From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4465F2BDC0F for ; Sat, 29 Aug 2026 02:43:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787971439; cv=none; b=pAEQ3bEKltpatvkZ4ZsCCxPPkM2IfOW3D9sqxH/tPznTUQSh2fGYkDJ2ptJmJFLNloT+3nAmhICh1THKRtuQYYDu8MNpuWjfaKILYmdVUEm7r7UpGSqhP+W/rfxaAgpXrImJuVkXjx463NZsRyar8gWWH8zAcKwcXJyVpwWzkFM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787971439; c=relaxed/simple; bh=PArpqBearOf0tpsIBDw18Q2HELkhjLL1p0Hq/OaLRz0=; h=Date:To:From:Subject:Message-Id; b=D2xhOoAmOxhyHrdDZ68feVVk/pnafrNwSlVysbP4toTtTGaULlzIo96KxcpF1vjttUzTO7ZzxdI8pplYRjIsX1iioYILbPaKyjP1Kn1N1iknDdd6MlWFnP0DXbEnbwbMdQ/vw/UbwKyDac+ehhz4zhJoY2GH+UpuugIxojjo1IU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=tLQ2mes0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="tLQ2mes0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B22941F000E9; Sat, 29 Aug 2026 02:43:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1787971437; bh=Pl21a58rFiniOxRQsYa23jzHCpGRjTbuulEqaRsBXkQ=; h=Date:To:From:Subject; b=tLQ2mes0F5XW8Lf2zA29C9sCSAXGkIoxKkIGgZ5t8Iv1VAGy8mzpJY3TbWslnrSL+ v7OQ92b2t+/e66RRE7U4bBzL42guzDj19FdXATlspwMrvuyXNdA7BOnpDvQSG3KcZs cow+EqbaYPb0C+B83/eW6XMmNZKGx1PwyWPWVUJM= Date: Fri, 28 Aug 2026 19:43:57 -0700 To: mm-commits@vger.kernel.org,tjmercier@google.com,roman.gushchin@linux.dev,muchun.song@linux.dev,mhocko@suse.com,ljs@kernel.org,kasong@tencent.com,hannes@cmpxchg.org,david@kernel.org,baohua@kernel.org,axelrasmussen@google.com,shakeel.butt@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: + memcg-remove-lru_gen_soft_reclaim.patch added to mm-new branch Message-Id: <20260829024357.B22941F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: memcg: remove lru_gen_soft_reclaim() has been added to the -mm mm-new branch. Its filename is memcg-remove-lru_gen_soft_reclaim.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memcg-remove-lru_gen_soft_reclaim.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: Shakeel Butt Subject: memcg: remove lru_gen_soft_reclaim() Date: Tue, 11 Aug 2026 13:32:00 -0700 The soft limit rbtree was the only caller. Dropping it leaves MEMCG_LRU_HEAD unreachable, since nothing else ever rotates a memcg with that op, so remove the op too and update the memcg LRU comment. Link: https://lore.kernel.org/20260811203203.3456029-7-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Reviewed-by: T.J. Mercier Acked-by: Lorenzo Stoakes (ARM) Cc: Axel Rasmussen Cc: Barry Song Cc: David Hildenbrand Cc: Johannes Weiner Cc: Kairui Song Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 30 +++++++++++------------------- mm/vmscan.c | 16 ++-------------- 2 files changed, 13 insertions(+), 33 deletions(-) --- a/include/linux/mmzone.h~memcg-remove-lru_gen_soft_reclaim +++ a/include/linux/mmzone.h @@ -641,35 +641,32 @@ struct lru_gen_mm_walk { * For each node, memcgs are divided into two generations: the old and the * young. For each generation, memcgs are randomly sharded into multiple bins * to improve scalability. For each bin, the hlist_nulls is virtually divided - * into three segments: the head, the tail and the default. + * into two segments: the tail and the default. * * An onlining memcg is added to the tail of a random bin in the old generation. * The eviction starts at the head of a random bin in the old generation. The * per-node memcg generation counter, whose reminder (mod MEMCG_NR_GENS) indexes * the old generation, is incremented when all its bins become empty. * - * There are four operations: - * 1. MEMCG_LRU_HEAD, which moves a memcg to the head of a random bin in its - * current generation (old or young) and updates its "seg" to "head"; - * 2. MEMCG_LRU_TAIL, which moves a memcg to the tail of a random bin in its + * There are three operations: + * 1. MEMCG_LRU_TAIL, which moves a memcg to the tail of a random bin in its * current generation (old or young) and updates its "seg" to "tail"; - * 3. MEMCG_LRU_OLD, which moves a memcg to the head of a random bin in the old + * 2. MEMCG_LRU_OLD, which moves a memcg to the head of a random bin in the old * generation, updates its "gen" to "old" and resets its "seg" to "default"; - * 4. MEMCG_LRU_YOUNG, which moves a memcg to the tail of a random bin in the + * 3. MEMCG_LRU_YOUNG, which moves a memcg to the tail of a random bin in the * young generation, updates its "gen" to "young" and resets its "seg" to * "default". * * The events that trigger the above operations are: - * 1. Exceeding the soft limit, which triggers MEMCG_LRU_HEAD; - * 2. The first attempt to reclaim a memcg below low, which triggers + * 1. The first attempt to reclaim a memcg below low, which triggers * MEMCG_LRU_TAIL; - * 3. The first attempt to reclaim a memcg offlined or below reclaimable size + * 2. The first attempt to reclaim a memcg offlined or below reclaimable size * threshold, which triggers MEMCG_LRU_TAIL; - * 4. The second attempt to reclaim a memcg offlined or below reclaimable size + * 3. The second attempt to reclaim a memcg offlined or below reclaimable size * threshold, which triggers MEMCG_LRU_YOUNG; - * 5. Attempting to reclaim a memcg below min, which triggers MEMCG_LRU_YOUNG; - * 6. Finishing the aging on the eviction path, which triggers MEMCG_LRU_YOUNG; - * 7. Offlining a memcg, which triggers MEMCG_LRU_OLD. + * 4. Attempting to reclaim a memcg below min, which triggers MEMCG_LRU_YOUNG; + * 5. Finishing the aging on the eviction path, which triggers MEMCG_LRU_YOUNG; + * 6. Offlining a memcg, which triggers MEMCG_LRU_OLD. * * Notes: * 1. Memcg LRU only applies to global reclaim, and the round-robin incrementing @@ -702,7 +699,6 @@ void lru_gen_exit_memcg(struct mem_cgrou void lru_gen_online_memcg(struct mem_cgroup *memcg); void lru_gen_offline_memcg(struct mem_cgroup *memcg); void lru_gen_release_memcg(struct mem_cgroup *memcg); -void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid); void max_lru_gen_memcg(struct mem_cgroup *memcg, int nid); bool recheck_lru_gen_max_memcg(struct mem_cgroup *memcg, int nid); void lru_gen_reparent_memcg(struct mem_cgroup *memcg, struct mem_cgroup *parent, int nid); @@ -743,10 +739,6 @@ static inline void lru_gen_release_memcg { } -static inline void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid) -{ -} - static inline void max_lru_gen_memcg(struct mem_cgroup *memcg, int nid) { } --- a/mm/vmscan.c~memcg-remove-lru_gen_soft_reclaim +++ a/mm/vmscan.c @@ -4374,7 +4374,6 @@ bool lru_gen_look_around(struct page_vma /* see the comment on MEMCG_NR_GENS */ enum { MEMCG_LRU_NOP, - MEMCG_LRU_HEAD, MEMCG_LRU_TAIL, MEMCG_LRU_OLD, MEMCG_LRU_YOUNG, @@ -4396,9 +4395,7 @@ static void lru_gen_rotate_memcg(struct new = old = lruvec->lrugen.gen; /* see the comment on MEMCG_NR_GENS */ - if (op == MEMCG_LRU_HEAD) - seg = MEMCG_LRU_HEAD; - else if (op == MEMCG_LRU_TAIL) + if (op == MEMCG_LRU_TAIL) seg = MEMCG_LRU_TAIL; else if (op == MEMCG_LRU_OLD) new = get_memcg_gen(pgdat->memcg_lru.seq); @@ -4412,7 +4409,7 @@ static void lru_gen_rotate_memcg(struct hlist_nulls_del_rcu(&lruvec->lrugen.list); - if (op == MEMCG_LRU_HEAD || op == MEMCG_LRU_OLD) + if (op == MEMCG_LRU_OLD) hlist_nulls_add_head_rcu(&lruvec->lrugen.list, &pgdat->memcg_lru.fifo[new][bin]); else hlist_nulls_add_tail_rcu(&lruvec->lrugen.list, &pgdat->memcg_lru.fifo[new][bin]); @@ -4490,15 +4487,6 @@ unlock: } } -void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid) -{ - struct lruvec *lruvec = get_lruvec(memcg, nid); - - /* see the comment on MEMCG_NR_GENS */ - if (READ_ONCE(lruvec->lrugen.seg) != MEMCG_LRU_HEAD) - lru_gen_rotate_memcg(lruvec, MEMCG_LRU_HEAD); -} - bool recheck_lru_gen_max_memcg(struct mem_cgroup *memcg, int nid) { struct lruvec *lruvec = get_lruvec(memcg, nid); _ Patches currently in -mm which might be from shakeel.butt@linux.dev are memcg-clear-flushing_cached_charge-on-cpu-offline.patch memcg-trim-the-per-cpu-charge-stock-instead-of-draining-it.patch memcg-remove-v1-soft-limit-reclaim.patch memcg-remove-mem_cgroup_shrink_node.patch memcg-remove-the-soft-limit-reclaim-tracepoints.patch memcg-remove-the-soft-limit-rbtree.patch memcg-remove-lru_gen_soft_reclaim.patch memcg-remove-the-per-node-soft-limit-tree-fields.patch memcg-remove-mem_cgroup-soft_limit.patch memcg-simplify-v1-event-ratelimiting.patch