From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754435Ab3AaVSZ (ORCPT ); Thu, 31 Jan 2013 16:18:25 -0500 Received: from mail-ea0-f179.google.com ([209.85.215.179]:37252 "EHLO mail-ea0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752424Ab3AaVSX (ORCPT ); Thu, 31 Jan 2013 16:18:23 -0500 Date: Thu, 31 Jan 2013 22:18:18 +0100 From: Ingo Molnar To: Yuanhan Liu Cc: Michel Lespinasse , linux-kernel@vger.kernel.org, David Howells Subject: Re: [PATCH] rwsem-spinlock: let rwsem write lock stealable Message-ID: <20130131211818.GA13195@gmail.com> References: <1359537244-20588-1-git-send-email-yuanhan.liu@linux.intel.com> <20130131124004.GA12678@yliu-dev.sh.intel.com> <20130131131228.GB6627@gmail.com> <20130131143626.GB12678@yliu-dev.sh.intel.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="UlVJffcvxoiEqYs2" Content-Disposition: inline In-Reply-To: <20130131143626.GB12678@yliu-dev.sh.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --UlVJffcvxoiEqYs2 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline * Yuanhan Liu wrote: > On Thu, Jan 31, 2013 at 02:12:28PM +0100, Ingo Molnar wrote: > > > > * Yuanhan Liu wrote: > > > > > BTW, mind to tell a nice test case for mmap_sem? > > > > this one was write-hitting on mmap_sem pretty hard, last I > > checked: > > > > http://people.redhat.com/mingo/threaded-mmap-stresstest/ > > Thanks! > > Is there any pass condition? I tested a while, at least I > found no oops or any noisy from dmesg output. Is that OK? Yeah, not crashing and not hanging is the expected behavior. > Well, sometimes, it will quit peacefully. Sometimes it will > not. ps -eo 'pid, state,wchan,comm' shows that it is sleeping > at futex_wait_queue_me(). > > NOTE: this happens both with or w/o this patch. Thus it may > not an issue introduced by this patch? hm, that's unexpected - it's expected to loop infinitely. I have a newer version (attached) - is that exiting too? Maybe this triggers spuriously: if (!info->si_addr) raise(SIGABRT); /* Allow GDB backtrace */ although then you should see the SIGABRT as an irregular exit IIRC. 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