From: Tejun Heo <tj@kernel.org>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: tglx@linutronix.de, peterz@infradead.org,
paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au,
mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org,
vincent.guittot@linaro.org, sbw@mit.edu,
amit.kucheria@linaro.org, rostedt@goodmis.org, rjw@sisk.pl,
wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com,
nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 01/10] CPU hotplug: Introduce "stable" cpu online mask, for atomic hotplug readers
Date: Tue, 4 Dec 2012 07:17:34 -0800 [thread overview]
Message-ID: <20121204151734.GB3885@mtj.dyndns.org> (raw)
In-Reply-To: <20121204085324.25919.53090.stgit@srivatsabhat.in.ibm.com>
Hello, Srivatsa.
On Tue, Dec 04, 2012 at 02:23:41PM +0530, Srivatsa S. Bhat wrote:
> extern const struct cpumask *const cpu_possible_mask;
> extern const struct cpumask *const cpu_online_mask;
> +extern const struct cpumask *const cpu_online_stable_mask;
> extern const struct cpumask *const cpu_present_mask;
> extern const struct cpumask *const cpu_active_mask;
This is a bit nasty. The distinction between cpu_online_mask and the
stable one is quite subtle and there's no mechanism to verify the
right one is in use. IIUC, the only time cpu_online_mask and
cpu_online_stable_mask can deviate is during the final stage CPU take
down, right? If so, why not just make cpu_online_mask the stable one
and the few cases where the actual online state matters deal with the
internal version? Anyone outside cpu hotplug proper should be happy
with the stable version anyway, no?
Thanks.
--
tejun
next prev parent reply other threads:[~2012-12-04 15:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-04 8:53 [RFC PATCH 00/10] CPU hotplug: stop_machine()-free CPU hotplug Srivatsa S. Bhat
2012-12-04 8:53 ` [RFC PATCH 01/10] CPU hotplug: Introduce "stable" cpu online mask, for atomic hotplug readers Srivatsa S. Bhat
2012-12-04 15:17 ` Tejun Heo [this message]
2012-12-04 21:14 ` Srivatsa S. Bhat
2012-12-04 22:10 ` Andrew Morton
2012-12-05 2:56 ` Michael Wang
2012-12-05 3:28 ` Michael Wang
2012-12-05 12:38 ` Srivatsa S. Bhat
2012-12-04 8:54 ` [RFC PATCH 02/10] smp, cpu hotplug: Fix smp_call_function_*() to prevent CPU offline properly Srivatsa S. Bhat
2012-12-04 22:17 ` Andrew Morton
2012-12-05 12:41 ` Srivatsa S. Bhat
2012-12-04 23:39 ` Rusty Russell
2012-12-05 12:44 ` Srivatsa S. Bhat
2012-12-04 8:54 ` [RFC PATCH 03/10] smp, cpu hotplug: Fix on_each_cpu_*() " Srivatsa S. Bhat
2012-12-04 8:54 ` [RFC PATCH 04/10] sched, cpu hotplug: Use stable online cpus in try_to_wake_up() & select_task_rq() Srivatsa S. Bhat
2012-12-04 8:55 ` [RFC PATCH 05/10] kick_process(), cpu-hotplug: Prevent offlining of target CPU properly Srivatsa S. Bhat
2012-12-04 8:55 ` [RFC PATCH 06/10] yield_to(), cpu-hotplug: Prevent offlining of other CPUs properly Srivatsa S. Bhat
2012-12-04 8:55 ` [RFC PATCH 07/10] KVM: VMX: fix invalid cpu passed to smp_call_function_single Srivatsa S. Bhat
2012-12-04 8:55 ` [RFC PATCH 08/10] KVM: VMX: fix memory order between loading vmcs and clearing vmcs Srivatsa S. Bhat
2012-12-04 8:56 ` [RFC PATCH 09/10] KVM: VMX: fix unsyc vmcs status when cpu is going down Srivatsa S. Bhat
2012-12-04 8:56 ` [RFC PATCH 10/10] cpu: No more __stop_machine() in _cpu_down() Srivatsa S. Bhat
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