From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755052AbYCVUtk (ORCPT ); Sat, 22 Mar 2008 16:49:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752766AbYCVUtc (ORCPT ); Sat, 22 Mar 2008 16:49:32 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:50939 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752729AbYCVUtb (ORCPT ); Sat, 22 Mar 2008 16:49:31 -0400 Date: Sat, 22 Mar 2008 13:46:56 -0700 From: Arjan van de Ven To: Jeremy Fitzhardinge Cc: Peter Zijlstra , Ingo Molnar , Linux Kernel Mailing List Subject: Re: How to avoid spurious lockdep warnings? Message-ID: <20080322134656.173de045@laptopd505.fenrus.org> In-Reply-To: <47E2ECF3.2050606@goop.org> References: <47E2ECF3.2050606@goop.org> Organization: Intel X-Mailer: Claws Mail 3.2.0 (GTK+ 2.12.5; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 Mar 2008 16:02:11 -0700 Jeremy Fitzhardinge wrote: > In a Xen system, when a new pagetable is about to be put in use it is > "pinned", meaning that each page in the pagetable is registered with > the hypervisor. This is done in arch/x86/xen/mmu.c:pin_page(). > > In order to make this efficient, the hypercalls for pinning are > batched, so that multiple pages are submitted at once in a single > multicall. While a page is batched pending the hypercall, its > corresponding pte_lock is held. > > This means that the code can end up holding multiple pte locks at > once, though it is guaranteed to never try to hold the same lock at > once. However, because these locks are in the same lock class, I get > a spurious warning from lockdep. Is there some way I can get rid of > this warning? what's the ordering guarantee between these locks ? -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org