From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 932582ECD13; Fri, 20 Jun 2025 15:23:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750433039; cv=none; b=pdlmNGQfL7Atn0XrzS1RVPMfNBPpY3zgVcCTP+Ag1gC+OiGcoPoYWyXYmZxyq983XWpOO69ES0+JFQT9WheKolOUP4GSmHo7SuncJTuhXhQ8KthNut5y3cPNBXl6NlrD88dtjVtN6K/V/3D+1ubkMhXkQaUUTLScleU/Q0JE3lA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750433039; c=relaxed/simple; bh=puBcn1RLjuMlGziYQtO8T9w0Hol7ZIDbbn6QvjDV/zQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=duevx1ixkbQICAsEDxoRStdBy+2wHyaHjeWo7qm3t/KXWTVX6rP9SNL815DTyDozFwNg1HRYbSgrWVLHYY8kcAMIcqnyghy0cpdiVuIBetaAyEPVzl8vf4h5YET4YXNTPU6fsGjvC/fmlS5+30aQtjzHZ44DOo5jjxmF8v1LJqE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZuDPDV0N; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZuDPDV0N" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8EBFDC4CEE3; Fri, 20 Jun 2025 15:23:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750433039; bh=puBcn1RLjuMlGziYQtO8T9w0Hol7ZIDbbn6QvjDV/zQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZuDPDV0NqIta2HyKRSmvefpltNr5OQmlAiOy9JNjBp+KZ7zcKekZkV7tLDeT3G9FC B/xYcs9tQuK3L5hIeu3TK7veaQeloAMkKamwtfMv9j3wyItFJ4Jeyumk+lanosdVam h6v8DnSe9cqMa2epNROFZmS3FTYQlORrrO5dSX6Oe6zjXsdM5PHYt0SJEddqQSwRhM r8oWPFNNGOLwoy1BcwIn1UxB2q+NCo+QdxAzjbG01MEn7Q0JYWLL6RMd8XkyVh3qW2 MUtEaCFkMso3v8JTsxk5WyijDJMv3M/XMPmcVJo1eyD/+QqlZ8A2cFCJu/fzktD0hH lFIS1EL3Rqvvw== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Andrew Morton , Ingo Molnar , Johannes Weiner , Marco Crivellari , Michal Hocko , Michal Hocko , Muchun Song , Peter Zijlstra , Roman Gushchin , Shakeel Butt , Tejun Heo , Thomas Gleixner , Vlastimil Babka , Waiman Long , cgroups@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 16/27] sched/isolation: Flush memcg workqueues on cpuset isolated partition change Date: Fri, 20 Jun 2025 17:22:57 +0200 Message-ID: <20250620152308.27492-17-frederic@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250620152308.27492-1-frederic@kernel.org> References: <20250620152308.27492-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The HK_TYPE_DOMAIN housekeeping cpumask is now modifyable at runtime. In order to synchronize against memcg workqueue to make sure that no asynchronous draining is still pending or executing on a newly made isolated CPU, the housekeeping susbsystem must flush the memcg workqueues. However the memcg workqueues can't be flushed easily since they are queued to the main per-CPU workqueue pool. Solve this with creating a memcg specific pool and provide and use the appropriate flushing API. Signed-off-by: Frederic Weisbecker --- include/linux/memcontrol.h | 4 ++++ kernel/sched/isolation.c | 2 ++ kernel/sched/sched.h | 1 + mm/memcontrol.c | 12 +++++++++++- 4 files changed, 18 insertions(+), 1 deletion(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 87b6688f124a..ef5036c6bf04 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1046,6 +1046,8 @@ static inline u64 cgroup_id_from_mm(struct mm_struct *mm) return id; } +void mem_cgroup_flush_workqueue(void); + extern int mem_cgroup_init(void); #else /* CONFIG_MEMCG */ @@ -1451,6 +1453,8 @@ static inline u64 cgroup_id_from_mm(struct mm_struct *mm) return 0; } +static inline void mem_cgroup_flush_workqueue(void) { } + static inline int mem_cgroup_init(void) { return 0; } #endif /* CONFIG_MEMCG */ diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 7814d60be87e..6fb0c7956516 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -140,6 +140,8 @@ int housekeeping_update(struct cpumask *mask, enum hk_type type) synchronize_rcu(); + mem_cgroup_flush_workqueue(); + kfree(old); return 0; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 04094567cad4..53107c021fe9 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -44,6 +44,7 @@ #include #include #include +#include #include #include #include diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 29d44af6c426..928b90cdb5ba 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -96,6 +96,8 @@ static bool cgroup_memory_nokmem __ro_after_init; /* BPF memory accounting disabled? */ static bool cgroup_memory_nobpf __ro_after_init; +static struct workqueue_struct *memcg_wq __ro_after_init; + static struct kmem_cache *memcg_cachep; static struct kmem_cache *memcg_pn_cachep; @@ -1979,7 +1981,7 @@ static void schedule_drain_work(int cpu, struct work_struct *work) { housekeeping_lock(); if (!cpu_is_isolated(cpu)) - schedule_work_on(cpu, work); + queue_work_on(cpu, memcg_wq, work); housekeeping_unlock(); } @@ -5140,6 +5142,11 @@ void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) refill_stock(memcg, nr_pages); } +void mem_cgroup_flush_workqueue(void) +{ + flush_workqueue(memcg_wq); +} + static int __init cgroup_memory(char *s) { char *token; @@ -5182,6 +5189,9 @@ int __init mem_cgroup_init(void) cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL, memcg_hotplug_cpu_dead); + memcg_wq = alloc_workqueue("memcg", 0, 0); + WARN_ON(!memcg_wq); + for_each_possible_cpu(cpu) { INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work, drain_local_memcg_stock); -- 2.48.1