The patch titled
Subject: mm/slab: don't keep free slabs if free_objects exceeds free_limit
has been added to the -mm tree. Its filename is
mm-slab-dont-keep-free-slabs-if-free_objects-exceeds-free_limit.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slab-dont-keep-free-slabs-if-free_objects-exceeds-free_limit.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-dont-keep-free-slabs-if-free_objects-exceeds-free_limit.patch
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From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: mm/slab: don't keep free slabs if free_objects exceeds free_limit
Currently, determination to free a slab is done whenever free object is
put into the slab. This has a problem that free slabs are not freed even
if we have free slabs and have more free_objects than free_limit when
processed slab isn't a free slab. This would cause to keep too much
memory in the slab subsystem. This patch try to fix it by checking number
of free object after all free work is done. If there is free slab at that
time, we can free it so we keep free slab as minimal as possible.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff -puN mm/slab.c~mm-slab-dont-keep-free-slabs-if-free_objects-exceeds-free_limit mm/slab.c
--- a/mm/slab.c~mm-slab-dont-keep-free-slabs-if-free_objects-exceeds-free_limit
+++ a/mm/slab.c
@@ -3265,6 +3265,9 @@ static void free_block(struct kmem_cache
{
int i;
struct kmem_cache_node *n = get_node(cachep, node);
+ struct page *page;
+
+ n->free_objects += nr_objects;
for (i = 0; i < nr_objects; i++) {
void *objp;
@@ -3277,17 +3280,11 @@ static void free_block(struct kmem_cache
check_spinlock_acquired_node(cachep, node);
slab_put_obj(cachep, page, objp);
STATS_DEC_ACTIVE(cachep);
- n->free_objects++;
/* fixup slab chains */
- if (page->active == 0) {
- if (n->free_objects > n->free_limit) {
- n->free_objects -= cachep->num;
- list_add_tail(&page->lru, list);
- } else {
- list_add(&page->lru, &n->slabs_free);
- }
- } else {
+ if (page->active == 0)
+ list_add(&page->lru, &n->slabs_free);
+ else {
/* Unconditionally move a slab to the end of the
* partial list on free - maximum time for the
* other objects to be freed, too.
@@ -3295,6 +3292,14 @@ static void free_block(struct kmem_cache
list_add_tail(&page->lru, &n->slabs_partial);
}
}
+
+ while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) {
+ n->free_objects -= cachep->num;
+
+ page = list_last_entry(&n->slabs_free, struct page, lru);
+ list_del(&page->lru);
+ list_add(&page->lru, list);
+ }
}
static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
mm-page_ref-use-page_ref-helper-instead-of-direct-modification-of-_count.patch
mm-rename-_count-field-of-the-struct-page-to-_refcount.patch
mm-slab-hold-a-slab_mutex-when-calling-__kmem_cache_shrink.patch
mm-slab-remove-bad_alien_magic-again.patch
mm-slab-drain-the-free-slab-as-much-as-possible.patch
mm-slab-factor-out-kmem_cache_node-initialization-code.patch
mm-slab-clean-up-kmem_cache_node-setup.patch
mm-slab-dont-keep-free-slabs-if-free_objects-exceeds-free_limit.patch
mm-slab-racy-access-modify-the-slab-color.patch
mm-slab-make-cache_grow-handle-the-page-allocated-on-arbitrary-node.patch
mm-slab-separate-cache_grow-to-two-parts.patch
mm-slab-refill-cpu-cache-through-a-new-slab-without-holding-a-node-lock.patch
mm-slab-lockless-decision-to-grow-cache.patch
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