Date: Wed, 15 Jul 2015 18:06:25 -0400
From: Tejun Heo <tj@kernel.org>
To: Tang Chen <tangchen@cn.fujitsu.com>
Cc: mingo@redhat.com, akpm@linux-foundation.org, rjw@rjwysocki.net,
        hpa@zytor.com, laijs@cn.fujitsu.com, yasu.isimatu@gmail.com,
        isimatu.yasuaki@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com,
        izumi.taku@jp.fujitsu.com, gongzhaogang@inspur.com,
        qiaonuohan@cn.fujitsu.com, x86@kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Gu Zheng <guz.fnst@cn.fujitsu.com>
Subject: Re: [PATCH 4/5] x86, acpi, cpu-hotplug: Enable MADT APIs to return
 disabled apicid.
Message-ID: <20150715220625.GN15934@mtj.duckdns.org>
References: <1436261425-29881-1-git-send-email-tangchen@cn.fujitsu.com>
 <1436261425-29881-5-git-send-email-tangchen@cn.fujitsu.com>
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Hello,

On Tue, Jul 07, 2015 at 05:30:24PM +0800, Tang Chen wrote:
> From: Gu Zheng <guz.fnst@cn.fujitsu.com>
> 
> All processors' apicids can be obtained by _MAT method or from MADT in ACPI.
> The current code ignores disabled processors and returns -ENODEV.
> 
> After this patch, a new parameter will be added to MADT APIs so that caller
> is able to control if disabled processors are ignored.

This describes what the patch does but doesn't really explain what the
patch is trying to achieve.

> @@ -282,8 +282,11 @@ static int acpi_processor_get_info(struct acpi_device *device)
>  	 *  Extra Processor objects may be enumerated on MP systems with
>  	 *  less than the max # of CPUs. They should be ignored _iff
>  	 *  they are physically not present.
> +	 *
> +	 *  NOTE: Even if the processor has a cpuid, it may not present because
                                                               ^
							       be
> +	 *  cpuid <-> apicid mapping is persistent now.

Saying "now" is kinda weird as this is how the code is gonna be
forever.

Thanks.

-- 
tejun
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