From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B5D0C3ABD8 for ; Fri, 16 May 2025 06:50:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E5CBA6B00C5; Fri, 16 May 2025 02:50:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E0AAF6B00C6; Fri, 16 May 2025 02:50:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CAADF6B00C7; Fri, 16 May 2025 02:50:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A8CCC6B00C5 for ; Fri, 16 May 2025 02:50:15 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 035281A1783 for ; Fri, 16 May 2025 06:50:16 +0000 (UTC) X-FDA: 83447846874.13.8084A2F Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) by imf30.hostedemail.com (Postfix) with ESMTP id 4F09180005 for ; Fri, 16 May 2025 06:50:15 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=siOP1XI+; spf=pass (imf30.hostedemail.com: domain of shakeel.butt@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747378215; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rMkhHE3/mY4LwdWFLkKMdTI5kaoAKFQu40eQRc8Gq7c=; b=jEkgU+WhvHRcG2isTpsUodUK4HP6WSk+Kb26R0L4j9jv621cGR5XncQO7ERIRXiH2/02kt urq+QJQVA4K4wQMCDUVp8Nf99Ph4VenHr++1Oaqp9mpYi0DZUUX/hnUp+UdzcZZE5tCJRb rMCCkeiDjAWwAkhoO0N1T6hmtkQsr4I= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=siOP1XI+; spf=pass (imf30.hostedemail.com: domain of shakeel.butt@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1747378215; a=rsa-sha256; cv=none; b=h183HA8lA2bOTyD/NIoIBI1LawlKNADuk5HSQqRoWe9zlnr+0dn+HYkE8n9/MYYS+TtzCH ATeCwihLf+bNXLuKUqjvTrcoSCmb802eeLBmAno6yPpcxiCh8Y1SXBDuPJp11bnuNOP0iV tR4IkvtS4ZcLpcc4ClYpfDP0959zAZY= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1747378214; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rMkhHE3/mY4LwdWFLkKMdTI5kaoAKFQu40eQRc8Gq7c=; b=siOP1XI+4UsJf4QcPdJTLENFgNL3vd8HYedjMVroCwakJlLDn86JD4Qc4+nqwIm8+F87sI kqlqdNKpEZ4nDYd76Re7gsHiCM1qQT38MtpIP7DJ7FJAY/lWAM3GbK7iGbZo2mD3WJdZyJ 4jB0niGQ+ZYUpCNX1Oa1k50J3tj2xwE= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Vlastimil Babka , Alexei Starovoitov , Sebastian Andrzej Siewior , Harry Yoo , Yosry Ahmed , Peter Zijlstra , Mathieu Desnoyers , bpf@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [PATCH 5/5] memcg: make memcg_rstat_updated nmi safe Date: Thu, 15 May 2025 23:49:12 -0700 Message-ID: <20250516064912.1515065-6-shakeel.butt@linux.dev> In-Reply-To: <20250516064912.1515065-1-shakeel.butt@linux.dev> References: <20250516064912.1515065-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: 4F09180005 X-Rspamd-Server: rspam09 X-Stat-Signature: yfrfjauqszcys3ibumnrwuipawdaoma4 X-HE-Tag: 1747378215-37631 X-HE-Meta: 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 CNas6U9Z iM9qfrGI4/fFqUOmnPzJe5UviLC5fLPtfiUpfaeYHuhAWCw/Jll5CnyLstaz8QsPnNROVI9GmTpztxh2rh2vALuy6xvzZNb5F9qNMvYitjs+rkoy9GGrCmwGwARlazGNdwFTv+28xDTmSpq0+Zaw7dHPNlKjGuQEhbbEVecQvSAmSzsLn+Bol6kWqHiQ8CMrl/XCzXUCZ+IZ1SfVnWtxQnHaleshTb7iND2fV X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: memcg: convert stats_updates to atomic_t Currently kernel maintains memory related stats updates per-cgroup to optimize stats flushing. The stats_updates is defined as atomic64_t which is not nmi-safe on some archs. Actually we don't really need 64bit atomic as the max value stats_updates can get should be less than nr_cpus * MEMCG_CHARGE_BATCH. A normal atomic_t should suffice. Also the function cgroup_rstat_updated() is still not nmi-safe but there is parallel effort to make it nmi-safe, so until then let's ignore it in the nmi context. Signed-off-by: Shakeel Butt --- mm/memcontrol.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 85519ce37f18..06d5d5407b00 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -533,7 +533,7 @@ struct memcg_vmstats { unsigned long events_pending[NR_MEMCG_EVENTS]; /* Stats updates since the last flush */ - atomic64_t stats_updates; + atomic_t stats_updates; }; /* @@ -559,7 +559,7 @@ static u64 flush_last_time; static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats) { - return atomic64_read(&vmstats->stats_updates) > + return atomic_read(&vmstats->stats_updates) > MEMCG_CHARGE_BATCH * num_online_cpus(); } @@ -573,7 +573,9 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val, if (!val) return; - cgroup_rstat_updated(memcg->css.cgroup, cpu); + /* TODO: add to cgroup update tree once it is nmi-safe. */ + if (!in_nmi()) + cgroup_rstat_updated(memcg->css.cgroup, cpu); statc_pcpu = memcg->vmstats_percpu; for (; statc_pcpu; statc_pcpu = statc->parent_pcpu) { statc = this_cpu_ptr(statc_pcpu); @@ -591,7 +593,7 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val, continue; stats_updates = this_cpu_xchg(statc_pcpu->stats_updates, 0); - atomic64_add(stats_updates, &statc->vmstats->stats_updates); + atomic_add(stats_updates, &statc->vmstats->stats_updates); } } @@ -599,7 +601,7 @@ static void __mem_cgroup_flush_stats(struct mem_cgroup *memcg, bool force) { bool needs_flush = memcg_vmstats_needs_flush(memcg->vmstats); - trace_memcg_flush_stats(memcg, atomic64_read(&memcg->vmstats->stats_updates), + trace_memcg_flush_stats(memcg, atomic_read(&memcg->vmstats->stats_updates), force, needs_flush); if (!force && !needs_flush) @@ -4132,8 +4134,8 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) } WRITE_ONCE(statc->stats_updates, 0); /* We are in a per-cpu loop here, only do the atomic write once */ - if (atomic64_read(&memcg->vmstats->stats_updates)) - atomic64_set(&memcg->vmstats->stats_updates, 0); + if (atomic_read(&memcg->vmstats->stats_updates)) + atomic_set(&memcg->vmstats->stats_updates, 0); } static void mem_cgroup_fork(struct task_struct *task) -- 2.47.1