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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: [v10 PATCH 07/13] mm: vmscan: add shrinker_info_protected() helper
Date: Thu, 11 Mar 2021 11:08:39 -0800	[thread overview]
Message-ID: <20210311190845.9708-8-shy828301@gmail.com> (raw)
In-Reply-To: <20210311190845.9708-1-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.

Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 mm/vmscan.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7fdfdacf9a1f..ef9f1531a6ee 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -192,6 +192,13 @@ static inline int shrinker_map_size(int nr_items)
 	return (DIV_ROUND_UP(nr_items, 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 int expand_one_shrinker_info(struct mem_cgroup *memcg,
 				    int size, int old_size)
 {
@@ -201,7 +208,7 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg,
 
 	for_each_node(nid) {
 		pn = memcg->nodeinfo[nid];
-		old = rcu_dereference_protected(pn->shrinker_info, true);
+		old = shrinker_info_protected(memcg, nid);
 		/* Not yet online memcg */
 		if (!old)
 			return 0;
@@ -232,7 +239,7 @@ void free_shrinker_info(struct mem_cgroup *memcg)
 
 	for_each_node(nid) {
 		pn = memcg->nodeinfo[nid];
-		info = rcu_dereference_protected(pn->shrinker_info, true);
+		info = shrinker_info_protected(memcg, nid);
 		kvfree(info);
 		rcu_assign_pointer(pn->shrinker_info, NULL);
 	}
@@ -675,8 +682,7 @@ 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:[~2021-03-11 19:10 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-11 19:08 [v10 PATCH 00/13] Make shrinker's nr_deferred memcg aware Yang Shi
2021-03-11 19:08 ` [v10 PATCH 01/13] mm: vmscan: use nid from shrink_control for tracepoint Yang Shi
2021-03-11 19:08 ` [v10 PATCH 02/13] mm: vmscan: consolidate shrinker_maps handling code Yang Shi
2021-03-11 19:08 ` [v10 PATCH 03/13] mm: vmscan: use shrinker_rwsem to protect shrinker_maps allocation Yang Shi
2021-03-11 19:08 ` [v10 PATCH 04/13] mm: vmscan: remove memcg_shrinker_map_size Yang Shi
2021-03-11 19:08 ` [v10 PATCH 05/13] mm: vmscan: use kvfree_rcu instead of call_rcu Yang Shi
2021-03-11 19:08 ` [v10 PATCH 06/13] mm: memcontrol: rename shrinker_map to shrinker_info Yang Shi
2021-03-11 19:08 ` Yang Shi [this message]
2021-03-11 19:08 ` [v10 PATCH 08/13] mm: vmscan: use a new flag to indicate shrinker is registered Yang Shi
2021-03-11 19:08 ` [v10 PATCH 09/13] mm: vmscan: add per memcg shrinker nr_deferred Yang Shi
2021-03-11 19:08 ` [v10 PATCH 10/13] mm: vmscan: use per memcg nr_deferred of shrinker Yang Shi
2021-03-11 19:08 ` [v10 PATCH 11/13] mm: vmscan: don't need allocate shrinker->nr_deferred for memcg aware shrinkers Yang Shi
2021-03-11 19:08 ` [v10 PATCH 12/13] mm: memcontrol: reparent nr_deferred when memcg offline Yang Shi
2021-03-11 19:08 ` [v10 PATCH 13/13] mm: vmscan: shrink deferred objects proportional to priority Yang Shi

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