linux-kernel - Re: [Patch v3 2/2] x86/acpi: Remove the repeated lapic address override entry parsing

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Date:	Thu, 11 Aug 2016 22:21:27 +0800
From:	Baoquan He <bhe@...hat.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	rjw@...ysocki.net, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [Patch v3 2/2] x86/acpi: Remove the repeated lapic address
 override entry parsing

On 08/11/16 at 10:37am, Ingo Molnar wrote:
> 
> * Baoquan He <bhe@...hat.com> wrote:
> 
> > On 08/10/16 at 04:02pm, Ingo Molnar wrote:
> > > 
> > > * Baoquan He <bhe@...hat.com> wrote:
> > > 
> > > > ACPI MADT has a 32-bit field providing lapic address at which
> > > > each processor can access its lapic information. MADT also contains
> > > > an optional entry to provide a 64-bit address to override the 32-bit
> > > > one. However the current code does the lapic address override entry
> > > > parsing twice. One is in early_acpi_boot_init() because AMD NUMA need
> > > > get boot_cpu_id earlier. The other is in acpi_boot_init() which parses
> > > > all MADT entries.
> > > > 
> > > > So in this patch remove the repeated code in the 2nd part. Meanwhile
> > > > print lapic override entry information like other MADT entry, this
> > > > will be added to boot log.
> > > 
> > > it is not at all clear to me from this changelog whether the change is supposed to 
> > > change anything. If not then please spell it out explicitly:
> > > 
> > >   "This patch is not supposed to change any behavior."
> > 
> > I don't know if adding new information to boot log can be seen as
> > behavior change. If lapic override entry exist, the code change will
> > add one line of message to boot log:
> > 
> > 	LAPIC_ADDR_OVR (address[0xXXXXXXXX])
> > 
> > If this is not behavior change, I will add the sentence you suggested.
> 
> Yeah, you can write it:
> 
> 	"This patch is not supposed to change any runtime behavior, other than 
> 	 improving kernel messages."

Got it, will copy this to patch log and repost. Thanks a lot!

Thanks
Baoquan