From: "Li,Rongqing" <lirongqing@baidu.com>
To: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"juri.lelli@redhat.com" <juri.lelli@redhat.com>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"bsegall@google.com" <bsegall@google.com>,
"mgorman@suse.de" <mgorman@suse.de>,
"bristot@redhat.co" <bristot@redhat.co>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"songmuchun@bytedance.com" <songmuchun@bytedance.com>,
"Michal Koutný" <mkoutny@suse.com>
Subject: 答复: 答复: [PATCH][RFC] sched/cpuacct: Fix cpuacct charge
Date: Tue, 17 Aug 2021 03:55:08 +0000 [thread overview]
Message-ID: <06265d4d0df7410786d0ddb9bdbc4e4c@baidu.com> (raw)
In-Reply-To: <20210816162103.dup2hbho24wtmsgs@oracle.com>
> > diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index
> > 893eece..48b117e 100644
> > --- a/kernel/sched/cpuacct.c
> > +++ b/kernel/sched/cpuacct.c
> > @@ -340,7 +340,12 @@ 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);
> > + struct pt_regs *regs;
> > +
> > + if (task_cpu(tsk) == raw_smp_processor_id())
> > + regs = get_irq_regs() ? : task_pt_regs(tsk);
> > + else
> > + regs = task_pt_regs(tsk);
> >
> > if (regs && user_mode(regs))
> > index = CPUACCT_STAT_USER;
>
> It still suffers from task_pt_regs().
>
> Why not make cpuacct use cgroup2's approach? Remember only delta_exec
> here, then on reading cpuacct.usage_*, use cputime_adjust() to scale the
> user/sys from cpuacct_account_field().
>
I think your suggestion is reasonable, Could you send a patch
> It's arguably more than just a fix for cgroup1, but there have been a few
> complaints about this function lately.
>
> > rcu_read_lock();
> >
> > for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
> > __this_cpu_add(ca->cpuusage->usages[index], cputime);
> >
> > rcu_read_unlock();
>
> By the way, I think the __this_cpu_add() can be wrong in cases like you originally
> describe. Seems like a bug in 73e6aafd9ea8 ("sched/cpuacct:
> Simplify the cpuacct code").
We find this issue too.
-Li
next prev parent reply other threads:[~2021-08-17 3:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-20 6:04 [PATCH][RFC] sched/cpuacct: Fix cpuacct charge Li RongQing
2021-07-29 10:19 ` Peter Zijlstra
2021-07-30 8:16 ` 答复: " Li,Rongqing
2021-08-16 16:21 ` Daniel Jordan
2021-08-17 3:55 ` Li,Rongqing [this message]
2021-08-18 15:33 ` 答复: " Daniel Jordan
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