* + mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch added to mm-new branch
@ 2026-08-28 23:17 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-08-28 23:17 UTC (permalink / raw)
To: mm-commits, ziy, yuzhao, yuanchu, weixugc, vbabka, shakeel.butt,
roman.gushchin, ridong.chen, qi.zheng, muchun.song, mhocko, ljs,
lianux.mm, liam, hannes, david, chrisl, baoquan.he, baolin.wang,
baohua, axelrasmussen, kasong, akpm
The patch titled
Subject: mm/mglru: use explicit tier range in read_ctrl_pos()
has been added to the -mm mm-new branch. Its filename is
mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.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
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: mm/mglru: use explicit tier range in read_ctrl_pos()
Date: Wed, 26 Aug 2026 01:53:38 +0800
read_ctrl_pos() encodes the tier range in a single "tier" parameter via
"tier % MAX_NR_TIERS" as the start and "min(tier, MAX_NR_TIERS-1)" as the
end. This is hard to follow, maintain, or extend. Tier values 0..3
select a single tier, while tier == MAX_NR_TIERS selects the full range.
Replace it with explicit (tier_min, tier_max) parameters using a closed
[tier_min, tier_max] interval, and add LRU_TIER_MIN and LRU_TIER_MAX for
the tier bounds. The call sites now become self-documenting:
- get_tier_idx: (LRU_TIER_MIN, LRU_TIER_MIN) for the first tier,
(tier, tier) for each subsequent tier
- get_type_to_scan: (LRU_TIER_MIN, LRU_TIER_MAX) for the full range
No functional change.
Link: https://lore.kernel.org/20260826-mglru-flags-cleanup-v3-5-d9f1c75549c8@tencent.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Baoquan He <baoquan.he@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lian Wang <lianux.mm@gmail.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Ridong Chen <ridong.chen@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mmzone.h | 2 ++
mm/vmscan.c | 18 ++++++++++--------
2 files changed, 12 insertions(+), 8 deletions(-)
--- a/include/linux/mmzone.h~mm-mglru-use-explicit-tier-range-in-read_ctrl_pos
+++ a/include/linux/mmzone.h
@@ -495,6 +495,8 @@ enum lruvec_flags {
* folio->flags, masked by LRU_REFS_MASK.
*/
#define MAX_NR_TIERS 4U
+#define LRU_TIER_MIN 0U
+#define LRU_TIER_MAX (MAX_NR_TIERS - 1)
#ifndef __GENERATING_BOUNDS_H
--- a/mm/vmscan.c~mm-mglru-use-explicit-tier-range-in-read_ctrl_pos
+++ a/mm/vmscan.c
@@ -3198,8 +3198,8 @@ struct ctrl_pos {
int gain;
};
-static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain,
- struct ctrl_pos *pos)
+static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier_min,
+ int tier_max, int gain, struct ctrl_pos *pos)
{
int i;
struct lru_gen_folio *lrugen = &lruvec->lrugen;
@@ -3208,7 +3208,7 @@ static void read_ctrl_pos(struct lruvec
pos->gain = gain;
pos->refaulted = pos->total = 0;
- for (i = tier % MAX_NR_TIERS; i <= min(tier, MAX_NR_TIERS - 1); i++) {
+ for (i = tier_min; i <= tier_max; i++) {
pos->refaulted += lrugen->avg_refaulted[type][i] +
atomic_long_read(&lrugen->refaulted[hist][type][i]);
pos->total += lrugen->avg_total[type][i] +
@@ -4809,9 +4809,9 @@ static int get_tier_idx(struct lruvec *l
* This value is chosen because any other tier would have at least twice
* as many refaults as the first tier.
*/
- read_ctrl_pos(lruvec, type, 0, 2, &sp);
- for (tier = 1; tier < MAX_NR_TIERS; tier++) {
- read_ctrl_pos(lruvec, type, tier, 3, &pv);
+ read_ctrl_pos(lruvec, type, LRU_TIER_MIN, LRU_TIER_MIN, 2, &sp);
+ for (tier = LRU_TIER_MIN + 1; tier <= LRU_TIER_MAX; tier++) {
+ read_ctrl_pos(lruvec, type, tier, tier, 3, &pv);
if (!positive_ctrl_err(&sp, &pv))
break;
}
@@ -4832,8 +4832,10 @@ static int get_type_to_scan(struct lruve
* Compare the sum of all tiers of anon with that of file to determine
* which type to scan.
*/
- read_ctrl_pos(lruvec, LRU_GEN_ANON, MAX_NR_TIERS, swappiness, &sp);
- read_ctrl_pos(lruvec, LRU_GEN_FILE, MAX_NR_TIERS, MAX_SWAPPINESS - swappiness, &pv);
+ read_ctrl_pos(lruvec, LRU_GEN_ANON, LRU_TIER_MIN, LRU_TIER_MAX,
+ swappiness, &sp);
+ read_ctrl_pos(lruvec, LRU_GEN_FILE, LRU_TIER_MIN, LRU_TIER_MAX,
+ MAX_SWAPPINESS - swappiness, &pv);
return positive_ctrl_err(&sp, &pv);
}
_
Patches currently in -mm which might be from kasong@tencent.com are
mm-memcontrol-make-lru_zone_size-atomic-and-simplify-sanity-check.patch
mm-mglru-introduce-helpers-for-manipulating-gen-and-refs-flags.patch
mm-migrate-copy-all-referenced-state-via-folio_migrate_lru_refs.patch
mm-mglru-move-max_seq-read-into-walk_update_folio.patch
mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch
mm-mglru-fix-potential-generation-folio-number-leak.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* + mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch added to mm-new branch
@ 2026-09-05 22:25 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-09-05 22:25 UTC (permalink / raw)
To: mm-commits, ziy, yuzhao, yuanchu, weixugc, vbabka, shakeel.butt,
ryncsn, roman.gushchin, ridong.chen, qi.zheng, muchun.song,
mhocko, ljs, lianux.mm, liam, hannes, david, chrisl, baoquan.he,
baolin.wang, baohua, axelrasmussen, kasong, akpm
The patch titled
Subject: mm/mglru: use explicit tier range in read_ctrl_pos()
has been added to the -mm mm-new branch. Its filename is
mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.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
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: mm/mglru: use explicit tier range in read_ctrl_pos()
Date: Sun, 06 Sep 2026 00:51:10 +0800
read_ctrl_pos() encodes the tier range in a single "tier" parameter via
"tier % MAX_NR_TIERS" as the start and "min(tier, MAX_NR_TIERS-1)" as the
end. This is hard to follow, maintain, or extend. Tier values 0..3
select a single tier, while tier == MAX_NR_TIERS selects the full range.
Replace it with explicit (tier_min, tier_max) parameters using a closed
[tier_min, tier_max] interval, and add LRU_TIER_MIN and LRU_TIER_MAX for
the tier bounds. The call sites now become self-documenting:
- get_tier_idx: (LRU_TIER_MIN, LRU_TIER_MIN) for the first tier,
(tier, tier) for each subsequent tier
- get_type_to_scan: (LRU_TIER_MIN, LRU_TIER_MAX) for the full range
No functional change.
Link: https://lore.kernel.org/20260906-mglru-flags-cleanup-v6-5-9aacbd77d4ca@tencent.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Baoquan He <baoquan.he@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Ridong Chen <ridong.chen@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lian Wang <lianux.mm@gmail.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mmzone.h | 2 ++
mm/vmscan.c | 18 ++++++++++--------
2 files changed, 12 insertions(+), 8 deletions(-)
--- a/include/linux/mmzone.h~mm-mglru-use-explicit-tier-range-in-read_ctrl_pos
+++ a/include/linux/mmzone.h
@@ -495,6 +495,8 @@ enum lruvec_flags {
* folio->flags, masked by LRU_REFS_MASK.
*/
#define MAX_NR_TIERS 4U
+#define LRU_TIER_MIN 0U
+#define LRU_TIER_MAX (MAX_NR_TIERS - 1)
#ifndef __GENERATING_BOUNDS_H
--- a/mm/vmscan.c~mm-mglru-use-explicit-tier-range-in-read_ctrl_pos
+++ a/mm/vmscan.c
@@ -3223,8 +3223,8 @@ struct ctrl_pos {
int gain;
};
-static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier, int gain,
- struct ctrl_pos *pos)
+static void read_ctrl_pos(struct lruvec *lruvec, int type, int tier_min,
+ int tier_max, int gain, struct ctrl_pos *pos)
{
int i;
struct lru_gen_folio *lrugen = &lruvec->lrugen;
@@ -3233,7 +3233,7 @@ static void read_ctrl_pos(struct lruvec
pos->gain = gain;
pos->refaulted = pos->total = 0;
- for (i = tier % MAX_NR_TIERS; i <= min(tier, MAX_NR_TIERS - 1); i++) {
+ for (i = tier_min; i <= tier_max; i++) {
pos->refaulted += lrugen->avg_refaulted[type][i] +
atomic_long_read(&lrugen->refaulted[hist][type][i]);
pos->total += lrugen->avg_total[type][i] +
@@ -4879,9 +4879,9 @@ static int get_tier_idx(struct lruvec *l
* This value is chosen because any other tier would have at least twice
* as many refaults as the first tier.
*/
- read_ctrl_pos(lruvec, type, 0, 2, &sp);
- for (tier = 1; tier < MAX_NR_TIERS; tier++) {
- read_ctrl_pos(lruvec, type, tier, 3, &pv);
+ read_ctrl_pos(lruvec, type, LRU_TIER_MIN, LRU_TIER_MIN, 2, &sp);
+ for (tier = LRU_TIER_MIN + 1; tier <= LRU_TIER_MAX; tier++) {
+ read_ctrl_pos(lruvec, type, tier, tier, 3, &pv);
if (!positive_ctrl_err(&sp, &pv))
break;
}
@@ -4902,8 +4902,10 @@ static int get_type_to_scan(struct lruve
* Compare the sum of all tiers of anon with that of file to determine
* which type to scan.
*/
- read_ctrl_pos(lruvec, LRU_GEN_ANON, MAX_NR_TIERS, swappiness, &sp);
- read_ctrl_pos(lruvec, LRU_GEN_FILE, MAX_NR_TIERS, MAX_SWAPPINESS - swappiness, &pv);
+ read_ctrl_pos(lruvec, LRU_GEN_ANON, LRU_TIER_MIN, LRU_TIER_MAX,
+ swappiness, &sp);
+ read_ctrl_pos(lruvec, LRU_GEN_FILE, LRU_TIER_MIN, LRU_TIER_MAX,
+ MAX_SWAPPINESS - swappiness, &pv);
return positive_ctrl_err(&sp, &pv);
}
_
Patches currently in -mm which might be from kasong@tencent.com are
mm-memcontrol-move-the-lru_zone_size-sanity-check-to-the-reader-side.patch
mm-mglru-introduce-helpers-for-manipulating-gen-and-refs-flags.patch
mm-migrate-copy-all-referenced-state-via-folio_migrate_lru_refs.patch
mm-mglru-move-max_seq-read-into-walk_update_folio.patch
mm-mglru-use-explicit-tier-range-in-read_ctrl_pos.patch
mm-mglru-fix-potential-generation-folio-number-leak.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
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