From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932178AbXCHR3P (ORCPT ); Thu, 8 Mar 2007 12:29:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932186AbXCHR3P (ORCPT ); Thu, 8 Mar 2007 12:29:15 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:59169 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932173AbXCHR3M (ORCPT ); Thu, 8 Mar 2007 12:29:12 -0500 Date: Thu, 8 Mar 2007 18:29:02 +0100 From: Ingo Molnar To: Nick Piggin Cc: Linux Kernel Mailing List , Thomas Gleixner Subject: Re: [rfc][patch] futex: restartable futex_wait? Message-ID: <20070308172902.GA16834@elte.hu> References: <20070307153349.GA32404@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070307153349.GA32404@wotan.suse.de> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Nick Piggin wrote: > Hi Ingo, > > I'm seeing an LTP test fail for ltp test sigaction_16_24. Basically, > it tests whether the SA_RESTART flag works for the sem_wait operation. > > I see sem_wait is implemented with futex_wait, so I wonder whether we > can make it restartable? Am I going about it the right way? (Seems to > fix the testcase here). i think that's quite right. I'm wondering why this never came up before? But your fix is not complete i think: > + restart->arg2 = time; > + return -ERESTART_RESTARTBLOCK; > + } 'time' here is relative, so the restarted syscall will do a /full/ wait again. maybe we should rather convert futex timed-waits to hrtimers? Thomas? Ingo