atomic_long_t pages_allocated;
struct zs_pool_stats stats;
+
+ /* Compact classes */
+ struct shrinker shrinker;
+ /*
+ * To signify that register_shrinker() was successful
+ * and unregister_shrinker() will not Oops.
+ */
+ bool shrinker_enabled;
#ifdef CONFIG_ZSMALLOC_STAT
struct dentry *stat_dentry;
#endif
static void destroy_handle_cache(struct zs_pool *pool)
{
- if (pool->handle_cachep)
- kmem_cache_destroy(pool->handle_cachep);
+ kmem_cache_destroy(pool->handle_cachep);
}
static unsigned long alloc_handle(struct zs_pool *pool)
#ifdef CONFIG_ZPOOL
-static void *zs_zpool_create(char *name, gfp_t gfp, struct zpool_ops *zpool_ops,
+static void *zs_zpool_create(char *name, gfp_t gfp,
+ const struct zpool_ops *zpool_ops,
struct zpool *zpool)
{
return zs_create_pool(name, gfp);
if (fullness >= _ZS_NR_FULLNESS_GROUPS)
return;
- head = &class->fullness_list[fullness];
- if (*head)
- list_add_tail(&page->lru, &(*head)->lru);
-
- *head = page;
zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
+
+ head = &class->fullness_list[fullness];
+ if (!*head) {
+ *head = page;
+ return;
+ }
+
+ /*
+ * We want to see more ZS_FULL pages and less almost
+ * empty/full. Put pages with higher ->inuse first.
+ */
+ list_add_tail(&page->lru, &(*head)->lru);
+ if (page->inuse >= (*head)->inuse)
+ *head = page;
}
/*
static struct page *isolate_source_page(struct size_class *class)
{
- struct page *page;
+ int i;
+ struct page *page = NULL;
- page = class->fullness_list[ZS_ALMOST_EMPTY];
- if (page)
- remove_zspage(page, class, ZS_ALMOST_EMPTY);
+ for (i = ZS_ALMOST_EMPTY; i >= ZS_ALMOST_FULL; i--) {
+ page = class->fullness_list[i];
+ if (!page)
+ continue;
+
+ remove_zspage(page, class, i);
+ break;
+ }
return page;
}
*
* Based on the number of unused allocated objects calculate
* and return the number of pages that we can free.
- *
- * Should be called under class->lock.
*/
static unsigned long zs_can_compact(struct size_class *class)
{
unsigned long obj_wasted;
- if (!zs_stat_get(class, CLASS_ALMOST_EMPTY))
- return 0;
-
obj_wasted = zs_stat_get(class, OBJ_ALLOCATED) -
zs_stat_get(class, OBJ_USED);
obj_wasted /= get_maxobj_per_zspage(class->size,
class->pages_per_zspage);
- return obj_wasted * get_pages_per_zspage(class->size);
+ return obj_wasted * class->pages_per_zspage;
}
static void __zs_compact(struct zs_pool *pool, struct size_class *class)
putback_zspage(pool, class, dst_page);
if (putback_zspage(pool, class, src_page) == ZS_EMPTY)
- pool->stats.pages_compacted +=
- get_pages_per_zspage(class->size);
+ pool->stats.pages_compacted += class->pages_per_zspage;
spin_unlock(&class->lock);
cond_resched();
spin_lock(&class->lock);
}
EXPORT_SYMBOL_GPL(zs_pool_stats);
+static unsigned long zs_shrinker_scan(struct shrinker *shrinker,
+ struct shrink_control *sc)
+{
+ unsigned long pages_freed;
+ struct zs_pool *pool = container_of(shrinker, struct zs_pool,
+ shrinker);
+
+ pages_freed = pool->stats.pages_compacted;
+ /*
+ * Compact classes and calculate compaction delta.
+ * Can run concurrently with a manually triggered
+ * (by user) compaction.
+ */
+ pages_freed = zs_compact(pool) - pages_freed;
+
+ return pages_freed ? pages_freed : SHRINK_STOP;
+}
+
+static unsigned long zs_shrinker_count(struct shrinker *shrinker,
+ struct shrink_control *sc)
+{
+ int i;
+ struct size_class *class;
+ unsigned long pages_to_free = 0;
+ struct zs_pool *pool = container_of(shrinker, struct zs_pool,
+ shrinker);
+
+ if (!pool->shrinker_enabled)
+ return 0;
+
+ for (i = zs_size_classes - 1; i >= 0; i--) {
+ class = pool->size_class[i];
+ if (!class)
+ continue;
+ if (class->index != i)
+ continue;
+
+ pages_to_free += zs_can_compact(class);
+ }
+
+ return pages_to_free;
+}
+
+static void zs_unregister_shrinker(struct zs_pool *pool)
+{
+ if (pool->shrinker_enabled) {
+ unregister_shrinker(&pool->shrinker);
+ pool->shrinker_enabled = false;
+ }
+}
+
+static int zs_register_shrinker(struct zs_pool *pool)
+{
+ pool->shrinker.scan_objects = zs_shrinker_scan;
+ pool->shrinker.count_objects = zs_shrinker_count;
+ pool->shrinker.batch = 0;
+ pool->shrinker.seeks = DEFAULT_SEEKS;
+
+ return register_shrinker(&pool->shrinker);
+}
+
/**
* zs_create_pool - Creates an allocation pool to work from.
* @flags: allocation flags used to allocate pool metadata
if (zs_pool_stat_create(name, pool))
goto err;
+ /*
+ * Not critical, we still can use the pool
+ * and user can trigger compaction manually.
+ */
+ if (zs_register_shrinker(pool) == 0)
+ pool->shrinker_enabled = true;
return pool;
err:
{
int i;
+ zs_unregister_shrinker(pool);
zs_pool_stat_destroy(pool);
for (i = 0; i < zs_size_classes; i++) {