From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1034103AbbKEGqO (ORCPT <rfc822;w@1wt.eu>);
	Thu, 5 Nov 2015 01:46:14 -0500
Received: from mail-ig0-f180.google.com ([209.85.213.180]:36232 "EHLO
	mail-ig0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1034074AbbKEGqD (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 5 Nov 2015 01:46:03 -0500
MIME-Version: 1.0
In-Reply-To: <20151105063813.GA12730@gmail.com>
References: <20151104215716.810356093@linutronix.de>
	<20151104220848.817975597@linutronix.de>
	<20151105063813.GA12730@gmail.com>
Date: Wed, 4 Nov 2015 22:46:01 -0800
X-Google-Sender-Auth: VlPd57WxXB13E3SNdX2c6aFCxko
Message-ID: <CA+55aFzGFmGzytS_kDfs8FF=zZ2Y2sXpMNbY+g6EgVfwWEyaBw@mail.gmail.com>
Subject: Re: [patch 02/14] x86/apic: Implement single target IPI function for x2apic_cluster
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, LKML <linux-kernel@vger.kernel.org>,
        Peter Anvin <hpa@zytor.com>, Borislav Petkov <borislav.petkov@amd.com>,
        Peter Zijlstra <peterz@infradead.org>, Mike Travis <travis@sgi.com>,
        Daniel J Blueman <daniel@numascale.com>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Nov 4, 2015 at 10:38 PM, Ingo Molnar <mingo@kernel.org> wrote:
>
> but in the above sequence I think we can do even better: we don't need the
> local_irq_save()/restore() I think.

Right. Thomas added that one to my patch.

I don't think he realized just *how* trivial sending a single IPI is
with the x2apic, and just how horribly nasty the mask case is in
comparison (and how nasty it is that we historically turn a the single
ipi into a mask).

              Linus