Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754004Ab3IINut (ORCPT ); Mon, 9 Sep 2013 09:50:49 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:39354 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752450Ab3IINur (ORCPT ); Mon, 9 Sep 2013 09:50:47 -0400 Date: Mon, 9 Sep 2013 06:50:38 -0700 From: "Paul E. McKenney" To: Steven Rostedt Cc: Frederic Weisbecker , Peter Zijlstra , Eric Dumazet , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, sbw@mit.edu Subject: Re: [PATCH] rcu: Is it safe to enter an RCU read-side critical section? Message-ID: <20130909135038.GR3966@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130906174117.GU3966@linux.vnet.ibm.com> <20130906185927.GE2706@somewhere> <20130909105347.GK31370@twins.programming.kicks-ass.net> <20130909121329.GA16280@somewhere> <20130909083926.3eceebef@gandalf.local.home> <20130909124547.GB16280@somewhere> <20130909085504.2ddd7e69@gandalf.local.home> <20130909131452.GA31370@twins.programming.kicks-ass.net> <20130909132900.GE16280@somewhere> <20130909094132.74f1dd57@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130909094132.74f1dd57@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13090913-0320-0000-0000-000000EF1127 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 839 Lines: 23 On Mon, Sep 09, 2013 at 09:41:32AM -0400, Steven Rostedt wrote: > On Mon, 9 Sep 2013 15:29:02 +0200 > Frederic Weisbecker wrote: > > > > No, putting that on the task_struct won't help much in this regard I think. > > Regular schedule() calls don't change that per cpu state. > > But is there a place that it would need to? > > I mean, if RCU is not tracking a CPU, is it safe to call schedule(). > And then how would the new task know that RCU is ignoring that CPU? Guys, RCU really is tracking per-CPU state with the rcu_dynticks.dynticks field. Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/