From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794694259; b=eeWWSA0oXjmzJBg0OFZH1lqxhNsgNtL3yWb3nOlrIo72JcHCPNrwQVWRdjPo4Fzm21dA vSfaPov11VIovkXVaDdU9ADX+BSQ+6WAbt4WFI3YvbhsT0EAUvhA628XhwMyb3Ix2PFRJ zffJmROttWZFmtKB/sNaV65VXYcSM/v/JMEFa5VSuXWjnErRTGCYvfJ0myFf3Jinm9HRt GoRr76zk6O8W26G1R8TwFSTBwVgn/uoXc9GyE1YgGYWQAXrm6Ovr7TrFG5UAZap7R/bJB XhNO3MK26NiUqJSv0ehjaRkhRtdX25F5ddlCgDBbEvtEI2cyoECfn7adCMwUC3RY8hA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794694259; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=USJchwg/G8VhxpafafCNLghAGz3skECn7beQNjVA7l4=; b=SJrwPcwCh0hYwGyI/5WOCsDTi7Gum5iERxEIGYB+ZzHs03WWaNArjhj7fsC0di7V+1ud suQ0iVckkEjYRAOygN3R1rwHkzD8aCP4lD7FPTbiAMPN4CIH3EI9e0C+9Pqq4gx3ds+mw QasqhlyF8OzvuPwVMBDCrnwjWpfOCCgeLvp8JOqaAoCnXGeGWH+w88e0xS/LgpfkdSpXi ThEoocNvofEAPMK5xiJev2PRf9EC8M52pXKPFAuBOOucwW48Zudq4a5ZcHN63LJfMzSTJ 5eKpECUfAB0BKEQkMJaBp+64VfphKvuerMAxrHLJdDXdT6iUwNHHgyES7DuSJqyv5Sg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=vGQv5+H9; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 780EA606A329 for ; Sat, 14 Nov 2026 22:10:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=vGQv5+H9 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41AE21F000C4; Sat, 14 Nov 2026 22:10:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1794694259; bh=USJchwg/G8VhxpafafCNLghAGz3skECn7beQNjVA7l4=; h=Date:To:From:Subject; b=vGQv5+H9HuAss/JPOBsQXNqzvGH8O6b9xKnjbrlYPhgN3WUs/eCBDucZWlfkbCdTM qM2ogu1KT83CHclcWbdX5rTRhAugAQodLaKTtMlJPdaC6imwn+R8njYb9D80tRie4J KRIcePVGajnSI9jBQfPGu8ahNvaHpVm99iJPGX/4= Date: Sat, 14 Nov 2026 14:10:58 -0800 To: mm-commits@vger.kernel.org,baohua@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-mglru-restrict-eviction-accounting-to-eligible-zones.patch added to mm-new branch Message-Id: <20261114221059.41AE21F000C4@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The patch titled Subject: mm/mglru: Restrict eviction accounting to eligible zones has been added to the -mm mm-new branch. Its filename is mm-mglru-restrict-eviction-accounting-to-eligible-zones.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-restrict-eviction-accounting-to-eligible-zones.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: "Barry Song (Xiaomi)" Subject: mm/mglru: Restrict eviction accounting to eligible zones Date: Sun, 15 Nov 2026 04:07:59 +0800 For both lruvec_evictable_size() and lru_gen_imbalanced(), only count eligible zones up to sc->reclaim_idx. This avoids overestimating the number of pages available for scanning and allows aging to proceed more promptly when eligible zones contain few folios. lru_gen_age_node() uses lruvec_is_reclaimable() to determine whether any memcg has generations old enough to reclaim under min_ttl. If none are reclaimable, it may trigger OOM. However, lruvec_is_reclaimable() also uses lruvec_is_sizable() to estimate the LRU size. Previously, lruvec_is_sizable() counted folios across all zones. With accounting now restricted to zones up to sc->reclaim_idx, the estimated size may be significantly smaller, potentially leading to premature OOM. To avoid this and simplify the implementation, allow lru_gen_age_node() to count folios from all zones. Note that min_ttl currently has several issues and does not work as expected. First, reclaim does not enforce min_ttl on a per-memcg basis, so folios from memcgs whose generations are all younger than min_ttl can still be reclaimed. Second, the LRU size check is coupled with the min_ttl check, which can lead to premature OOM. For example, consider a system with 100 memcgs, each containing fewer than 16 MB of evictable folios. At priority 12, shifting each memcg's LRU size by sc->priority can yield zero, causing all memcgs to be considered unreclaimable even if their generations are older than min_ttl. These issues should be addressed in a separate patch series rather than as part of this eviction accounting change. Link: https://lore.kernel.org/20261114200803.23129-13-baohua@kernel.org Signed-off-by: Bo Zhang Signed-off-by: Barry Song (Xiaomi) Signed-off-by: Andrew Morton Co-developed-by: Bo Zhang Cc: Axel Rasmussen Cc: Baolin Wang Cc: Baoquan He Cc: Johannes Weiner Cc: Cc: Kairui Song Cc: Kunwu Chan Cc: Liam R. Howlett Cc: wang lian Cc: Cc: Cc: Michal Hocko Cc: Qi Zheng Cc: Ridong Chen Cc: Mike Rapoport Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: wangzicheng Cc: Wei Xu Cc: Yuanchu Xie Cc: Hui Zhu Cc: Siddharth Chintamaneni Cc: Bo Zhang mm/trace_vmscan.h | 4 ++-- mm/vmscan.c | 27 +++++++++++++++------------ mm/vmscan.h | 7 ++++--- 3 files changed, 21 insertions(+), 17 deletions(-) --- a/mm/trace_vmscan.h~mm-mglru-restrict-eviction-accounting-to-eligible-zones +++ a/mm/trace_vmscan.h @@ -488,9 +488,9 @@ TRACE_EVENT(mm_mglru_aging, unsigned long seq = max_seq - MAX_NR_GENS + 1 + i; __entry->nr_anon[i] = - lruvec_gen_size(lrugen, LRU_GEN_ANON, seq); + lruvec_gen_size(lrugen, LRU_GEN_ANON, seq, MAX_NR_ZONES); __entry->nr_file[i] = - lruvec_gen_size(lrugen, LRU_GEN_FILE, seq); + lruvec_gen_size(lrugen, LRU_GEN_FILE, seq, MAX_NR_ZONES); } __entry->nid = lruvec_pgdat(lruvec)->node_id; __entry->priority = sc->priority; --- a/mm/vmscan.c~mm-mglru-restrict-eviction-accounting-to-eligible-zones +++ a/mm/vmscan.c @@ -4207,8 +4207,9 @@ static void set_initial_priority(struct sc->priority = clamp(priority, DEF_PRIORITY / 2, DEF_PRIORITY); } -static void lruvec_evictable_size(struct lruvec *lruvec, int swappiness, - unsigned long nr[]) +static void lruvec_evictable_size(struct lruvec *lruvec, struct scan_control *sc, + int swappiness, unsigned long nr[], + int max_zone) { int type; unsigned long seq; @@ -4221,16 +4222,17 @@ static void lruvec_evictable_size(struct for_each_evictable_type(type, swappiness) { for (seq = min_seq[type]; seq <= max_seq; seq++) - nr[type] += lruvec_gen_size(lrugen, type, seq); + nr[type] += lruvec_gen_size(lrugen, type, seq, max_zone); } } -static bool lruvec_is_sizable(struct lruvec *lruvec, struct scan_control *sc) +static bool lruvec_is_sizable(struct lruvec *lruvec, struct scan_control *sc, + int max_zone) { unsigned long total, sizes[ANON_AND_FILE]; int swappiness = get_swappiness(lruvec, sc); - lruvec_evictable_size(lruvec, swappiness, sizes); + lruvec_evictable_size(lruvec, sc, swappiness, sizes, max_zone); total = sizes[LRU_GEN_ANON] + sizes[LRU_GEN_FILE]; /* whether the size is big enough to be helpful */ @@ -4249,7 +4251,8 @@ static bool lruvec_is_reclaimable(struct if (mem_cgroup_below_min(NULL, memcg)) return false; - if (!lruvec_is_sizable(lruvec, sc)) + /* counting all zones to avoid premature OOM */ + if (!lruvec_is_sizable(lruvec, sc, MAX_NR_ZONES)) return false; gen = lru_gen_from_seq(evictable_min_seq(min_seq, swappiness)); @@ -5102,9 +5105,9 @@ static bool lru_gen_imbalanced(struct lr for_each_evictable_type(type, swappiness) { unsigned long seq; - youngest[type] = lruvec_gen_size(lrugen, type, max_seq); + youngest[type] = lruvec_gen_size(lrugen, type, max_seq, sc->reclaim_idx + 1); for (seq = min_seq[type]; seq < max_seq; seq++) - old[type] += lruvec_gen_size(lrugen, type, seq); + old[type] += lruvec_gen_size(lrugen, type, seq, sc->reclaim_idx + 1); } /* the vast majority of pages sit in the youngest gen */ @@ -5139,7 +5142,7 @@ static void lru_gen_prepare_scan(struct { unsigned long total; - lruvec_evictable_size(lruvec, swappiness, nr_to_scan); + lruvec_evictable_size(lruvec, sc, swappiness, nr_to_scan, sc->reclaim_idx + 1); total = nr_to_scan[LRU_GEN_ANON] + nr_to_scan[LRU_GEN_FILE]; total = apply_proportional_protection(memcg, sc, total); @@ -5326,7 +5329,7 @@ static int shrink_one(struct lruvec *lru if (need_rotate) return MEMCG_LRU_YOUNG; - if (lruvec_is_sizable(lruvec, sc)) + if (lruvec_is_sizable(lruvec, sc, sc->reclaim_idx + 1)) return 0; /* one retry if too small */ @@ -5856,7 +5859,7 @@ static int lru_gen_seq_show(struct seq_f char mark = full && seq < min_seq[type] ? 'x' : ' '; seq_printf(m, " %10lu%c", - lruvec_gen_size(lrugen, type, seq), mark); + lruvec_gen_size(lrugen, type, seq, MAX_NR_ZONES), mark); } seq_putc(m, '\n'); @@ -5909,7 +5912,7 @@ static int run_eviction(struct lruvec *l if (sc->nr_reclaimed >= nr_to_reclaim) return 0; - lruvec_evictable_size(lruvec, swappiness, nr_to_scan); + lruvec_evictable_size(lruvec, sc, swappiness, nr_to_scan, sc->reclaim_idx + 1); lru_gen_balance_scan(lruvec, swappiness, nr_to_reclaim - sc->nr_reclaimed, nr_to_scan); --- a/mm/vmscan.h~mm-mglru-restrict-eviction-accounting-to-eligible-zones +++ a/mm/vmscan.h @@ -117,14 +117,15 @@ struct scan_control { }; #ifdef CONFIG_LRU_GEN -/* The number of pages of @type in the generation @seq, summed over all zones */ +/* Number of pages of @type in generation @seq below @max_zone */ static inline unsigned long lruvec_gen_size(struct lru_gen_folio *lrugen, - int type, unsigned long seq) + int type, unsigned long seq, + int max_zone) { int gen = lru_gen_from_seq(seq); unsigned long size = 0; - for (int zone = 0; zone < MAX_NR_ZONES; zone++) + for (int zone = 0; zone < max_zone; zone++) size += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L); return size; _ Patches currently in -mm which might be from baohua@kernel.org are arm64-vmalloc-allow-arch_vmap_pte_range_map_size-to-batch-multiple-cont_pte.patch mm-vmalloc-extend-page-table-walk-to-support-larger-page_shift-sizes-and-eliminate-page-table-rewalk.patch mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible.patch mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.patch mm-mglru-avoid-placing-rejected-folios-below-populated-gen.patch mm-mglru-run-aging-when-one-type-is-drained.patch mm-mglru-run-aging-when-one-type-is-drained-fix.patch mm-mglru-restrict-eviction-accounting-to-eligible-zones.patch mm-mglru-reduce-lru-lock-contention-by-shrinking-folio-batches-in-inc_min_seq.patch mm-mglru-make-swappiness=1-file-reclaim-more-aggressive.patch