slub.c b/mm/slub.c
index f96d8bc..92f1c0e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2248,6 +2248,7 @@ load_freelist:
 	VM_BUG_ON(!c->page->frozen);
 	c->freelist = get_freepointer(s, freelist);
 	c->tid = next_tid(c->tid);
+	prefetch_freepointer(s, c->freelist);
 	local_irq_restore(flags);
 	return freelist;
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/