+ mm-mglru-extract-lruvec_populated_min_seq-helper.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/mglru: extract lruvec_populated_min_seq() helper
has been added to the -mm mm-new branch.  Its filename is
     mm-mglru-extract-lruvec_populated_min_seq-helper.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-extract-lruvec_populated_min_seq-helper.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: Kairui Song <kasong@tencent.com>
Subject: mm/mglru: extract lruvec_populated_min_seq() helper
Date: Sat, 14 Nov 2026 02:55:27 +0800

The search for the oldest populated generation of a type, previously
embedded in try_to_inc_min_seq(), is extracted into the new
lruvec_populated_min_seq() helper. It returns the oldest populated seq
of a given type, bounded by the given max_seq so the search never goes
beyond it.

No functional change.

Link: https://lore.kernel.org/20261113185541.70203-3-baohua@kernel.org
Signed-off-by: Kairui Song <kasong@tencent.com>
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <hui.zhu@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: wang lian <lianux.mm@gmail.com>
Cc: <liuxiang.277@bytedance.com>
Cc: <lyugaofei@xiaomi.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Ridong Chen <ridong.chen@linux.dev>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: wangzicheng <wangzicheng@honor.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Bo Zhang <zhangbo56@xiaomi.com>
Cc: Hui Zhu <zhuhui@kylinos.cn>
Cc: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
Cc: Kunwu Chan <chentao@kylinos.cn>
Cc: Bo Zhang <zhangbo0325@gmail.com>
---

 mm/vmscan.c |   45 +++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

--- a/mm/vmscan.c~mm-mglru-extract-lruvec_populated_min_seq-helper
+++ a/mm/vmscan.c
@@ -3992,30 +3992,45 @@ done:
 	return true;
 }
 
+/* Similar to lruvec_evictable_size, return the oldest populated seq of the type */
+static unsigned long lruvec_populated_min_seq(struct lruvec *lruvec, int type,
+					      unsigned long max_seq)
+{
+	int gen, zone;
+	unsigned long min_seq;
+	struct lru_gen_folio *lrugen = &lruvec->lrugen;
+
+	lockdep_assert_held(&lruvec->lru_lock);
+
+	min_seq = READ_ONCE(lrugen->min_seq[type]);
+	while (min_seq <= max_seq) {
+		gen = lru_gen_from_seq(min_seq);
+		for (zone = 0; zone < MAX_NR_ZONES; zone++) {
+			if (!list_empty(&lrugen->folios[gen][type][zone]))
+				return min_seq;
+		}
+		min_seq++;
+	}
+
+	return max_seq;
+}
+
 static void try_to_inc_min_seq(struct lruvec *lruvec, int swappiness)
 {
-	int gen, type, zone;
+	int type;
 	bool seq_inc_flag = false;
 	struct lru_gen_folio *lrugen = &lruvec->lrugen;
 	DEFINE_MIN_SEQ(lruvec);
+	unsigned long seq;
 
 	VM_WARN_ON_ONCE(!seq_is_valid(lruvec));
 
-	/* find the oldest populated generation */
+	/* Requires at least MIN_NR_GENS gens for basic functionality */
+	seq = lrugen->max_seq - MIN_NR_GENS;
 	for_each_evictable_type(type, swappiness) {
-		while (min_seq[type] + MIN_NR_GENS <= lrugen->max_seq) {
-			gen = lru_gen_from_seq(min_seq[type]);
-
-			for (zone = 0; zone < MAX_NR_ZONES; zone++) {
-				if (!list_empty(&lrugen->folios[gen][type][zone]))
-					goto next;
-			}
-
-			min_seq[type]++;
+		min_seq[type] = lruvec_populated_min_seq(lruvec, type, seq + 1);
+		if (min_seq[type] > lrugen->min_seq[type])
 			seq_inc_flag = true;
-		}
-next:
-		;
 	}
 
 	/*
@@ -4027,8 +4042,6 @@ next:
 
 	/* see the comment on lru_gen_folio */
 	if (swappiness && swappiness <= MAX_SWAPPINESS) {
-		unsigned long seq = lrugen->max_seq - MIN_NR_GENS;
-
 		if (min_seq[LRU_GEN_ANON] > seq && min_seq[LRU_GEN_FILE] < seq)
 			min_seq[LRU_GEN_ANON] = seq;
 		else if (min_seq[LRU_GEN_FILE] > seq && min_seq[LRU_GEN_ANON] < seq)
_

Patches currently in -mm which might be from kasong@tencent.com are

mm-mglru-report-evictable-sizes-per-type.patch
mm-mglru-extract-lruvec_populated_min_seq-helper.patch
mm-mglru-reclaim-from-the-oldest-populated-gen.patch
mm-mglru-lift-the-forced-protection-of-reclaimer.patch
mm-mglru-skip-zones-above-reclaim_idx-instead-of-rotating-them.patch
mm-mglru-return-for-unavailable-anon-reclaim-earlier.patch
mm-mglru-balance-anon-and-file-scan-budget-by-refault-rate.patch
mm-mglru-lift-youngest-gen-protection-for-higher-priority.patch