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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15CFFC433EF for ; Tue, 23 Nov 2021 11:02:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235892AbhKWLFT (ORCPT ); Tue, 23 Nov 2021 06:05:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235714AbhKWLFH (ORCPT ); Tue, 23 Nov 2021 06:05:07 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8981FC061574; Tue, 23 Nov 2021 03:01:59 -0800 (PST) Date: Tue, 23 Nov 2021 11:01:56 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1637665317; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LIhB7UzBQSvIeozWT8Qm1mGnc0Yz0NsQ0uRmpjIIse0=; b=B7sRPFYWOEP5s78lKjW1LduwKMflNH9Y5I4zzqhGT3egoBpwT77W7AenuFYO05ZeUmMFW+ +7af/w65ZiDWdIzpJh8DVhvezF2WxQvBoTno1H8YmpTHvYZbZzZ296AZsF6pUJSuXpBUls /2bxbFi8o/TfzN1y6qrdq12kEWbhgxuL9x1m02BF3XB44lIa2i+pZSHkyPn1RuLqtWRSSK iWFBQNByct+HJvP2XNt3VzmJAcHjJ8wdmwnB2ZB7T4kDsLzJd/ipKjM8DGhje8Ld9A55K+ 7bzhUw3nJ/84ApIcK3ZXeK7RPkZySYgSrcI8rOVEzvmyOz0A5zZNMg9vlT8HjA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1637665317; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LIhB7UzBQSvIeozWT8Qm1mGnc0Yz0NsQ0uRmpjIIse0=; b=9fXB7juZM3/RH7XGXv0hvZmvYy3V6QrAUja9/Q4uvEdEZYdrutioLbX+iyQ1WFZrU9vo3G vv+pXkNpzPILqOAA== From: "tip-bot2 for Andrey Ryabinin" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/cpuacct: Fix user/system in shown cpuacct.usage* Cc: Andrey Ryabinin , "Peter Zijlstra (Intel)" , Daniel Jordan , Tejun Heo , , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20211115164607.23784-3-arbn@yandex-team.com> References: <20211115164607.23784-3-arbn@yandex-team.com> MIME-Version: 1.0 Message-ID: <163766531610.11128.4606533243809880416.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: dd02d4234c9a2214a81c57a16484304a1a51872a Gitweb: https://git.kernel.org/tip/dd02d4234c9a2214a81c57a16484304a1a51872a Author: Andrey Ryabinin AuthorDate: Mon, 15 Nov 2021 19:46:06 +03:00 Committer: Peter Zijlstra CommitterDate: Tue, 23 Nov 2021 09:55:22 +01:00 sched/cpuacct: Fix user/system in shown cpuacct.usage* cpuacct has 2 different ways of accounting and showing user and system times. The first one uses cpuacct_account_field() to account times and cpuacct.stat file to expose them. And this one seems to work ok. The second one is uses cpuacct_charge() function for accounting and set of cpuacct.usage* files to show times. Despite some attempts to fix it in the past it still doesn't work. Sometimes while running KVM guest the cpuacct_charge() accounts most of the guest time as system time. This doesn't match with user&system times shown in cpuacct.stat or proc//stat. Demonstration: # git clone https://github.com/aryabinin/kvmsample # make # mkdir /sys/fs/cgroup/cpuacct/test # echo $$ > /sys/fs/cgroup/cpuacct/test/tasks # ./kvmsample & # for i in {1..5}; do cat /sys/fs/cgroup/cpuacct/test/cpuacct.usage_sys; sleep 1; done 1976535645 2979839428 3979832704 4983603153 5983604157 Use cpustats accounted in cpuacct_account_field() as the source of user/sys times for cpuacct.usage* files. Make cpuacct_charge() to account only summary execution time. Fixes: d740037fac70 ("sched/cpuacct: Split usage accounting into user_usage and sys_usage") Signed-off-by: Andrey Ryabinin Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Jordan Acked-by: Tejun Heo Cc: Link: https://lore.kernel.org/r/20211115164607.23784-3-arbn@yandex-team.com --- kernel/sched/cpuacct.c | 79 ++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 47 deletions(-) diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index f347cf9..9de7dd5 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -21,15 +21,11 @@ static const char * const cpuacct_stat_desc[] = { [CPUACCT_STAT_SYSTEM] = "system", }; -struct cpuacct_usage { - u64 usages[CPUACCT_STAT_NSTATS]; -}; - /* track CPU usage of a group of tasks and its child groups */ struct cpuacct { struct cgroup_subsys_state css; /* cpuusage holds pointer to a u64-type object on every CPU */ - struct cpuacct_usage __percpu *cpuusage; + u64 __percpu *cpuusage; struct kernel_cpustat __percpu *cpustat; }; @@ -49,7 +45,7 @@ static inline struct cpuacct *parent_ca(struct cpuacct *ca) return css_ca(ca->css.parent); } -static DEFINE_PER_CPU(struct cpuacct_usage, root_cpuacct_cpuusage); +static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage); static struct cpuacct root_cpuacct = { .cpustat = &kernel_cpustat, .cpuusage = &root_cpuacct_cpuusage, @@ -68,7 +64,7 @@ cpuacct_css_alloc(struct cgroup_subsys_state *parent_css) if (!ca) goto out; - ca->cpuusage = alloc_percpu(struct cpuacct_usage); + ca->cpuusage = alloc_percpu(u64); if (!ca->cpuusage) goto out_free_ca; @@ -99,7 +95,8 @@ static void cpuacct_css_free(struct cgroup_subsys_state *css) static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu, enum cpuacct_stat_index index) { - struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); + u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); + u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat; u64 data; /* @@ -116,14 +113,17 @@ static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu, raw_spin_rq_lock_irq(cpu_rq(cpu)); #endif - if (index == CPUACCT_STAT_NSTATS) { - int i = 0; - - data = 0; - for (i = 0; i < CPUACCT_STAT_NSTATS; i++) - data += cpuusage->usages[i]; - } else { - data = cpuusage->usages[index]; + switch (index) { + case CPUACCT_STAT_USER: + data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE]; + break; + case CPUACCT_STAT_SYSTEM: + data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] + + cpustat[CPUTIME_SOFTIRQ]; + break; + case CPUACCT_STAT_NSTATS: + data = *cpuusage; + break; } #ifndef CONFIG_64BIT @@ -133,10 +133,14 @@ static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu, return data; } -static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) +static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu) { - struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); - int i; + u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); + u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat; + + /* Don't allow to reset global kernel_cpustat */ + if (ca == &root_cpuacct) + return; #ifndef CONFIG_64BIT /* @@ -144,9 +148,10 @@ static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) */ raw_spin_rq_lock_irq(cpu_rq(cpu)); #endif - - for (i = 0; i < CPUACCT_STAT_NSTATS; i++) - cpuusage->usages[i] = val; + *cpuusage = 0; + cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0; + cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0; + cpustat[CPUTIME_SOFTIRQ] = 0; #ifndef CONFIG_64BIT raw_spin_rq_unlock_irq(cpu_rq(cpu)); @@ -197,7 +202,7 @@ static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft, return -EINVAL; for_each_possible_cpu(cpu) - cpuacct_cpuusage_write(ca, cpu, 0); + cpuacct_cpuusage_write(ca, cpu); return 0; } @@ -244,25 +249,10 @@ static int cpuacct_all_seq_show(struct seq_file *m, void *V) seq_puts(m, "\n"); for_each_possible_cpu(cpu) { - struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); - seq_printf(m, "%d", cpu); - - for (index = 0; index < CPUACCT_STAT_NSTATS; index++) { -#ifndef CONFIG_64BIT - /* - * Take rq->lock to make 64-bit read safe on 32-bit - * platforms. - */ - raw_spin_rq_lock_irq(cpu_rq(cpu)); -#endif - - seq_printf(m, " %llu", cpuusage->usages[index]); - -#ifndef CONFIG_64BIT - raw_spin_rq_unlock_irq(cpu_rq(cpu)); -#endif - } + for (index = 0; index < CPUACCT_STAT_NSTATS; index++) + seq_printf(m, " %llu", + cpuacct_cpuusage_read(ca, cpu, index)); seq_puts(m, "\n"); } return 0; @@ -340,16 +330,11 @@ static struct cftype files[] = { void cpuacct_charge(struct task_struct *tsk, u64 cputime) { struct cpuacct *ca; - int index = CPUACCT_STAT_SYSTEM; - struct pt_regs *regs = get_irq_regs() ? : task_pt_regs(tsk); - - if (regs && user_mode(regs)) - index = CPUACCT_STAT_USER; rcu_read_lock(); for (ca = task_ca(tsk); ca; ca = parent_ca(ca)) - __this_cpu_add(ca->cpuusage->usages[index], cputime); + __this_cpu_add(*ca->cpuusage, cputime); rcu_read_unlock(); }