From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758559AbbCDO7t (ORCPT ); Wed, 4 Mar 2015 09:59:49 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:35426 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757758AbbCDO7r (ORCPT ); Wed, 4 Mar 2015 09:59:47 -0500 Date: Wed, 4 Mar 2015 06:59:39 -0800 From: "Paul E. McKenney" To: Paul Bolle Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com Subject: Re: [PATCH tip/core/rcu 10/20] rcu: Provide diagnostic option to slow down grace-period initialization Message-ID: <20150304145939.GK15405@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20150303174144.GA13139@linux.vnet.ibm.com> <1425404595-17816-1-git-send-email-paulmck@linux.vnet.ibm.com> <1425404595-17816-10-git-send-email-paulmck@linux.vnet.ibm.com> <1425466477.2798.5.camel@tiscali.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1425466477.2798.5.camel@tiscali.nl> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15030414-0021-0000-0000-00000901B3AE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 04, 2015 at 11:54:37AM +0100, Paul Bolle wrote: > All I spotted is a silly typo. > > Paul E. McKenney schreef op di 03-03-2015 om 09:43 [-0800]: > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -1257,6 +1257,30 @@ config RCU_TORTURE_TEST_RUNNABLE > > Say N here if you want the RCU torture tests to start only > > after being manually enabled via /proc. > > > > +config RCU_TORTURE_TEST_SLOW_INIT > > + bool "Slow down RCU grace-period initialization to expose races" > > + depends on RCU_TORTURE_TEST > > + help > > + This option makes grace-period initialization block for a > > + few jiffies between initializing each pair of consecutive > > + rcu_node structures. This helps to expose races involving > > + grace-period initialization, in other words, it makes your > > + kernel less stable. It can also greatly increase grace-period > > + latency, especially on systems with large numbers of CPUs. > > + This is useful when torture-testing RCU, but in almost no > > + other circumstance. > > + > > + Say Y here if you want your system to crash and hang more often. > > (Did you ever consider going into marketing?) "Get your cold dead fish here!!! And what is this 'sashimi' you speak of?" But yes, I really do not want distros to enable this one. Unless it is some sort of Ridiculously Unstable Linux distro. ;-) > > + Say N if you want a sane system. > > + > > +config RCU_TORTURE_TEST_SLOW_INIT_DELAY > > + int "How must to slow down RCU grace-period initialization" > > s/must/much/ Good catch, fixed! Thanx, Paul > > + range 0 5 > > + default 0 > > + help > > + This option specifies the number of jiffies to wait between > > + each rcu_node structure initialization. > > + > > config RCU_CPU_STALL_TIMEOUT > > int "RCU CPU stall timeout in seconds" > > depends on RCU_STALL_COMMON > > > Paul Bolle >