From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752206AbbIGUpW (ORCPT ); Mon, 7 Sep 2015 16:45:22 -0400 Received: from mail-ig0-f179.google.com ([209.85.213.179]:38001 "EHLO mail-ig0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871AbbIGUpT (ORCPT ); Mon, 7 Sep 2015 16:45:19 -0400 MIME-Version: 1.0 In-Reply-To: <20150907065703.GX3644@twins.programming.kicks-ass.net> References: <20150904054820.GY3902@dastard> <20150904071143.GZ3902@dastard> <20150904082954.GB3902@dastard> <20150904151427.GG18489@twins.programming.kicks-ass.net> <20150904152523.GR18673@twins.programming.kicks-ass.net> <20150907000546.GA27993@linux-q0g1.site> <20150907065703.GX3644@twins.programming.kicks-ass.net> Date: Mon, 7 Sep 2015 13:45:18 -0700 X-Google-Sender-Auth: 5DqqWJEL6ZM3nD368xg9Jgnu6ew Message-ID: Subject: Re: [4.2, Regression] Queued spinlocks cause major XFS performance regression From: Linus Torvalds To: Peter Zijlstra Cc: Davidlohr Bueso , Dave Chinner , Linux Kernel Mailing List , Waiman Long , Ingo Molnar Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 6, 2015 at 11:57 PM, Peter Zijlstra wrote: > > Just to continue the argument for arguments sake, the function is named > 'virt' (not paravirt) and tests the HYPERVISOR CPUID bit. How is that > not appropriately named? Well, I think right now one issue is that you can't avoid it, even when you want pure "raw hardware" spinlocks. I really think it should at the very least be inside CONFIG_PARAVIRT. Because it *is* about helping the hypervisor, so really is about paravirtualization. So naming is misleading, I think, and the config option situation is not great. If you act differently under virtualization than you do on raw hardware, what would you call that? I'd call it "paravirt". Linus