From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f42.google.com (mail-ot1-f42.google.com [209.85.210.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 571EE444704 for ; Fri, 7 Aug 2026 20:21:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786134071; cv=none; b=iYr71rgGkk32ZYnnQ5Gn4kPaxQqFYDvXueDo8hVT8rNhg21XENAcRvQDWZblXXpaFNqYqBsNesQddlooiHkYvSSRmM0chL18mIcYA72GiIuGX5tOUeG/tyEUwVyPwXe5zhcMGAcD5HRzD1b4e0xfWlpuHGPcjH7rX5DZoZMwQsk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786134071; c=relaxed/simple; bh=cvy8xs5odfKdlZvQWmVQYRS0OJ7R2YTEIC6VhLVlmYM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gxw7NVAja0DpFDiXSCVWMeM/BJswlgs4VrwHHoscpViCM9d84OKeHMPcSmqE8Lv+49bYRS74eFfq8TK8nGo0eDLNDp6wahJhzAVyEYCNdK2MLZcjY2wAWmXzHtu3m85R4dyuJNILmTSXEN4UT5FKeb0Bv6li3pk3uajguHq9IpE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=m/2p5+DC; arc=none smtp.client-ip=209.85.210.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="m/2p5+DC" Received: by mail-ot1-f42.google.com with SMTP id 46e09a7af769-7eb545db3afso5768a34.0 for ; Fri, 07 Aug 2026 13:21:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786134069; x=1786738869; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=5vEVg85rEvrzvIwoN3Uc+WskLG7iLQIioETffuSYNDk=; b=m/2p5+DCfwh579mm/HZea72TYbGe8crCuFyyofCi0a3O8phGn1dASa0vl4MbFUDaVc 6RQdJKkPxcgB5yfLJLJ6a4opsxS1I8EtaeNslV6UhTBFPwVKII+WVxkStDfGNCt9uHXG 5ugJp+ORVYI8I8kqYQ/zKw17tuWDZE2sAIcnWMgujVfoj0Gon7z0JxfErBJHHz1GlhE5 dPNHRpseCBQktp0JMI1sJt7VOo5zaeRAjp9qNCxga4XcPZsJE1DfdtQ+32Sb7ipdopYv VocqQNa3aptoknWpVUw6lBILejtklpuIjrmEgFRibQTrEQEAcdsjQZuluLb4gipw+DVj uhbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786134069; x=1786738869; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=5vEVg85rEvrzvIwoN3Uc+WskLG7iLQIioETffuSYNDk=; b=chcVt+vCjfb6hV8FvZhVGRsQP4d3/3AVg71anwBAlRWu1l1z8kN+XKYblKQRcuBcYU pGC2K2pNwUVTEIjDyWHjnhk+cJm7LSOheosEY0vB2T2aNQlhNl2tLFuVZdksTx2R72AN NQVX6EOfqCJnEXahD21T3Z3ZoTKCWnaZkDg2D0Nse8VDW3+jA9JlGVRSGEuUyZ+ZaGGm ebyaidZy0h3zhriJKF359y2LCc+EkFciRlh/jAydbalvplJRnWkJfVHZ8M3eCaol6lxw sPUUHiB7Dyxidx7MqLqdUjlng7Of623sr2bXZEQbwhJq91azF5VUrDlntyeShA7tzb9u gWXw== X-Forwarded-Encrypted: i=1; AHgh+RrabHfaLXSzotBCSZc9c2kKhVMhgL1rJMipNXBczaMvVbYasdqb4tIcXlnDxRL+AymsDv0LJlsXRVPF7IY=@vger.kernel.org X-Gm-Message-State: AOJu0Yy/jgTrjUhZiGEnZr4k3pGAR1dDrZ3KtfGEu3yTCBOYBNYfUPID 9wDvN71c2+ONw509dGc2J0eSUmhjomGDTOv9qjUy3hyGN+ahIMR2b/Cm X-Gm-Gg: AR+sD10vr1PnyEbF3eNNZMp32NoWMb3xD1UJN04BJ4GNjdfN71qPHi6zDAs0JHCf0q0 T+VG9gC1auf/ONbCwgkpTTXds/caE6nUzgnixoSq4nq/sBPVxce9tRxVJO9URInzfCwlHwFd02K oXlnoGiW1R05jQtMYR16NWlHzN9qx4IM4gDBWm7kiagsAwoyEalUsOJtiFd6l/KwZ0Er0ilYH0o yXXh+Xf62o+r5sL9ZX+5zVgYF+y+Ns3lPg9ebI0fym+lcCw3pwMuP13U5cXll4py3DLZDpx3HMs HFiWTRkjfrfaZFki+HhIFvVvoQKYRofEpAWwiJ2mZCh4rI6FMjeczQQo9Wm0IbtVo13x70S70cf Qp/kBgnMmAPfRjTM7lsLfmjJaIYF0gzbt+Wahxbda1baTnM4HM0etmLW10PWYuzSMhurznm42ML kYeC3V8nhq86V7u7eYFW++n83wHxrUXnzzLtxvnPkM+CtyquICirAARrGXgxUjmSK4ye2bH3ooa ppgU1sOvoKDbWqPXA== X-Received: by 2002:a05:6820:168f:b0:6ae:9b39:68d1 with SMTP id 006d021491bc7-6b0420d5753mr1429497eaf.23.1786134068227; Fri, 07 Aug 2026 13:21:08 -0700 (PDT) Received: from localhost ([2a03:2880:10ff:4::]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-6b02be475f7sm2836904eaf.9.2026.08.07.13.21.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Aug 2026 13:21:07 -0700 (PDT) From: Joshua Hahn To: Johannes Weiner , Gregory Price Cc: Alistair Popple , Andrew Morton , Axel Rasmussen , Barry Song , Ben Segall , Brendan Jackman , Byungchul Park , David Hildenbrand , David Rientjes , Dietmar Eggemann , "Harry Yoo (Oracle)" , Ingo Molnar , Juri Lelli , K Prateek Nayak , Kairui Song , "Liam R. Howlett" , Lorenzo Stoakes , Matthew Brost , Mel Gorman , Michal Hocko , Michal Hocko , Mike Rapoport , Muchun Song , Peter Zijlstra , Qi Zheng , Rakie Kim , Roman Gushchin , Shakeel Butt , Steven Rostedt , Suren Baghdasaryan , "T.J. Mercier" , Valentin Schneider , Vincent Guittot , Vlastimil Babka , Wei Xu , Ying Huang , Yosry Ahmed , Yuanchu Xie , Zi Yan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@meta.com Subject: [RFC PATCH v3 05/14] mm/memcontrol: Set tier limits proportional to memory limits Date: Fri, 7 Aug 2026 13:20:48 -0700 Message-ID: <20260807202059.2620949-6-joshua.hahnjy@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260807202059.2620949-1-joshua.hahnjy@gmail.com> References: <20260807202059.2620949-1-joshua.hahnjy@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Compute proportional per-tier limits based on memory limits when users write to memory limit sysfs files, or when memory hotplug causes tier proportions to be shifted. No-op unless the system has tiered memcg limits enabled. Signed-off-by: Joshua Hahn --- include/linux/memcontrol.h | 10 +++++++ include/linux/memory-tiers.h | 6 ++++ mm/memcontrol.c | 54 ++++++++++++++++++++++++++++++++++++ mm/memory-tiers.c | 13 +++++++++ 4 files changed, 83 insertions(+) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index bb5bde87ac85a..f7a92b66330ec 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -537,11 +537,17 @@ static inline bool mem_cgroup_tiered_limits(void) { return static_branch_unlikely(&memcg_tiered_limits_key); } + +void establish_memcg_tier_limits(void); #else static inline bool mem_cgroup_tiered_limits(void) { return false; } + +static inline void establish_memcg_tier_limits(void) +{ +} #endif static inline void mem_cgroup_protection(struct mem_cgroup *root, @@ -1102,6 +1108,10 @@ static inline bool mem_cgroup_tiered_limits(void) return false; } +static inline void establish_memcg_tier_limits(void) +{ +} + static inline void memcg_memory_event(struct mem_cgroup *memcg, enum memcg_memory_event event) { diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 0e49645cdd1a9..04b396f60b457 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -55,6 +55,7 @@ struct memory_dev_type *mt_find_alloc_memory_type(int adist, struct list_head *memory_types); void mt_put_memory_types(struct list_head *memory_types); const nodemask_t *mt_tier_nodes(int slot); +unsigned long mt_scale_by_tier(unsigned long val, int slot); #ifdef CONFIG_NUMA_MIGRATION int next_demotion_node(int node, const nodemask_t *allowed_mask); void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets); @@ -169,5 +170,10 @@ static inline const nodemask_t *mt_tier_nodes(int slot) { return NULL; } + +static inline unsigned long mt_scale_by_tier(unsigned long val, int slot) +{ + return val; +} #endif /* CONFIG_NUMA */ #endif /* _LINUX_MEMORY_TIERS_H */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d096010366515..defd04acfb3fd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4421,6 +4421,35 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css) mem_cgroup_free(memcg); } +static inline unsigned long page_counter_max_or_scale(unsigned long val, + int slot) +{ + return val == PAGE_COUNTER_MAX ? PAGE_COUNTER_MAX : + mt_scale_by_tier(val, slot); +} + +static void memcg_scale_tier_limits(struct mem_cgroup *memcg) +{ + unsigned long min = READ_ONCE(memcg->memory.min); + unsigned long low = READ_ONCE(memcg->memory.low); + unsigned long high = READ_ONCE(memcg->memory.high); + unsigned long max = READ_ONCE(memcg->memory.max); + int nr_tier_slots = mt_nr_tier_slots(); + + for (int slot = 0; slot < nr_tier_slots; slot++) { + unsigned long new_min = page_counter_max_or_scale(min, slot); + unsigned long new_low = page_counter_max_or_scale(low, slot); + unsigned long new_high = page_counter_max_or_scale(high, slot); + unsigned long new_max = page_counter_max_or_scale(max, slot); + struct page_counter *tier = &memcg->tier[slot]; + + page_counter_set_min(tier, new_min); + page_counter_set_low(tier, new_low); + page_counter_set_high(tier, new_high); + xchg(&tier->max, new_max); + } +} + /** * mem_cgroup_css_reset - reset the states of a mem_cgroup * @css: the target css @@ -4454,6 +4483,8 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css) page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX); memcg1_soft_limit_reset(memcg); page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX); + if (mem_cgroup_tiered_limits()) + memcg_scale_tier_limits(memcg); memcg_wb_domain_size_changed(memcg); } @@ -4797,6 +4828,21 @@ static ssize_t memory_peak_write(struct kernfs_open_file *of, char *buf, &memcg->memory_peaks); } +#ifdef CONFIG_NUMA +void establish_memcg_tier_limits(void) +{ + struct mem_cgroup *memcg; + + if (!mem_cgroup_tiered_limits()) + return; + + for_each_mem_cgroup_tree(memcg, NULL) { + if (memcg != root_mem_cgroup) + memcg_scale_tier_limits(memcg); + } +} +#endif + #undef OFP_PEAK_UNSET static int memory_min_show(struct seq_file *m, void *v) @@ -4818,6 +4864,8 @@ static ssize_t memory_min_write(struct kernfs_open_file *of, return err; page_counter_set_min(&memcg->memory, min); + if (mem_cgroup_tiered_limits()) + memcg_scale_tier_limits(memcg); return nbytes; } @@ -4841,6 +4889,8 @@ static ssize_t memory_low_write(struct kernfs_open_file *of, return err; page_counter_set_low(&memcg->memory, low); + if (mem_cgroup_tiered_limits()) + memcg_scale_tier_limits(memcg); return nbytes; } @@ -4866,6 +4916,8 @@ static ssize_t memory_high_write(struct kernfs_open_file *of, return err; page_counter_set_high(&memcg->memory, high); + if (mem_cgroup_tiered_limits()) + memcg_scale_tier_limits(memcg); if (of->file->f_flags & O_NONBLOCK) goto out; @@ -4925,6 +4977,8 @@ static ssize_t memory_max_write(struct kernfs_open_file *of, return err; xchg(&memcg->memory.max, max); + if (mem_cgroup_tiered_limits()) + memcg_scale_tier_limits(memcg); if (of->file->f_flags & O_NONBLOCK) goto out; diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index bd5c78cd26ec4..e2c99f51c36d1 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -810,6 +810,7 @@ static int __init memory_tier_late_init(void) establish_demotion_targets(); establish_tier_slots(); + establish_memcg_tier_limits(); put_online_mems(); return 0; @@ -967,6 +968,16 @@ const nodemask_t *mt_tier_nodes(int slot) return &tier_nodemasks[slot]; } +unsigned long mt_scale_by_tier(unsigned long val, int slot) +{ + unsigned long total_capacity = totalram_pages(); + + if (slot < 0 || !total_capacity) + return 0; + + return mult_frac(val, READ_ONCE(tier_capacity[slot]), total_capacity); +} + static int __meminit memtier_hotplug_callback(struct notifier_block *self, unsigned long action, void *_arg) { @@ -979,6 +990,7 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self, if (clear_node_memory_tier(nn->nid)) { establish_demotion_targets(); establish_tier_slots(); + establish_memcg_tier_limits(); } mutex_unlock(&memory_tier_lock); break; @@ -988,6 +1000,7 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self, if (!IS_ERR(memtier)) { establish_demotion_targets(); establish_tier_slots(); + establish_memcg_tier_limits(); } mutex_unlock(&memory_tier_lock); break; -- 2.53.0-Meta