diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index d06f9150b9da0bbd76d95b740736c55df2cba0f5..9445bee6b0140b071e9134805e318c145bacea5b 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -271,12 +271,13 @@ struct zspage {
#ifdef CONFIG_ZPOOL
/* links the zspage to the lru list in the pool */
struct list_head lru;
+ bool under_reclaim;
+ /* list of unfreed handles whose objects have been reclaimed */
+ unsigned long *deferred_handles;
#endif
struct zs_pool *pool;
-#ifdef CONFIG_COMPACTION
rwlock_t lock;
-#endif
};
struct mapping_area {
@@ -297,10 +298,11 @@ static bool ZsHugePage(struct zspage *zspage)
return zspage->huge;
}
-#ifdef CONFIG_COMPACTION
static void migrate_lock_init(struct zspage *zspage);
static void migrate_read_lock(struct zspage *zspage);
static void migrate_read_unlock(struct zspage *zspage);
+
+#ifdef CONFIG_COMPACTION
static void migrate_write_lock(struct zspage *zspage);
static void migrate_write_lock_nested(struct zspage *zspage);
static void migrate_write_unlock(struct zspage *zspage);
@@ -308,9 +310,6 @@ static void kick_deferred_free(struct zs_pool *pool);
static void init_deferred_free(struct zs_pool *pool);
static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
#else
-static void migrate_lock_init(struct zspage *zspage) {}
-static void migrate_read_lock(struct zspage *zspage) {}
-static void migrate_read_unlock(struct zspage *zspage) {}
static void migrate_write_lock(struct zspage *zspage) {}
static void migrate_write_lock_nested(struct zspage *zspage) {}
static void migrate_write_unlock(struct zspage *zspage) {}
@@ -413,6 +412,27 @@ static void zs_zpool_free(void *pool, unsigned long handle)
zs_free(pool, handle);
}
+static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries);
+
+static int zs_zpool_shrink(void *pool, unsigned int pages,
+ unsigned int *reclaimed)
+{
+ unsigned int total = 0;
+ int ret = -EINVAL;
+
+ while (total < pages) {
+ ret = zs_reclaim_page(pool, 8);
+ if (ret < 0)
+ break;
+ total++;
+ }
+
+ if (reclaimed)
+ *reclaimed = total;
+
+ return ret;
+}
+
static void *zs_zpool_map(void *pool, unsigned long handle,
enum zpool_mapmode mm)
{
@@ -451,6 +471,7 @@ static struct zpool_driver zs_zpool_driver = {
.malloc_support_movable = true,
.malloc = zs_zpool_malloc,
.free = zs_zpool_free,
+ .shrink = zs_zpool_shrink,
.map = zs_zpool_map,
.unmap = zs_zpool_unmap,
.total_size = zs_zpool_total_size,
@@ -924,6 +945,25 @@ static int trylock_zspage(struct zspage *zspage)
return 0;
}
+#ifdef CONFIG_ZPOOL
+/*
+ * Free all the deferred handles whose objects are freed in zs_free.
+ */
+static void free_handles(struct zs_pool *pool, struct zspage *zspage)
+{
+ unsigned long handle = (unsigned long)zspage->deferred_handles;
+
+ while (handle) {
+ unsigned long nxt_handle = handle_to_obj(handle);
+
+ cache_free_handle(pool, handle);
+ handle = nxt_handle;
+ }
+}
+#else
+static inline void free_handles(struct zs_pool *pool, struct zspage *zspage) {}
+#endif
+
static void __free_zspage(struct zs_pool *pool, struct size_class *class,
struct zspage *zspage)
{
@@ -938,6 +978,9 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
VM_BUG_ON(get_zspage_inuse(zspage));
VM_BUG_ON(fg != ZS_EMPTY);
+ /* Free all deferred handles from zs_free */
+ free_handles(pool, zspage);
+
next = page = get_first_page(zspage);
do {
VM_BUG_ON_PAGE(!PageLocked(page), page);
@@ -1023,6 +1066,8 @@ static void init_zspage(struct size_class *class, struct zspage *zspage)
#ifdef CONFIG_ZPOOL
INIT_LIST_HEAD(&zspage->lru);
+ zspage->under_reclaim = false;
+ zspage->deferred_handles = NULL;
#endif
set_freeobj(zspage, 0);
@@ -1572,12 +1617,26 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
obj_free(class->size, obj);
class_stat_dec(class, OBJ_USED, 1);
+
+#ifdef CONFIG_ZPOOL
+ if (zspage->under_reclaim) {
+ /*
+ * Reclaim needs the handles during writeback. It'll free
+ * them along with the zspage when it's done with them.
+ *
+ * Record current deferred handle at the memory location
+ * whose address is given by handle.
+ */
+ record_obj(handle, (unsigned long)zspage->deferred_handles);
+ zspage->deferred_handles = (unsigned long *)handle;
+ spin_unlock(&pool->lock);
+ return;
+ }
+#endif
fullness = fix_fullness_group(class, zspage);
- if (fullness != ZS_EMPTY)
- goto out;
+ if (fullness == ZS_EMPTY)
+ free_zspage(pool, class, zspage);
- free_zspage(pool, class, zspage);
-out:
spin_unlock(&pool->lock);
cache_free_handle(pool, handle);
}
@@ -1777,7 +1836,7 @@ static enum fullness_group putback_zspage(struct size_class *class,
return fullness;
}
-#ifdef CONFIG_COMPACTION
+#if defined(CONFIG_ZPOOL) || defined(CONFIG_COMPACTION)
/*
* To prevent zspage destroy during migration, zspage freeing should
* hold locks of all pages in the zspage.
@@ -1819,6 +1878,24 @@ static void lock_zspage(struct zspage *zspage)
}
migrate_read_unlock(zspage);
}
+#endif /* defined(CONFIG_ZPOOL) || defined(CONFIG_COMPACTION) */
+
+#ifdef CONFIG_ZPOOL
+/*
+ * Unlocks all the pages of the zspage.
+ *
+ * pool->lock must be held before this function is called
+ * to prevent the underlying pages from migrating.
+ */
+static void unlock_zspage(struct zspage *zspage)
+{
+ struct page *page = get_first_page(zspage);
+
+ do {
+ unlock_page(page);
+ } while ((page = get_next_page(page)) != NULL);
+}
+#endif /* CONFIG_ZPOOL */
static void migrate_lock_init(struct zspage *zspage)
{
@@ -1835,6 +1912,7 @@ static void migrate_read_unlock(struct zspage *zspage) __releases(&zspage->lock)
read_unlock(&zspage->lock);
}
+#ifdef CONFIG_COMPACTION
static void migrate_write_lock(struct zspage *zspage)
{
write_lock(&zspage->lock);
@@ -2399,6 +2477,100 @@ void zs_destroy_pool(struct zs_pool *pool)
}
EXPORT_SYMBOL_GPL(zs_destroy_pool);
+#ifdef CONFIG_ZPOOL
+static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries)
+{
+ int i, obj_idx, ret = 0;
+ unsigned long handle;
+ struct zspage *zspage;
+ struct page *page;
+ enum fullness_group fullness;
+
+ /* Lock LRU and fullness list */
+ spin_lock(&pool->lock);
+ if (list_empty(&pool->lru)) {
+ spin_unlock(&pool->lock);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < retries; i++) {
+ struct size_class *class;
+
+ zspage = list_last_entry(&pool->lru, struct zspage, lru);
+ list_del(&zspage->lru);
+
+ /* zs_free may free objects, but not the zspage and handles */
+ zspage->under_reclaim = true;
+
+ class = zspage_class(pool, zspage);
+ fullness = get_fullness_group(class, zspage);
+
+ /* Lock out object allocations and object compaction */
+ remove_zspage(class, zspage, fullness);
+
+ spin_unlock(&pool->lock);
+ cond_resched();
+
+ /* Lock backing pages into place */
+ lock_zspage(zspage);
+
+ obj_idx = 0;
+ page = get_first_page(zspage);
+ while (1) {
+ handle = find_alloced_obj(class, page, &obj_idx);
+ if (!handle) {
+ page = get_next_page(page);
+ if (!page)
+ break;
+ obj_idx = 0;
+ continue;
+ }
+
+ /*
+ * This will write the object and call zs_free.
+ *
+ * zs_free will free the object, but the
+ * under_reclaim flag prevents it from freeing
+ * the zspage altogether. This is necessary so
+ * that we can continue working with the
+ * zspage potentially after the last object
+ * has been freed.
+ */
+ ret = pool->zpool_ops->evict(pool->zpool, handle);
+ if (ret)
+ goto next;
+
+ obj_idx++;
+ }
+
+next:
+ /* For freeing the zspage, or putting it back in the pool and LRU list. */
+ spin_lock(&pool->lock);
+ zspage->under_reclaim = false;
+
+ if (!get_zspage_inuse(zspage)) {
+ /*
+ * Fullness went stale as zs_free() won't touch it
+ * while the page is removed from the pool. Fix it
+ * up for the check in __free_zspage().
+ */
+ zspage->fullness = ZS_EMPTY;
+
+ __free_zspage(pool, class, zspage);
+ spin_unlock(&pool->lock);
+ return 0;
+ }
+
+ putback_zspage(class, zspage);
+ list_add(&zspage->lru, &pool->lru);
+ unlock_zspage(zspage);
+ }
+
+ spin_unlock(&pool->lock);
+ return -EAGAIN;
+}
+#endif /* CONFIG_ZPOOL */
+
static int __init zs_init(void)
{
int ret;