+ mm-vmscan-drop-the-combined-limit-gate-in-__node_reclaim.patch added to mm-new branch

+ mm-vmscan-drop-the-combined-limit-gate-in-__node_reclaim.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/vmscan: drop the combined limit gate in __node_reclaim()
has been added to the -mm mm-new branch.  Its filename is
     mm-vmscan-drop-the-combined-limit-gate-in-__node_reclaim.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-drop-the-combined-limit-gate-in-__node_reclaim.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Ridong Chen <chenridong@xiaomi.com>
Subject: mm/vmscan: drop the combined limit gate in __node_reclaim()
Date: Wed, 26 Aug 2026 20:44:09 +0800

__node_reclaim() is called from two paths: node_reclaim() and
user_proactive_reclaim().

node_reclaim() already bails out early unless node_pagecache_reclaimable()
is over pgdat->min_unmapped_pages or the reclaimable slab is over
pgdat->min_slab_pages.  The identical check inside __node_reclaim() that
guards the shrink_node() loop is therefore redundant for this path.

user_proactive_reclaim() is proactive reclaim driven by userspace and
should not be gated by the per-node min_unmapped_pages / min_slab_pages
limits at all [1].  With the gate in place, a proactive request is
silently turned into a no-op whenever the node happens to sit below both
thresholds.

Drop the gate in __node_reclaim() and always run the shrink_node() loop. 
The node_reclaim() path is unchanged, since its caller has already applied
the same test; the proactive path is no longer wrongly gated.

Link: https://lore.kernel.org/20260826124409.35569-1-ridong.chen@linux.dev
Link: https://sashiko.dev/#/patchset/20260723045718.2052070-1-ridong.chen@linux.dev [1]
Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface")
Assisted-by: Claude:claude-opus-4-8
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kairui Song <kasong@tencent.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmscan.c |   13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

--- a/mm/vmscan.c~mm-vmscan-drop-the-combined-limit-gate-in-__node_reclaim
+++ a/mm/vmscan.c
@@ -7851,16 +7851,9 @@ static unsigned long __node_reclaim(stru
 	noreclaim_flag = memalloc_noreclaim_save();
 	set_task_reclaim_state(p, &sc->reclaim_state);
 
-	if (node_pagecache_reclaimable(pgdat) > pgdat->min_unmapped_pages ||
-	    node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B) > pgdat->min_slab_pages) {
-		/*
-		 * Free memory by calling shrink node with increasing
-		 * priorities until we have enough memory freed.
-		 */
-		do {
-			shrink_node(pgdat, sc);
-		} while (sc->nr_reclaimed < nr_pages && --sc->priority >= 0);
-	}
+	do {
+		shrink_node(pgdat, sc);
+	} while (sc->nr_reclaimed < nr_pages && --sc->priority >= 0);
 
 	set_task_reclaim_state(p, NULL);
 	memalloc_noreclaim_restore(noreclaim_flag);
_

Patches currently in -mm which might be from chenridong@xiaomi.com are

mm-vmscan-drop-the-combined-limit-gate-in-__node_reclaim.patch