Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754017AbZAIRlh (ORCPT ); Fri, 9 Jan 2009 12:41:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752524AbZAIRl0 (ORCPT ); Fri, 9 Jan 2009 12:41:26 -0500 Received: from twin.jikos.cz ([213.151.79.26]:34805 "EHLO twin.jikos.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751900AbZAIRlZ (ORCPT ); Fri, 9 Jan 2009 12:41:25 -0500 Date: Fri, 9 Jan 2009 18:40:31 +0100 (CET) From: Jiri Kosina X-X-Sender: jikos@twin.jikos.cz To: Peter Zijlstra cc: Linus Torvalds , Chris Mason , Steven Rostedt , Ingo Molnar , paulmck@linux.vnet.ibm.com, Gregory Haskins , Matthew Wilcox , Andi Kleen , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich Subject: Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning In-Reply-To: <1231442609.27687.1.camel@twins> Message-ID: References: <1231441350.14304.48.camel@think.oraclecorp.com> <1231442609.27687.1.camel@twins> User-Agent: Alpine 1.10 (LRH 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1045 Lines: 26 On Thu, 8 Jan 2009, Peter Zijlstra wrote: > > Well, at least we do unless you enable that broken paravirt support. > > I'm not at all clear on why CONFIG_PARAVIRT wants to use inferior > > locks, but I don't much care. > Because the virtual cpu that has the ticket might not get scheduled for > a while, even though another vcpu with a spinner is scheduled. > The whole (para)virt is a nightmare in that respect. Hmm, are we in fact really using byte locks in CONFIG_PARAVIRT situation? Where are we actually setting pv_lock_ops.spin_lock pointer to point to __byte_spin_lock? Such initialization seems to happen only in paravirt_use_bytelocks() function, but my blind eyes prevent me from finding a callsite from which this function would eventually get called. -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/