Re: [PATCH v7 01/16] ACPI: processor: Simplify initial onlining to use same path for cold and hotplug

From: Gavin Shan <gshan@redhat.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-pm@vger.kernel.org, loongarch@lists.linux.dev,
	linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	x86@kernel.org, Russell King <linux@armlinux.org.uk>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Miguel Luis <miguel.luis@oracle.com>,
	James Morse <james.morse@arm.com>,
	Salil Mehta <salil.mehta@huawei.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linuxarm@huawei.com, justin.he@arm.com, jianyong.wu@arm.com
Subject: Re: [PATCH v7 01/16] ACPI: processor: Simplify initial onlining to use same path for cold and hotplug
Date: Fri, 26 Apr 2024 19:23:19 +1000	[thread overview]
Message-ID: <566817ae-90f0-4ec9-b54e-b9fdb635119e@redhat.com> (raw)
In-Reply-To: <20240418135412.14730-2-Jonathan.Cameron@huawei.com>

On 4/18/24 23:53, Jonathan Cameron wrote:
> Separate code paths, combined with a flag set in acpi_processor.c to
> indicate a struct acpi_processor was for a hotplugged CPU ensured that
> per CPU data was only set up the first time that a CPU was initialized.
> This appears to be unnecessary as the paths can be combined by letting
> the online logic also handle any CPUs online at the time of driver load.
> 
> Motivation for this change, beyond simplification, is that ARM64
> virtual CPU HP uses the same code paths for hotplug and cold path in
> acpi_processor.c so had no easy way to set the flag for hotplug only.
> Removing this necessity will enable ARM64 vCPU HP to reuse the existing
> code paths.
> 
> Leave noisy pr_info() in place but update it to not state the CPU
> was hotplugged.
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> ---
> v7: No change.
> v6: New patch.
> RFT: I have very limited test resources for x86 and other
> architectures that may be affected by this change.
> ---
>   drivers/acpi/acpi_processor.c   |  1 -
>   drivers/acpi/processor_driver.c | 44 ++++++++++-----------------------
>   include/acpi/processor.h        |  2 +-
>   3 files changed, 14 insertions(+), 33 deletions(-)
> 

Reviewed-by: Gavin Shan <gshan@redhat.com>