From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932633AbbIDPy4 (ORCPT ); Fri, 4 Sep 2015 11:54:56 -0400 Received: from casper.infradead.org ([85.118.1.10]:36352 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759432AbbIDPyy (ORCPT ); Fri, 4 Sep 2015 11:54:54 -0400 Date: Fri, 4 Sep 2015 17:54:48 +0200 From: Peter Zijlstra To: Linus Torvalds Cc: Dave Chinner , Linux Kernel Mailing List , Waiman Long , Ingo Molnar Subject: Re: [4.2, Regression] Queued spinlocks cause major XFS performance regression Message-ID: <20150904155448.GS18673@twins.programming.kicks-ass.net> References: <20150904054820.GY3902@dastard> <20150904071143.GZ3902@dastard> <20150904082954.GB3902@dastard> <20150904151427.GG18489@twins.programming.kicks-ass.net> <20150904153035.GH18489@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150904153035.GH18489@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 04, 2015 at 05:30:35PM +0200, Peter Zijlstra wrote: > Should I place the virt_spin_lock() thing under CONFIG_PARAVIRT (maybe > even _SPINLOCKS) such that only paravirt enabled kernels when ran on a > hypervisor that does not support paravirt patching (HyperV, VMware, > etc..) revert to the test-and-set? Ah, CONFIG_HYPERVISOR_GUEST seems fitting, that's a prerequisite for all the PARAVIRT options too.