+ mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5.patch added to mm-new branch

+ mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5.patch added to mm-new branch

[Andrew Morton]

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The patch titled
     Subject: mm/vmscan: Skip memcg with !usage in shrink_node_memcgs()
has been added to the -mm mm-new branch.  Its filename is
     mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Waiman Long <longman@redhat.com>
Subject: mm/vmscan: Skip memcg with !usage in shrink_node_memcgs()
Date: Mon, 7 Apr 2025 12:23:15 -0400

use mem_cgroup_usage() as originally suggested by Johannes

Link: https://lkml.kernel.org/r/20250407162316.1434714-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/internal.h      |    9 +++++++++
 mm/memcontrol-v1.h |    2 --
 mm/vmscan.c        |    8 +-------
 3 files changed, 10 insertions(+), 9 deletions(-)

--- a/mm/internal.h~mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5
+++ a/mm/internal.h
@@ -1538,6 +1538,15 @@ void __meminit __init_page_from_nid(unsi
 unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg,
 			  int priority);
 
+#ifdef CONFIG_MEMCG
+unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap);
+#else
+static inline unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
+{
+	return 1UL;
+}
+#endif
+
 #ifdef CONFIG_SHRINKER_DEBUG
 static inline __printf(2, 0) int shrinker_debugfs_name_alloc(
 			struct shrinker *shrinker, const char *fmt, va_list ap)
--- a/mm/memcontrol-v1.h~mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5
+++ a/mm/memcontrol-v1.h
@@ -22,8 +22,6 @@
 	     iter != NULL;				\
 	     iter = mem_cgroup_iter(NULL, iter, NULL))
 
-unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap);
-
 void drain_all_stock(struct mem_cgroup *root_memcg);
 
 unsigned long memcg_events(struct mem_cgroup *memcg, int event);
--- a/mm/vmscan.c~mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5
+++ a/mm/vmscan.c
@@ -5934,7 +5934,6 @@ static inline bool should_continue_recla
 	return inactive_lru_pages > pages_for_compaction;
 }
 
-#ifdef CONFIG_MEMCG
 static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
 {
 	struct mem_cgroup *target_memcg = sc->target_mem_cgroup;
@@ -5973,7 +5972,7 @@ static void shrink_node_memcgs(pg_data_t
 		mem_cgroup_calculate_protection(target_memcg, memcg);
 
 		/* Skip memcg with no usage */
-		if (!page_counter_read(&memcg->memory))
+		if (!mem_cgroup_usage(memcg, false))
 			continue;
 
 		if (mem_cgroup_below_min(target_memcg, memcg)) {
@@ -6017,11 +6016,6 @@ static void shrink_node_memcgs(pg_data_t
 		}
 	} while ((memcg = mem_cgroup_iter(target_memcg, memcg, partial)));
 }
-#else
-static inline void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
-{
-}
-#endif /* CONFIG_MEMCG */
 
 static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
 {
_

Patches currently in -mm which might be from longman@redhat.com are

mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs.patch
mm-vmscan-skip-memcg-with-usage-in-shrink_node_memcgs-v5.patch
selftests-memcg-increase-error-tolerance-of-child-memorycurrent-check-in-test_memcg_protection.patch