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From: Yang Shi <shy828301@gmail.com>
To: guro@fb.com, ktkhai@virtuozzo.com, vbabka@suse.cz,
	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: [v7 PATCH 06/12] mm: vmscan: add shrinker_info_protected() helper
Date: Tue,  9 Feb 2021 09:46:40 -0800	[thread overview]
Message-ID: <20210209174646.1310591-7-shy828301@gmail.com> (raw)
In-Reply-To: <20210209174646.1310591-1-shy828301@gmail.com>

The shrinker_info is dereferenced in a couple of places via rcu_dereference_protected
with different calling conventions, for example, using mem_cgroup_nodeinfo helper
or dereferencing memcg->nodeinfo[nid]->shrinker_info.  And the later patch
will add more dereference places.

So extract the dereference into a helper to make the code more readable.  No
functional change.

Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 mm/vmscan.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9436f9246d32..273efbf4d53c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -190,6 +190,13 @@ static int shrinker_nr_max;
 #define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
 	(DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))
 
+static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
+						     int nid)
+{
+	return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
+					 lockdep_is_held(&shrinker_rwsem));
+}
+
 static void free_shrinker_info_rcu(struct rcu_head *head)
 {
 	kvfree(container_of(head, struct shrinker_info, rcu));
@@ -202,8 +209,7 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg,
 	int nid;
 
 	for_each_node(nid) {
-		old = rcu_dereference_protected(
-			mem_cgroup_nodeinfo(memcg, nid)->shrinker_info, true);
+		old = shrinker_info_protected(memcg, nid);
 		/* Not yet online memcg */
 		if (!old)
 			return 0;
@@ -234,7 +240,7 @@ void free_shrinker_info(struct mem_cgroup *memcg)
 
 	for_each_node(nid) {
 		pn = mem_cgroup_nodeinfo(memcg, nid);
-		info = rcu_dereference_protected(pn->shrinker_info, true);
+		info = shrinker_info_protected(memcg, nid);
 		kvfree(info);
 		rcu_assign_pointer(pn->shrinker_info, NULL);
 	}
@@ -674,8 +680,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
 	if (!down_read_trylock(&shrinker_rwsem))
 		return 0;
 
-	info = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
-					 true);
+	info = shrinker_info_protected(memcg, nid);
 	if (unlikely(!info))
 		goto unlock;
 
-- 
2.26.2


  parent reply	other threads:[~2021-02-09 18:23 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-09 17:46 [v7 PATCH 0/12] Make shrinker's nr_deferred memcg aware Yang Shi
2021-02-09 17:46 ` [v7 PATCH 01/12] mm: vmscan: use nid from shrink_control for tracepoint Yang Shi
2021-02-09 19:14   ` Shakeel Butt
2021-02-10 16:58     ` Yang Shi
2021-02-09 19:21   ` Roman Gushchin
2021-02-09 17:46 ` [v7 PATCH 02/12] mm: vmscan: consolidate shrinker_maps handling code Yang Shi
2021-02-09 20:27   ` Roman Gushchin
2021-02-10 14:19   ` Shakeel Butt
2021-02-09 17:46 ` [v7 PATCH 03/12] mm: vmscan: use shrinker_rwsem to protect shrinker_maps allocation Yang Shi
2021-02-09 20:33   ` Roman Gushchin
2021-02-09 23:28     ` Yang Shi
2021-02-09 17:46 ` [v7 PATCH 04/12] mm: vmscan: remove memcg_shrinker_map_size Yang Shi
2021-02-09 20:43   ` Roman Gushchin
2021-02-09 23:31     ` Yang Shi
2021-02-10 18:14     ` Vlastimil Babka
2021-02-09 17:46 ` [v7 PATCH 05/12] mm: memcontrol: rename shrinker_map to shrinker_info Yang Shi
2021-02-09 20:50   ` Roman Gushchin
2021-02-09 23:33     ` Yang Shi
2021-02-10  0:16       ` Roman Gushchin
2021-02-11 16:47       ` Kirill Tkhai
2021-02-11 17:29         ` Yang Shi
2021-02-09 17:46 ` Yang Shi [this message]
2021-02-10  0:22   ` [v7 PATCH 06/12] mm: vmscan: add shrinker_info_protected() helper Roman Gushchin
2021-02-10  1:07     ` Yang Shi
2021-02-10  1:29       ` Roman Gushchin
2021-02-10 12:12   ` Kirill Tkhai
2021-02-10 18:17   ` Vlastimil Babka
2021-02-12  6:54   ` [mm] bd741fb2ad: WARNING:suspicious_RCU_usage kernel test robot
2021-02-09 17:46 ` [v7 PATCH 07/12] mm: vmscan: use a new flag to indicate shrinker is registered Yang Shi
2021-02-10  0:39   ` Roman Gushchin
2021-02-10  1:12     ` Yang Shi
2021-02-10  1:34       ` Roman Gushchin
2021-02-10  1:55         ` Yang Shi
2021-02-10 18:45     ` Yang Shi
2021-02-10 18:23   ` Vlastimil Babka
2021-02-09 17:46 ` [v7 PATCH 08/12] mm: vmscan: add per memcg shrinker nr_deferred Yang Shi
2021-02-10  1:10   ` Roman Gushchin
2021-02-10  1:25     ` Yang Shi
2021-02-10  1:40       ` Roman Gushchin
2021-02-10  1:57         ` Yang Shi
2021-02-09 17:46 ` [v7 PATCH 09/12] mm: vmscan: use per memcg nr_deferred of shrinker Yang Shi
2021-02-10  1:27   ` Roman Gushchin
2021-02-10  1:52     ` Yang Shi
2021-02-10 14:36       ` Kirill Tkhai
2021-02-10 16:41         ` Yang Shi
2021-02-09 17:46 ` [v7 PATCH 10/12] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers Yang Shi
2021-02-10  1:23   ` Roman Gushchin
2021-02-09 17:46 ` [v7 PATCH 11/12] mm: memcontrol: reparent nr_deferred when memcg offline Yang Shi
2021-02-10  1:18   ` Roman Gushchin
2021-02-09 17:46 ` [v7 PATCH 12/12] mm: vmscan: shrink deferred objects proportional to priority Yang Shi
2021-02-11 13:10   ` Vlastimil Babka
2021-02-11 17:29     ` Yang Shi
2021-02-11 18:52       ` Vlastimil Babka
2021-02-11 19:15         ` Yang Shi

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