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-rw-r--r--mm/slub.c125
1 files changed, 112 insertions, 13 deletions
diff --git a/mm/slub.c b/mm/slub.c
index a6231963cae..ed2846240f9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -130,9 +130,19 @@
*/
#define SLUB_UNIMPLEMENTED (SLAB_DEBUG_INITIAL)
-/* Mininum number of partial slabs */
+/*
+ * Mininum number of partial slabs. These will be left on the partial
+ * lists even if they are empty. kmem_cache_shrink may reclaim them.
+ */
#define MIN_PARTIAL 2
+/*
+ * Maximum number of desirable partial slabs.
+ * The existence of more partial slabs makes kmem_cache_shrink
+ * sort the partial list by the number of objects in the.
+ */
+#define MAX_PARTIAL 10
+
#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
SLAB_POISON | SLAB_STORE_USER)
/*
@@ -1882,7 +1892,7 @@ static int kmem_cache_close(struct kmem_cache *s)
for_each_online_node(node) {
struct kmem_cache_node *n = get_node(s, node);
- free_list(s, n, &n->partial);
+ n->nr_partial -= free_list(s, n, &n->partial);
if (atomic_long_read(&n->nr_slabs))
return 1;
}
@@ -2130,6 +2140,86 @@ void kfree(const void *x)
}
EXPORT_SYMBOL(kfree);
+/*
+ * kmem_cache_shrink removes empty slabs from the partial lists
+ * and then sorts the partially allocated slabs by the number
+ * of items in use. The slabs with the most items in use
+ * come first. New allocations will remove these from the
+ * partial list because they are full. The slabs with the
+ * least items are placed last. If it happens that the objects
+ * are freed then the page can be returned to the page allocator.
+ */
+int kmem_cache_shrink(struct kmem_cache *s)
+{
+ int node;
+ int i;
+ struct kmem_cache_node *n;
+ struct page *page;
+ struct page *t;
+ struct list_head *slabs_by_inuse =
+ kmalloc(sizeof(struct list_head) * s->objects, GFP_KERNEL);
+ unsigned long flags;
+
+ if (!slabs_by_inuse)
+ return -ENOMEM;
+
+ flush_all(s);
+ for_each_online_node(node) {
+ n = get_node(s, node);
+
+ if (!n->nr_partial)
+ continue;
+
+ for (i = 0; i < s->objects; i++)
+ INIT_LIST_HEAD(slabs_by_inuse + i);
+
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ /*
+ * Build lists indexed by the items in use in
+ * each slab or free slabs if empty.
+ *
+ * Note that concurrent frees may occur while
+ * we hold the list_lock. page->inuse here is
+ * the upper limit.
+ */
+ list_for_each_entry_safe(page, t, &n->partial, lru) {
+ if (!page->inuse && slab_trylock(page)) {
+ /*
+ * Must hold slab lock here because slab_free
+ * may have freed the last object and be
+ * waiting to release the slab.
+ */
+ list_del(&page->lru);
+ n->nr_partial--;
+ slab_unlock(page);
+ discard_slab(s, page);
+ } else {
+ if (n->nr_partial > MAX_PARTIAL)
+ list_move(&page->lru,
+ slabs_by_inuse + page->inuse);
+ }
+ }
+
+ if (n->nr_partial <= MAX_PARTIAL)
+ goto out;
+
+ /*
+ * Rebuild the partial list with the slabs filled up
+ * most first and the least used slabs at the end.
+ */
+ for (i = s->objects - 1; i >= 0; i--)
+ list_splice(slabs_by_inuse + i, n->partial.prev);
+
+ out:
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ }
+
+ kfree(slabs_by_inuse);
+ return 0;
+}
+EXPORT_SYMBOL(kmem_cache_shrink);
+
/**
* krealloc - reallocate memory. The contents will remain unchanged.
*
@@ -2382,17 +2472,6 @@ static struct notifier_block __cpuinitdata slab_notifier =
#endif
-/***************************************************************
- * Compatiblility definitions
- **************************************************************/
-
-int kmem_cache_shrink(struct kmem_cache *s)
-{
- flush_all(s);
- return 0;
-}
-EXPORT_SYMBOL(kmem_cache_shrink);
-
#ifdef CONFIG_NUMA
/*****************************************************************
@@ -3169,6 +3248,25 @@ static ssize_t validate_store(struct kmem_cache *s,
}
SLAB_ATTR(validate);
+static ssize_t shrink_show(struct kmem_cache *s, char *buf)
+{
+ return 0;
+}
+
+static ssize_t shrink_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ if (buf[0] == '1') {
+ int rc = kmem_cache_shrink(s);
+
+ if (rc)
+ return rc;
+ } else
+ return -EINVAL;
+ return length;
+}
+SLAB_ATTR(shrink);
+
static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
{
if (!(s->flags & SLAB_STORE_USER))
@@ -3225,6 +3323,7 @@ static struct attribute * slab_attrs[] = {
&poison_attr.attr,
&store_user_attr.attr,
&validate_attr.attr,
+ &shrink_attr.attr,
&alloc_calls_attr.attr,
&free_calls_attr.attr,
#ifdef CONFIG_ZONE_DMA