From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753841Ab3BACPh (ORCPT ); Thu, 31 Jan 2013 21:15:37 -0500 Received: from mga09.intel.com ([134.134.136.24]:45070 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570Ab3BACPf (ORCPT ); Thu, 31 Jan 2013 21:15:35 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,579,1355126400"; d="scan'208";a="255858643" Date: Fri, 1 Feb 2013 10:16:28 +0800 From: Yuanhan Liu To: Ingo Molnar Cc: Michel Lespinasse , linux-kernel@vger.kernel.org, David Howells Subject: Re: [PATCH] rwsem-spinlock: let rwsem write lock stealable Message-ID: <20130201021628.GC12678@yliu-dev.sh.intel.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> <20130131211818.GA13195@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130131211818.GA13195@gmail.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 On Thu, Jan 31, 2013 at 10:18:18PM +0100, Ingo Molnar wrote: > > * 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. Good to know. > > > 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. Reall sorry about that. My bad. I modify the code a bit: removed the two //, so that thread will exit after count > 1000000. Sorry again :( --yliu > 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. > > Thanks, > > Ingo