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From:   Yang Shi <shy828301@gmail.com>
To:     guro@fb.com, ktkhai@virtuozzo.com, shakeelb@google.com,
        david@fromorbit.com, hannes@cmpxchg.org, mhocko@suse.com,
        akpm@linux-foundation.org
Cc:     shy828301@gmail.com, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 7/9] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers
Date:   Wed,  2 Dec 2020 10:27:23 -0800
Message-Id: <20201202182725.265020-8-shy828301@gmail.com>
In-Reply-To: <20201202182725.265020-1-shy828301@gmail.com>
References: <20201202182725.265020-1-shy828301@gmail.com>
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Now nr_deferred is available on per memcg level for memcg aware shrinkers, so don't need
allocate shrinker->nr_deferred for such shrinkers anymore.

Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 mm/vmscan.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index d569fdcaba79..5fd57060fafd 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -420,7 +420,15 @@ unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone
  */
 int prealloc_shrinker(struct shrinker *shrinker)
 {
-	unsigned int size = sizeof(*shrinker->nr_deferred);
+	unsigned int size;
+
+	if (is_deferred_memcg_aware(shrinker)) {
+		if (prealloc_memcg_shrinker(shrinker))
+			return -ENOMEM;
+		return 0;
+	}
+
+	size = sizeof(*shrinker->nr_deferred);
 
 	if (shrinker->flags & SHRINKER_NUMA_AWARE)
 		size *= nr_node_ids;
@@ -429,26 +437,18 @@ int prealloc_shrinker(struct shrinker *shrinker)
 	if (!shrinker->nr_deferred)
 		return -ENOMEM;
 
-	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
-		if (prealloc_memcg_shrinker(shrinker))
-			goto free_deferred;
-	}
-
 	return 0;
-
-free_deferred:
-	kfree(shrinker->nr_deferred);
-	shrinker->nr_deferred = NULL;
-	return -ENOMEM;
 }
 
 void free_prealloced_shrinker(struct shrinker *shrinker)
 {
-	if (!shrinker->nr_deferred)
+	if (is_deferred_memcg_aware(shrinker)) {
+		unregister_memcg_shrinker(shrinker);
 		return;
+	}
 
-	if (shrinker->flags & SHRINKER_MEMCG_AWARE)
-		unregister_memcg_shrinker(shrinker);
+	if (!shrinker->nr_deferred)
+		return;
 
 	kfree(shrinker->nr_deferred);
 	shrinker->nr_deferred = NULL;
-- 
2.26.2