From: Rik van Riel <riel@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Wanpeng Li" <wanpeng.li@hotmail.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Frederic Weisbecker" <fweisbec@gmail.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH v5 3/3] sched/cputime: Add steal time support to full dynticks CPU time accounting
Date: Wed, 08 Jun 2016 15:05:00 -0400 [thread overview]
Message-ID: <1465412700.4639.10.camel@redhat.com> (raw)
In-Reply-To: <1465355110-21714-3-git-send-email-wanpeng.li@hotmail.com>
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On Wed, 2016-06-08 at 11:05 +0800, Wanpeng Li wrote:
>
> @@ -681,12 +681,17 @@ static cputime_t vtime_delta(struct task_struct
> *tsk)
> static cputime_t get_vtime_delta(struct task_struct *tsk)
> {
> unsigned long now = READ_ONCE(jiffies);
> - unsigned long delta = now - tsk->vtime_snap;
> + cputime_t delta_time, steal_time;
>
> + steal_time =
> jiffies_to_cputime(steal_account_process_tick());
> + delta_time = jiffies_to_cputime(now - tsk->vtime_snap);
> WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE);
> tsk->vtime_snap = now;
>
> - return jiffies_to_cputime(delta);
> + if (steal_time < delta_time)
> + delta_time -= steal_time;
> +
> + return delta_time;
> }
This isn't right.
If steal_time is equal to or larger than delta_time,
get_vtime_delta needs to return 0, not delta_time.
Otherwise the same time will be counted twice.
--
All rights reversed
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next prev parent reply other threads:[~2016-06-08 19:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-08 3:05 [PATCH v5 1/3] KVM: fix steal clock warp during guest cpu hotplug Wanpeng Li
2016-06-08 3:05 ` [PATCH v5 2/3] sched/cputime: Fix prev steal time accouting during " Wanpeng Li
2016-06-08 10:01 ` Paolo Bonzini
2016-06-08 10:59 ` Wanpeng Li
2016-06-08 3:05 ` [PATCH v5 3/3] sched/cputime: Add steal time support to full dynticks CPU time accounting Wanpeng Li
2016-06-08 7:22 ` Ingo Molnar
2016-06-08 7:27 ` Wanpeng Li
2016-06-08 7:52 ` Ingo Molnar
2016-06-08 8:04 ` Wanpeng Li
2016-06-08 8:12 ` Wanpeng Li
2016-06-08 10:14 ` Paolo Bonzini
2016-06-08 11:11 ` Wanpeng Li
2016-06-13 3:38 ` Wanpeng Li
2016-06-13 7:55 ` Paolo Bonzini
2016-06-13 8:09 ` Wanpeng Li
2016-06-08 19:05 ` Rik van Riel [this message]
2016-06-08 23:57 ` Wanpeng Li
2016-06-09 1:20 ` Rik van Riel
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