From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751969AbaEOXs4 (ORCPT ); Thu, 15 May 2014 19:48:56 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:44240 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750927AbaEOXsz (ORCPT ); Thu, 15 May 2014 19:48:55 -0400 Date: Thu, 15 May 2014 16:48:50 -0700 From: "Paul E. McKenney" To: Andrew Morton Cc: riel@redhat.com, linux-kernel@vger.kernel.org, rdunlap@infradead.org, richard@nod.at, umgwanakikbuti@gmail.com Subject: Re: [PATCH 2/2] sysrq,rcu: suppress RCU stall warnings while sysrq runs Message-ID: <20140515234850.GS4570@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1398794796-17464-1-git-send-email-riel@redhat.com> <1398794796-17464-3-git-send-email-riel@redhat.com> <20140515162412.51355f308c34768ad08c0e2f@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140515162412.51355f308c34768ad08c0e2f@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14051523-1344-0000-0000-00000194BAE9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 15, 2014 at 04:24:12PM -0700, Andrew Morton wrote: > On Tue, 29 Apr 2014 14:06:36 -0400 riel@redhat.com wrote: > > > From: Rik van Riel > > > > Some sysrq handlers can run for a long time, because they dump a lot > > of data onto a serial console. Having RCU stall warnings pop up in > > the middle of them only makes the problem worse. > > > > This patch temporarily disables RCU stall warnings while a sysrq > > request is handled. > > > > ... > > > > drivers/tty/sysrq.c | 3 +++ > > include/linux/rcupdate.h | 12 ++++++++++++ > > kernel/rcu/update.c | 12 ++++++++++++ > > OK, what's going on here. Someone (of, I suspect, a Paulish nature) > has plucked out the rcu parts of this patch, put them in linux-next and > omitted the drivers/tty part. Very tricky! Sounds like something I might do... ;-) I intend to push this for the upcoming merge window, in case it matters. > I have done the opposite and have staged two patches against linux-next: > > http://ozlabs.org/~akpm/mmots/broken-out/sysrq-rcu-ify-__handle_sysrq.patch I defer to Rik for this one. > http://ozlabs.org/~akpm/mmots/broken-out/sysrqrcu-suppress-rcu-stall-warnings-while-sysrq-runs.patch The "[paulmck@linux.vnet.ibm.com: fix TINY_RCU build error]" should be removed, since it goes with the patch I queued. Not that it matters that much, I suppose. Thanx, Paul > Please check, review, comment, etc. >