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From: Qais Yousef <qais.yousef@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: valentin.schneider@arm.com, tglx@linutronix.de, mingo@kernel.org,
	bigeasy@linutronix.de, swood@redhat.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vincent.donnefort@arm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] cpumask: Introduce DYING mask
Date: Sun, 21 Mar 2021 19:30:37 +0000	[thread overview]
Message-ID: <20210321193037.7o3mqcmwjthbos7n@e107158-lin> (raw)
In-Reply-To: <20210310150109.151441252@infradead.org>

On 03/10/21 15:53, Peter Zijlstra wrote:
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -160,6 +160,9 @@ static int cpuhp_invoke_callback(unsigne
>  	int (*cb)(unsigned int cpu);
>  	int ret, cnt;
>  
> +	if (bringup != !cpu_dying(cpu))

nit: this condition is hard to read

> +		set_cpu_dying(cpu, !bringup);

since cpu_dying() will do cpumask_test_cpu(), are we saving  much if we
unconditionally call set_cpu_dying(cpu, !bringup) which performs
cpumask_{set, clear}_cpu()?

> +
>  	if (st->fail == state) {
>  		st->fail = CPUHP_INVALID;
>  		return -EAGAIN;

Thanks

--
Qais yousef

  reply	other threads:[~2021-03-21 19:38 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-10 14:52 [PATCH 0/3] sched: Fix remaining balance_push vs hotplug hole Peter Zijlstra
2021-03-10 14:52 ` [PATCH 1/3] cpumask: Make cpu_{online,possible,present,active}() inline Peter Zijlstra
2021-04-16 15:53   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-03-10 14:53 ` [PATCH 2/3] cpumask: Introduce DYING mask Peter Zijlstra
2021-03-21 19:30   ` Qais Yousef [this message]
2021-03-22 15:07     ` Steven Rostedt
2021-04-12 10:55     ` Peter Zijlstra
2021-04-12 11:16       ` Qais Yousef
2021-04-16 15:53   ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-03-10 14:53 ` [PATCH 3/3] sched: Use cpu_dying() to fix balance_push vs hotplug-rollback Peter Zijlstra
2021-03-11 15:13   ` Valentin Schneider
2021-03-11 16:42     ` Peter Zijlstra
2021-04-12 12:03     ` Peter Zijlstra
2021-04-12 17:22       ` Valentin Schneider
2021-04-13  6:51         ` Peter Zijlstra
2021-04-15  8:59           ` Peter Zijlstra
2021-04-15 14:32             ` Valentin Schneider
2021-04-15 15:29               ` Peter Zijlstra
2021-04-15 15:34                 ` Valentin Schneider
2021-04-19 10:56               ` Vincent Donnefort
2021-04-20  9:46                 ` Vincent Donnefort
2021-04-20 14:20                   ` Peter Zijlstra
2021-04-20 14:39                     ` Peter Zijlstra
2021-04-20 14:58                       ` Peter Zijlstra
2021-04-20 16:53                         ` Vincent Donnefort
2021-04-20 18:07                           ` Peter Zijlstra
2021-04-21  9:32                         ` Valentin Schneider
2021-04-22  7:36                         ` [tip: sched/core] cpumask/hotplug: Fix cpu_dying() state tracking tip-bot2 for Peter Zijlstra
2021-04-16 15:53             ` [tip: sched/core] sched: Use cpu_dying() to fix balance_push vs hotplug-rollback tip-bot2 for Peter Zijlstra

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