[RFC][PATCH v3 2/5] mm/zsmalloc: remove shrinker compaction callbacks

[Sergey Senozhatsky]

Do not register shrinker compaction callbacks anymore, since
now we shedule class compaction work each time its fragmentation
value goes above the watermark.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
 mm/zsmalloc.c | 72 -----------------------------------------------------------
 1 file changed, 72 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index a4ef7e7..0bb060f 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -256,13 +256,6 @@ struct zs_pool {
 
 	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
@@ -1848,64 +1841,6 @@ void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats)
 }
 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);
-
-	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
@@ -1994,12 +1929,6 @@ struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
 	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:
@@ -2012,7 +1941,6 @@ void zs_destroy_pool(struct zs_pool *pool)
 {
 	int i;
 
-	zs_unregister_shrinker(pool);
 	zs_pool_stat_destroy(pool);
 
 	for (i = 0; i < zs_size_classes; i++) {
-- 
2.8.0.rc0