From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752126AbbGBDPl (ORCPT ); Wed, 1 Jul 2015 23:15:41 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:55895 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751051AbbGBDPf (ORCPT ); Wed, 1 Jul 2015 23:15:35 -0400 X-Helo: d03dlp01.boulder.ibm.com X-MailFrom: paulmck@linux.vnet.ibm.com X-RcptTo: linux-kernel@vger.kernel.org Date: Wed, 1 Jul 2015 20:15:29 -0700 From: "Paul E. McKenney" To: Mike Galbraith Cc: josh@joshtriplett.org, Peter Zijlstra , linux-kernel@vger.kernel.org, mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, tglx@linutronix.de, 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 RFC tip/core/rcu 0/5] Expedited grace periods encouraging normal ones Message-ID: <20150702031529.GB3717@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20150701100939.GR19282@twins.programming.kicks-ass.net> <20150701105511.GN18673@twins.programming.kicks-ass.net> <20150701140031.GB3717@linux.vnet.ibm.com> <20150701141710.GG25159@twins.programming.kicks-ass.net> <20150701161705.GK3717@linux.vnet.ibm.com> <1435799484.3482.15.camel@gmail.com> <20150702013426.GB19350@cloud> <1435802395.6887.20.camel@gmail.com> <20150702021838.GA3717@linux.vnet.ibm.com> <1435805445.6887.50.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1435805445.6887.50.camel@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15070203-0021-0000-0000-00000E0C20EE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 02, 2015 at 04:50:45AM +0200, Mike Galbraith wrote: > On Wed, 2015-07-01 at 19:18 -0700, Paul E. McKenney wrote: > > > Does their normal workload trigger the condition that results in the > > expedited grace period? If so, do they use NO_HZ_FULL? > > They're having no trouble that I'm aware of, and I definitely would be > made aware. They're not currently using a kernel with NO_HZ_FULL even > built in, as that stuff is far far too raw in the current kernel. > > They may meet a NO_HZ_FULL enabled kernel soonish, but will be told to > not turn it on for anything other than pure compute, as NO_HZ_FULL is > currently not usable for mixed load in partitioned box, much less rt. OK, sounds like synchronize_rcu_expedited() is a complete non-problem for them, then. Thanx, Paul