+ mm-using-swappiness_anon_only-in-mglru.patch added to mm-new branch

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

The patch titled
     Subject: mm: use SWAPPINESS_ANON_ONLY in MGLRU
has been added to the -mm mm-new branch.  Its filename is
     mm-using-swappiness_anon_only-in-mglru.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-using-swappiness_anon_only-in-mglru.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.

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------------------------------------------------------
From: Zhongkun He <hezhongkun.hzk@bytedance.com>
Subject: mm: use SWAPPINESS_ANON_ONLY in MGLRU
Date: Mon, 21 Apr 2025 17:13:31 +0800

Using SWAPPINESS_ANON_ONLY instead of MAX_SWAPPINESS + 1 to indicate
reclaiming only from anonymous pages makes the code more readable and
explicit.

Add some comment in the SWAPPINESS_ANON_ONLY context.

Link: https://lkml.kernel.org/r/529db7ae6098ee712b81e4df290622e4e64ac50c.1745225696.git.hezhongkun.hzk@bytedance.com
Signed-off-by: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmscan.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

--- a/mm/vmscan.c~mm-using-swappiness_anon_only-in-mglru
+++ a/mm/vmscan.c
@@ -2699,8 +2699,12 @@ static bool should_clear_pmd_young(void)
 		READ_ONCE((lruvec)->lrugen.min_seq[LRU_GEN_FILE]),	\
 	}
 
+/* Get the min/max evictable type based on swappiness */
+#define min_type(swappiness) (!(swappiness))
+#define max_type(swappiness) ((swappiness) < SWAPPINESS_ANON_ONLY)
+
 #define evictable_min_seq(min_seq, swappiness)				\
-	min((min_seq)[!(swappiness)], (min_seq)[(swappiness) <= MAX_SWAPPINESS])
+	min((min_seq)[min_type(swappiness)], (min_seq)[max_type(swappiness)])
 
 #define for_each_gen_type_zone(gen, type, zone)				\
 	for ((gen) = 0; (gen) < MAX_NR_GENS; (gen)++)			\
@@ -2708,7 +2712,7 @@ static bool should_clear_pmd_young(void)
 			for ((zone) = 0; (zone) < MAX_NR_ZONES; (zone)++)
 
 #define for_each_evictable_type(type, swappiness)			\
-	for ((type) = !(swappiness); (type) <= ((swappiness) <= MAX_SWAPPINESS); (type)++)
+	for ((type) = min_type(swappiness); (type) <= max_type(swappiness); (type)++)
 
 #define get_memcg_gen(seq)	((seq) % MEMCG_NR_GENS)
 #define get_memcg_bin(bin)	((bin) % MEMCG_NR_BINS)
@@ -3859,7 +3863,12 @@ static bool inc_min_seq(struct lruvec *l
 	int hist = lru_hist_from_seq(lrugen->min_seq[type]);
 	int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]);
 
-	if (type ? swappiness > MAX_SWAPPINESS : !swappiness)
+	/* For file type, skip the check if swappiness is anon only */
+	if (type && (swappiness == SWAPPINESS_ANON_ONLY))
+		goto done;
+
+	/* For anon type, skip the check if swappiness is zero (file only) */
+	if (!type && !swappiness)
 		goto done;
 
 	/* prevent cold/hot inversion if the type is evictable */
@@ -5530,7 +5539,7 @@ static int run_cmd(char cmd, int memcg_i
 
 	if (swappiness < MIN_SWAPPINESS)
 		swappiness = get_swappiness(lruvec, sc);
-	else if (swappiness > MAX_SWAPPINESS + 1)
+	else if (swappiness > SWAPPINESS_ANON_ONLY)
 		goto done;
 
 	switch (cmd) {
_

Patches currently in -mm which might be from hezhongkun.hzk@bytedance.com are

mm-add-swappiness=max-arg-to-memoryreclaim-for-only-anon-reclaim.patch
mm-vmscan-add-more-comments-about-cache_trim_mode.patch
mm-add-max-swappiness-arg-to-lru_gen-for-anonymous-memory-only.patch
mm-using-swappiness_anon_only-in-mglru.patch