+ mm-vmscan-fix-missing-nr_isolated-counter-update-in-mglru-reclaim-path.patch added to mm-unstable branch

+ mm-vmscan-fix-missing-nr_isolated-counter-update-in-mglru-reclaim-path.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/vmscan: fix missing NR_ISOLATED counter update in MGLRU reclaim path
has been added to the -mm mm-unstable branch.  Its filename is
     mm-vmscan-fix-missing-nr_isolated-counter-update-in-mglru-reclaim-path.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-fix-missing-nr_isolated-counter-update-in-mglru-reclaim-path.patch

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

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------------------------------------------------------
From: Hui Zhu <zhuhui@kylinos.cn>
Subject: mm/vmscan: fix missing NR_ISOLATED counter update in MGLRU reclaim path
Date: Wed, 14 Oct 2026 17:00:23 +0800

MGLRU evict_folios() isolates folios from the LRU without updating the
NR_ISOLATED_ANON/FILE counters, unlike the legacy shrink_inactive_list()
path.  This causes compaction's too_many_isolated() check to under-count
isolated pages when MGLRU reclaim is active.

Add NR_ISOLATED counter updates in evict_folios(): increment after
isolate_folios() and decrement after all retry passes complete, using the
existing nr_isolated which holds the original isolated count.

Link: https://lore.kernel.org/141901355a7d9e4bbca5c4840ae32ea5c65fe3b6.1791968227.git.zhuhui@kylinos.cn
Link: https://lore.kernel.org/cover.1791968227.git.zhuhui@kylinos.cn
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
---

 mm/vmscan.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/mm/vmscan.c~mm-vmscan-fix-missing-nr_isolated-counter-update-in-mglru-reclaim-path
+++ a/mm/vmscan.c
@@ -5081,6 +5081,9 @@ static int evict_folios(unsigned long nr
 	scanned = isolate_folios(nr_to_scan, lruvec, sc, swappiness,
 				 &list, &isolated, &type, &type_scanned);
 	nr_isolated = isolated;
+	if (nr_isolated)
+		__mod_node_page_state(pgdat, NR_ISOLATED_ANON + type,
+				      nr_isolated);
 
 	/* Scanning may have emptied the oldest gen, flush it */
 	if (scanned)
@@ -5149,6 +5152,8 @@ retry:
 		goto retry;
 	}
 
+	mod_node_page_state(pgdat, NR_ISOLATED_ANON + type, -nr_isolated);
+
 	if (nr_isolated > total_reclaimed)
 		mod_lruvec_state(lruvec, PGROTATE_ANON + type,
 				 nr_isolated - total_reclaimed);
_

Patches currently in -mm which might be from zhuhui@kylinos.cn are

mm-vmscan-fix-missing-nr_isolated-counter-update-in-mglru-reclaim-path.patch