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Howlett" , Vlastimil Babka , Ridong Chen , Lian Wang , Yu Zhao , Zi Yan , Qi Zheng , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Kairui Song , Kairui Song X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1788115415; l=3649; i=kasong@tencent.com; s=kasong-sign-tencent; h=from:subject:message-id; bh=CWUxj/CQQzace6S+QxkJDRIrrH9jLNHsJ/crVKhgGbE=; b=FWk6b2RXyde5JYnHfKQSebvOwDlcdZYu+ics5x8yBjnEv1DTOr+mk6s0Kzs0JEfJnGmLmyVXE uFunTQEq+OtBL0CXaykFAju+MmG5A7LoemlTcpVRJVx4ydEfxRGhC4J X-Developer-Key: i=kasong@tencent.com; a=ed25519; pk=kCdoBuwrYph+KrkJnrr7Sm1pwwhGDdZKcKrqiK8Y1mI= X-Endpoint-Received: by B4 Relay for kasong@tencent.com/kasong-sign-tencent with auth_id=562 X-Original-From: Kairui Song Reply-To: kasong@tencent.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 6AD0A14000A X-Stat-Signature: nhiocp586rro6htd3a9xfq9fsrj4f4ah X-HE-Tag: 1788115421-911427 X-HE-Meta: U2FsdGVkX18JvzK1XF/nYzvUJb9+NQJQVKo4s9Xh8PolnbjE8EXmfmuMKcRzU06sAnT+Kr+GZipr/Wifw1sgtPahmQLUTlUV1foPsd9FKwlK3m9Ox5KZ7yd5OebQ9xFvaf2SsA/vR6WVRN5u2YbBOczE5ilET59c5GVxMxI27eHft1pDJs0O/Dwco5qs0/VMQpErg+YtAtcgVYH0A9b84IE7dY6xxB2y0vTyv4zr4nmyQizAK8N1o/U7dD6XyP6QOzkURyXPltFPb2ygzVJ6WFgWHfZiyPBAglXYwT5h70AVXDqxpSzMY0/Ll4NMGBULbU4Gkq0p97llBChc8me8cgu5vuuwNb9X4JvdjRoju8KWM1IrKzRqAHm+Ik7vieADJIwPgP+hzmtABElCmVNU70jyrLNiw4NCYu70W/srRFI13axN8pXWy74ubcPtbAUYhvtiBjxIqG0E4IuQ6qeenVUarLMsdaVHyFxK9xfMRv0BcxekJ+gIUhUsbcje2ocg09+o7tQXs5j7Nhv8rdAh6D9iNBO/scWHeCDpwCwlOs+yjOp3jSxjbfmZ3VsdZcsoBJtIqgBFd4Aq1kcT7pJ0ONEWrArTWhmKAplahCPcWsKB+V/u2J0WDOWy2MtDgZt3Q+nnvYvCG3m0zOfb/J1qSbMTyLNFsIqBKQ8rxatcpKgjvnimpUWrbAZWDYUnquUO+GPgztH4xpYc0CGkPm/96a/UqrFkCIRvo72O6fTE/jiH0gTc7HjIhhfGrjjHVrZoxuC0X8Baj4RuXF19ddvnG3aOnrDXGoYqqWY+q10NvZkrG6dZUP3vQHmpn6uju2YjYEz+vaQRKaDninBZXu5FYWn5bqOV7KO9hMRY91uEUfDkzPCA+zA12Lb55tf2HF2xEx4a3oMJwQrYVra1sjFNSLojpLFwpXmF4sOY6MXrihEYmP6YHnvmw8aWrF/4tl4BLmXzxYQgoq/t77VHPPg yH71zt4h 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Kairui Song 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. Reviewed-by: Baolin Wang Reviewed-by: Baoquan He Reviewed-by: Barry Song Reviewed-by: Ridong Chen Signed-off-by: Kairui Song --- include/linux/mmzone.h | 2 ++ mm/vmscan.c | 18 ++++++++++-------- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c9ecf370cd9f..9b27cf53bdbc 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -492,6 +492,8 @@ 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 diff --git a/mm/vmscan.c b/mm/vmscan.c index 88474d4af54b..724b6e034e69 100644 --- a/mm/vmscan.c +++ b/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 *lruvec, int type, int tier, int gain, 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 *lruvec, int type) * 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 lruvec *lruvec, int swappiness) * 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); } -- 2.55.0