From: Rob Landley <rob@landley.net>
To: Hsin-Yi Wang <hsinyi@chromium.org>, Thomas Gleixner <tglx@linutronix.de>
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>,
Aaro Koskinen <aaro.koskinen@nokia.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Will Deacon <will@kernel.org>, Fenghua Yu <fenghua.yu@intel.com>,
James Morse <james.morse@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Guenter Roeck <groeck@chromium.org>,
Stephen Boyd <swboyd@chromium.org>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org,
linux-pm@vger.kernel.org
Subject: Re: [PATCH RESEND v4] reboot: support offline CPUs before reboot
Date: Thu, 16 Jan 2020 22:20:28 -0600 [thread overview]
Message-ID: <a701522f-73aa-2277-4a25-f84a27f38118@landley.net> (raw)
In-Reply-To: <20200114110620.164861-1-hsinyi@chromium.org>
On 1/14/20 5:06 AM, Hsin-Yi Wang wrote:
> This patch adds a config ARCH_OFFLINE_CPUS_ON_REBOOT, which would offline cpus in
> migrate_to_reboot_cpu(). If non reboot cpus are all offlined here, the loop for
> checking online cpus would be an empty loop. If architecture don't enable this
> config, or some cpus somehow fails to offline, it would fallback to ipi
> function.
I'm curious:
> +# Select to do a full offline on secondary CPUs before reboot.
> +config ARCH_OFFLINE_CPUS_ON_REBOOT
> + bool "Support for offline CPUs before reboot"
> + depends on HOTPLUG_CPU
The new symbol can't be selected without the other symbol.
> + select ARCH_OFFLINE_CPUS_ON_REBOOT if HOTPLUG_CPU
And the other symbol automatically selects the new one.
Why are you adding a second symbol that means the same thing as the existing symbol?
> +#if defined(CONFIG_PM_SLEEP_SMP) || defined(CONFIG_ARCH_OFFLINE_CPUS_ON_REBOOT)
> +extern int freeze_secondary_cpus(int primary, bool reboot);
> +#endif
Couldn't that just test HOTPLUG_CPU? What's the second symbol for? (You can have
empty stub functions when architectures don't support a thing...)
Rob
next prev parent reply other threads:[~2020-01-17 4:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 11:06 [PATCH RESEND v4] reboot: support offline CPUs before reboot Hsin-Yi Wang
2020-01-14 13:54 ` Guenter Roeck
2020-01-14 16:19 ` Thomas Gleixner
2020-01-17 4:20 ` Rob Landley [this message]
2020-01-17 4:20 ` Hsin-Yi Wang
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