From: "H. Peter Anvin" <hpa@zytor.com>
To: Josh Boyer <jwboyer@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
mingo@redhat.com, tglx@linutronix.de, konrad.wilk@oracle.com,
rostedt@goodmis.org, gregkh@linuxfoundation.org,
samu.kallio@aberdeencloud.com, kraman@redhat.com,
xen-devel@lists.xen.org, linux-kernel@vger.kernel.org,
stable@kernel.org
Subject: Re: [PATCH] mm/x86: Patch out arch_flush_lazy_mmu_mode() when running on bare metal
Date: Thu, 28 Feb 2013 16:15:45 -0800 [thread overview]
Message-ID: <512FF331.5050008@zytor.com> (raw)
In-Reply-To: <20130301000539.GA31649@hansolo.jdub.homelinux.org>
On 02/28/2013 04:05 PM, Josh Boyer wrote:
> On Fri, Mar 01, 2013 at 12:37:20AM +0100, Borislav Petkov wrote:
>> On Thu, Feb 28, 2013 at 05:55:49PM -0500, Boris Ostrovsky wrote:
>>> Invoking arch_flush_lazy_mmu_mode() results in calls to
>>> preempt_enable()/disable() which may have performance impact.
>>>
>>> Since lazy MMU is not used on bare metal we can patch away
>>> arch_flush_lazy_mmu_mode() so that it is never called in such
>>> environment.
>>>
>>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>>
>> Looks straight-forward enough to me.
>>
>> Acked-by: Borislav Petkov <bp@suse.de>
>
> I'll try to get someone to test this tomorrow.
>
Sounds good.
I'd like look at this after the merge window close. I'm kind of
bothered about having a choice with an oops on PV, a performance
regression on native, or putting a pretty complex patch in as a fix, but
since we'll be right after -rc1 it is probably reasonable to pick the
last option.
-hpa
next prev parent reply other threads:[~2013-03-01 0:17 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-28 22:55 [PATCH] mm/x86: Patch out arch_flush_lazy_mmu_mode() when running on bare metal Boris Ostrovsky
2013-02-28 23:37 ` Borislav Petkov
2013-02-28 23:37 ` Borislav Petkov
2013-03-01 0:05 ` Josh Boyer
2013-03-01 0:15 ` H. Peter Anvin
2013-03-01 0:15 ` H. Peter Anvin [this message]
2013-03-01 0:36 ` Borislav Petkov
2013-03-01 0:42 ` Josh Boyer
2013-03-01 0:52 ` H. Peter Anvin
2013-03-01 0:52 ` H. Peter Anvin
2013-03-01 12:14 ` Josh Boyer
2013-03-13 13:25 ` Boris Ostrovsky
2013-03-13 13:44 ` Josh Boyer
2013-03-13 13:44 ` Josh Boyer
2013-03-21 14:07 ` Konrad Rzeszutek Wilk
2013-03-21 14:07 ` Konrad Rzeszutek Wilk
2013-03-21 14:39 ` Stefan Bader
2013-03-22 1:11 ` Konrad Rzeszutek Wilk
2013-03-13 13:25 ` Boris Ostrovsky
2013-03-01 12:14 ` Josh Boyer
2013-03-01 0:42 ` Josh Boyer
2013-03-01 0:36 ` Borislav Petkov
2013-03-01 0:05 ` Josh Boyer
2013-03-04 15:13 ` Konrad Rzeszutek Wilk
2013-03-04 15:13 ` Konrad Rzeszutek Wilk
-- strict thread matches above, loose matches on Subject: below --
2013-02-28 22:55 Boris Ostrovsky
2013-03-20 13:53 Boris Ostrovsky
2013-03-20 13:53 Boris Ostrovsky
2013-03-21 0:08 ` Josh Boyer
2013-03-22 20:09 ` Konrad Rzeszutek Wilk
2013-03-22 20:25 ` H. Peter Anvin
2013-03-22 20:25 ` H. Peter Anvin
2013-03-22 20:09 ` Konrad Rzeszutek Wilk
2013-03-21 0:08 ` Josh Boyer
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