From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v2 1/2] x86/msr: Carry on after a non-"safe"
 MSR access fails without !panic_on_oops
Date: Wed, 30 Sep 2015 11:32:00 -0700
Message-ID: <560C2AA0.5040708__42723.6930154779$1443638076$gmane$org@zytor.com>
References: <cover.1442793572.git.luto@kernel.org>
	<130a3b7ef4788baae3a6fe71293ab17442bc9a0a.1442793572.git.luto@kernel.org>
	<CA+55aFy4Chd-PJvxGne=TztPsvFqUG07Ht8mtc4+0oGNZNDOyw@mail.gmail.com>
	<CALCETrXqsKcqzfqMO2ctOJJ4X8Kb6vvoUpVDir9F2-a3XwK23w@mail.gmail.com>
	<20150921084642.GA30984@gmail.com>
	<CA+55aFzKCi6pf0RP8HjDQYDsms6reB5AihuCAHEkVJtoOHk_Yw@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <CA+55aFzKCi6pf0RP8HjDQYDsms6reB5AihuCAHEkVJtoOHk_Yw@mail.gmail.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Linus Torvalds <torvalds@linux-foundation.org>, Ingo Molnar <mingo@kernel.org>
Cc: KVM list <kvm@vger.kernel.org>, Peter Zijlstra <peterz@infradead.org>, the arch/x86 maintainers <x86@kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, xen-devel <Xen-devel@lists.xen.org>, Paolo Bonzini <pbonzini@redhat.com>, Thomas Gleixner <tglx@linutronix.de>, Andy Lutomirski <luto@amacapital.net>, Arjan van de Ven <arjan@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>
List-Id: xen-devel@lists.xenproject.org

On 09/21/2015 09:36 AM, Linus Torvalds wrote:
> 
> How many msr reads are <i>so</i> critical that the function call
> overhead would matter? Get rid of the inline version of the _safe()
> thing too, and put that thing there too.
> 

Probably only the ones that may go in the context switch path.

	-hpa