From: Shrikanth Hegde <sshegde@linux.ibm.com>
To: Yury Norov <yury.norov@gmail.com>, peterz@infradead.org
Cc: mingo@redhat.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, tglx@linutronix.de,
maddy@linux.ibm.com, vschneid@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
jstultz@google.com, kprateek.nayak@amd.com,
huschle@linux.ibm.com, srikar@linux.ibm.com,
linux-kernel@vger.kernel.org, linux@rasmusvillemoes.dk
Subject: Re: [RFC PATCH 1/5] cpumask: Introduce cpu parked mask
Date: Mon, 23 Jun 2025 13:40:00 +0530 [thread overview]
Message-ID: <d916d3ae-afd4-4f07-a6e8-941a71cc039e@linux.ibm.com> (raw)
In-Reply-To: <aDXU6LUlrmBLL3ak@yury>
On 5/27/25 20:36, Yury Norov wrote:
> On Fri, May 23, 2025 at 11:44:44PM +0530, Shrikanth Hegde wrote:
>> CPU is said to be parked, when underlying physical CPU is not
>> available. This happens when there is contention for CPU resource in
>> para-virtualized case. One should avoid using these CPUs.
>>
>> Build and maintain this state of parked CPUs. Scheduler will use this
>> information and push the tasks out as soon as it can.
>
> This 'parked' term sounds pretty obscured. Maybe name it in
> a positive sense, and more explicit, like cpu_paravirt_mask.
>
I still dont know a better name. Maybe something like cpu_avoid_mask and
cpu avoid(cpu)? I would like to retain a notion that these CPU shouldn't be used
at the moment.
> Also, shouldn't this be conditional on CONFIG_PARAVIRT?
>
I moved the uses of it under a static key which should make it a nop for
others. That keeps code relatively simpler. Hope that's ok.
> Thanks,
> Yury
>
next prev parent reply other threads:[~2025-06-23 8:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-23 18:14 [RFC PATCH 0/5] sched: cpu parked and push current task mechanism Shrikanth Hegde
2025-05-23 18:14 ` [RFC PATCH 1/5] cpumask: Introduce cpu parked mask Shrikanth Hegde
2025-05-27 15:06 ` Yury Norov
2025-06-23 8:10 ` Shrikanth Hegde [this message]
2025-05-23 18:14 ` [RFC PATCH 2/5] sched/core: Don't use parked cpu for selection Shrikanth Hegde
2025-05-27 14:59 ` Yury Norov
2025-05-27 17:35 ` Shrikanth Hegde
2025-05-23 18:14 ` [RFC PATCH 3/5] sched/fair: Don't use parked cpu for load balancing Shrikanth Hegde
2025-05-23 18:14 ` [RFC PATCH 4/5] sched/core: Push current task when cpu is parked Shrikanth Hegde
2025-05-23 18:14 ` [DEBUG PATCH 5/5] powerpc: Use manual hint for cpu parking Shrikanth Hegde
2025-05-27 15:10 ` [RFC PATCH 0/5] sched: cpu parked and push current task mechanism Peter Zijlstra
2025-05-27 15:47 ` Yury Norov
2025-05-27 17:30 ` Shrikanth Hegde
2025-06-02 4:25 ` Shrikanth Hegde
2025-06-02 14:22 ` Tobias Huschle
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