kernel: Update MGLRU patchset

The current patches are old, update them from mainline.
Backports taken from https://github.com/yuzhaogoogle/linux/commits/mglru-5.15

Tested-by: Kazuki H <kazukih0205@gmail.com> #mt7622/Linksys E8450 UBI
Signed-off-by: Kazuki H <kazukih0205@gmail.com>

1 files changed, 93 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.15/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch b/target/linux/generic/backport-5.15/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch
new file mode 100644
index 0000000000..14e1aff177
--- /dev/null
+++ b/target/linux/generic/backport-5.15/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch
@@ -0,0 +1,93 @@
+From cc67f962cc53f6e1dfa92eb85b7b26fe83a3c66f Mon Sep 17 00:00:00 2001
+From: Yu Zhao <yuzhao@google.com>
+Date: Mon, 13 Feb 2023 00:53:22 -0700
+Subject: [PATCH 29/29] mm: multi-gen LRU: avoid futile retries
+
+Recall that the per-node memcg LRU has two generations and they alternate
+when the last memcg (of a given node) is moved from one to the other.
+Each generation is also sharded into multiple bins to improve scalability.
+A reclaimer starts with a random bin (in the old generation) and, if it
+fails, it will retry, i.e., to try the rest of the bins.
+
+If a reclaimer fails with the last memcg, it should move this memcg to the
+young generation first, which causes the generations to alternate, and
+then retry.  Otherwise, the retries will be futile because all other bins
+are empty.
+
+Link: https://lkml.kernel.org/r/20230213075322.1416966-1-yuzhao@google.com
+Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
+Signed-off-by: Yu Zhao <yuzhao@google.com>
+Reported-by: T.J. Mercier <tjmercier@google.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+---
+ mm/vmscan.c | 25 +++++++++++++++----------
+ 1 file changed, 15 insertions(+), 10 deletions(-)
+
+diff --git a/mm/vmscan.c b/mm/vmscan.c
+index 3f6874a69886..0b76774963ff 100644
+--- a/mm/vmscan.c
++++ b/mm/vmscan.c
+@@ -4934,18 +4934,20 @@ static int shrink_one(struct lruvec *lruvec, struct scan_control *sc)
+ 
+ static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc)
+ {
++	int op;
+ 	int gen;
+ 	int bin;
+ 	int first_bin;
+ 	struct lruvec *lruvec;
+ 	struct lru_gen_page *lrugen;
++	struct mem_cgroup *memcg;
+ 	const struct hlist_nulls_node *pos;
+-	int op = 0;
+-	struct mem_cgroup *memcg = NULL;
+ 	unsigned long nr_to_reclaim = get_nr_to_reclaim(sc);
+ 
+ 	bin = first_bin = prandom_u32_max(MEMCG_NR_BINS);
+ restart:
++	op = 0;
++	memcg = NULL;
+ 	gen = get_memcg_gen(READ_ONCE(pgdat->memcg_lru.seq));
+ 
+ 	rcu_read_lock();
+@@ -4969,14 +4971,22 @@ static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc)
+ 
+ 		op = shrink_one(lruvec, sc);
+ 
+-		if (sc->nr_reclaimed >= nr_to_reclaim)
+-			goto success;
+-
+ 		rcu_read_lock();
++
++		if (sc->nr_reclaimed >= nr_to_reclaim)
++			break;
+ 	}
+ 
+ 	rcu_read_unlock();
+ 
++	if (op)
++		lru_gen_rotate_memcg(lruvec, op);
++
++	mem_cgroup_put(memcg);
++
++	if (sc->nr_reclaimed >= nr_to_reclaim)
++		return;
++
+ 	/* restart if raced with lru_gen_rotate_memcg() */
+ 	if (gen != get_nulls_value(pos))
+ 		goto restart;
+@@ -4985,11 +4995,6 @@ static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc)
+ 	bin = get_memcg_bin(bin + 1);
+ 	if (bin != first_bin)
+ 		goto restart;
+-success:
+-	if (op)
+-		lru_gen_rotate_memcg(lruvec, op);
+-
+-	mem_cgroup_put(memcg);
+ }
+ 
+ static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc)
+-- 
+2.40.0
+