From: Dimitri Sivanich <sivanich@sgi.com>
Here is another cache_reap optimization that reduces latency when applied
after the 'Move cache_reap out of timer context' patch I submitted on 7/14
(for inclusion in -mm next week).
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/slab.c | 37 ++++++-------------------------------
1 files changed, 6 insertions(+), 31 deletions(-)
diff -puN mm/slab.c~locking-optimization-for-cache_reap mm/slab.c
--- 25/mm/slab.c~locking-optimization-for-cache_reap 2004-07-27 23:59:03.403135728 -0700
+++ 25-akpm/mm/slab.c 2004-07-27 23:59:03.408134968 -0700
@@ -2645,27 +2645,6 @@ static void enable_cpucache (kmem_cache_
cachep->name, -err);
}
-static void drain_array(kmem_cache_t *cachep, struct array_cache *ac)
-{
- int tofree;
-
- check_irq_off();
- if (ac->touched) {
- ac->touched = 0;
- } else if (ac->avail) {
- tofree = (ac->limit+4)/5;
- if (tofree > ac->avail) {
- tofree = (ac->avail+1)/2;
- }
- spin_lock(&cachep->spinlock);
- free_block(cachep, ac_entry(ac), tofree);
- spin_unlock(&cachep->spinlock);
- ac->avail -= tofree;
- memmove(&ac_entry(ac)[0], &ac_entry(ac)[tofree],
- sizeof(void*)*ac->avail);
- }
-}
-
static void drain_array_locked(kmem_cache_t *cachep,
struct array_cache *ac, int force)
{
@@ -2719,16 +2698,14 @@ static void cache_reap(void *unused)
goto next;
check_irq_on();
- local_irq_disable();
- drain_array(searchp, ac_data(searchp));
- if(time_after(searchp->lists.next_reap, jiffies))
- goto next_irqon;
+ spin_lock_irq(&searchp->spinlock);
+
+ drain_array_locked(searchp, ac_data(searchp), 0);
- spin_lock(&searchp->spinlock);
- if(time_after(searchp->lists.next_reap, jiffies)) {
+ if(time_after(searchp->lists.next_reap, jiffies))
goto next_unlock;
- }
+
searchp->lists.next_reap = jiffies + REAPTIMEOUT_LIST3;
if (searchp->lists.shared)
@@ -2761,9 +2738,7 @@ static void cache_reap(void *unused)
spin_lock_irq(&searchp->spinlock);
} while(--tofree > 0);
next_unlock:
- spin_unlock(&searchp->spinlock);
-next_irqon:
- local_irq_enable();
+ spin_unlock_irq(&searchp->spinlock);
next:
;
}
_