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From: Thomas Gleixner <tglx@linutronix.de>
To: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Jiri Kosina <jkosina@suse.cz>,
	Pavankumar Kondeti <pkondeti@codeaurora.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Zhenzhong Duan <zhenzhong.duan@oracle.com>,
	Aaro Koskinen <aaro.koskinen@nokia.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Guenter Roeck <groeck@chromium.org>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC v2] reboot: hotplug cpus in migrate_to_reboot_cpu()
Date: Thu, 09 Jan 2020 21:15:40 +0100	[thread overview]
Message-ID: <87blrcbd3n.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20191009232655.48583-1-hsinyi@chromium.org>

Hsin-Yi Wang <hsinyi@chromium.org> writes:

> @@ -220,8 +221,6 @@ void migrate_to_reboot_cpu(void)
>  	/* The boot cpu is always logical cpu 0 */
>  	int cpu = reboot_cpu;
>  
> -	cpu_hotplug_disable();
> -
>  	/* Make certain the cpu I'm about to reboot on is online */
>  	if (!cpu_online(cpu))
>  		cpu = cpumask_first(cpu_online_mask);
> @@ -231,6 +230,11 @@ void migrate_to_reboot_cpu(void)
>  
>  	/* Make certain I only run on the appropriate processor */
>  	set_cpus_allowed_ptr(current, cpumask_of(cpu));
> +
> +	/* Hotplug other cpus if possible */
> +#ifdef CONFIG_HOTPLUG_CPU
> +	offline_secondary_cpus(cpu);
> +#endif

In general I like the idea, but shouldn't this remove the architecture
code as a follow up?

Also this needs to be explicitely enabled per architecture (opt-in) and
not as an unconditional operation for all architectures which support
CPU hotplug.

Thanks,

        tglx

  reply	other threads:[~2020-01-09 20:15 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09 23:26 [PATCH RFC v2] reboot: hotplug cpus in migrate_to_reboot_cpu() Hsin-Yi Wang
2020-01-09 20:15 ` Thomas Gleixner [this message]
2020-01-10 10:58   ` Hsin-Yi Wang

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