From: "H. Peter Anvin" <hpa@zytor.com>
To: Brian Gerst <brgerst@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Asit K Mallick <asit.k.mallick@intel.com>,
Tony Luck <tony.luck@intel.com>,
Arjan van de Ven <arjan.van.de.ven@intel.com>,
Suresh B Siddha <suresh.b.siddha@intel.com>,
Len Brown <len.brown@intel.com>,
Randy Dunlap <rdunlap@xenotime.net>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Peter Zijlstra <peterz@infradead.org>,
Chen Gong <gong.chen@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-pm <linux-pm@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v5 10/12] x86/mtrr/main.c: Ask the first online CPU to save mtrr
Date: Sun, 15 Jan 2012 16:07:44 -0800 [thread overview]
Message-ID: <4F136A50.80203@zytor.com> (raw)
In-Reply-To: <CAMzpN2hfCCarbn+CDGrQuUaXYT29HpRd+9n0EKWvZdgLdqdAhA@mail.gmail.com>
On 01/12/2012 04:33 AM, Brian Gerst wrote:
> On Wed, Jan 11, 2012 at 12:04 PM, Fenghua Yu <fenghua.yu@intel.com> wrote:
>> From: Fenghua Yu <fenghua.yu@intel.com>
>>
>> Ask the first online CPU to save mtrr instead of asking BSP. BSP could be
>> offline when mtrr_save_state() is called.
>
> If you can use any non-boot cpu to save the MTRRs why not just use the
> current cpu? They should all be in sync anyways.
>
A much bigger question: why do we ever bother saving the MTRR state per
se? We examine the MTRR state -- we have to -- during boot, and it
should never diverge from the state set by the OS from that point on --
we'll need to set it back to that. So we should just keep track of what
the correct MTRR state is at all times.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-01-16 0:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-11 17:04 [PATCH v5 0/12] x86: Arbitrary CPU hot(un)plug support Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 01/12] Documentations/cpu-hotplug.tx, kernel-parameters.txt: Add x86 CPU0 online/offline feature Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 02/12] x86/Kconfig: Add config switch for CPU0 hotplug Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 03/12] x86/topology.c: Support functions for CPU0 online/offline Fenghua Yu
2012-01-16 17:35 ` Ben Hutchings
2012-01-24 22:31 ` Yu, Fenghua
2012-01-24 22:52 ` Ben Hutchings
2012-01-24 23:00 ` Yu, Fenghua
2012-01-11 17:04 ` [PATCH v5 04/12] x86/smpboot.c: Don't offline CPU0 if any irq can not be migrated out of it and remove CPU0 check in smp_callin() Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 05/12] x86/power/cpu.c: Don't hibernate/suspend if CPU0 is offline Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 06/12] x86/head_64.S: Define start_cpu0 Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 07/12] x86/head_32.S: " Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 08/12] x86/smpboot.c: Wake up CPU0 via NMI instead of INITs Fenghua Yu
2012-01-12 12:31 ` Brian Gerst
2012-01-11 17:04 ` [PATCH v5 09/12] x86/common.c: Init CPU0 data during CPU0 online Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 10/12] x86/mtrr/main.c: Ask the first online CPU to save mtrr Fenghua Yu
2012-01-12 12:33 ` Brian Gerst
2012-01-16 0:07 ` H. Peter Anvin [this message]
2012-01-25 17:58 ` Yu, Fenghua
2012-01-25 19:01 ` Yu, Fenghua
2012-01-11 17:04 ` [PATCH v5 11/12] x86/i387.c: Thread xstate is initialized only on CPU0 once Fenghua Yu
2012-01-11 17:04 ` [PATCH v5 12/12] x86/topology.c: debug CPU0 hotplug Fenghua Yu
2012-01-15 15:24 ` Jiang Liu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F136A50.80203@zytor.com \
--to=hpa@zytor.com \
--cc=akpm@linux-foundation.org \
--cc=arjan.van.de.ven@intel.com \
--cc=asit.k.mallick@intel.com \
--cc=brgerst@gmail.com \
--cc=fenghua.yu@intel.com \
--cc=gong.chen@linux.intel.com \
--cc=konrad.wilk@oracle.com \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
--cc=rdunlap@xenotime.net \
--cc=srivatsa.bhat@linux.vnet.ibm.com \
--cc=suresh.b.siddha@intel.com \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).