Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754181Ab2K2PGs (ORCPT ); Thu, 29 Nov 2012 10:06:48 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:51431 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750931Ab2K2PGq (ORCPT ); Thu, 29 Nov 2012 10:06:46 -0500 Date: Thu, 29 Nov 2012 03:36:27 -0800 From: "Paul E. McKenney" To: Frederic Weisbecker Cc: Li Zhong , LKML , Andrew Morton , "H. Peter Anvin" , Ingo Molnar , Peter Zijlstra , Steven Rostedt , Thomas Gleixner , Gilad.Ben-Yossef.gilad@benyossef.com Subject: Re: [PATCH] context_tracking: New context tracking susbsystem Message-ID: <20121129113627.GS2474@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1354041205-6989-1-git-send-email-fweisbec@gmail.com> <1354179992.2499.35.camel@ThinkPad-T5421.cn.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12112915-5406-0000-0000-000002863769 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2574 Lines: 66 On Thu, Nov 29, 2012 at 11:30:19AM +0100, Frederic Weisbecker wrote: > 2012/11/29 Li Zhong : > > On Tue, 2012-11-27 at 19:33 +0100, Frederic Weisbecker wrote: > > [....] > >> - > >> - WARN_ON_ONCE(!current->mm); > >> - > >> - local_irq_save(flags); > >> - rdtp = &__get_cpu_var(rcu_dynticks); > >> - if (!rdtp->ignore_user_qs && !rdtp->in_user) { > >> - rdtp->in_user = true; > >> - rcu_eqs_enter(true); > >> - } > > > > It seems to me that ignore_user_qs and in_user defined in struct > > rcu_dynticks are no longer needed? > > > > If so, then maybe we could remove them, code below: > > > > ========== > > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > > index e441b77..b8fae5d 100644 > > --- a/kernel/rcutree.c > > +++ b/kernel/rcutree.c > > @@ -2719,9 +2719,6 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) > > rdp->dynticks = &per_cpu(rcu_dynticks, cpu); > > WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != DYNTICK_TASK_EXIT_IDLE); > > WARN_ON_ONCE(atomic_read(&rdp->dynticks->dynticks) != 1); > > -#ifdef CONFIG_RCU_USER_QS > > - WARN_ON_ONCE(rdp->dynticks->in_user); > > -#endif > > rdp->cpu = cpu; > > rdp->rsp = rsp; > > rcu_boot_init_nocb_percpu_data(rdp); > > diff --git a/kernel/rcutree.h b/kernel/rcutree.h > > index 4b69291..6f21f2e 100644 > > --- a/kernel/rcutree.h > > +++ b/kernel/rcutree.h > > @@ -102,10 +102,6 @@ struct rcu_dynticks { > > /* idle-period nonlazy_posted snapshot. */ > > int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */ > > #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */ > > -#ifdef CONFIG_RCU_USER_QS > > - bool ignore_user_qs; /* Treat userspace as extended QS or not */ > > - bool in_user; /* Is the CPU in userland from RCU POV? */ > > -#endif > > }; > > > > /* RCU's kthread states for tracing. */ > > > > > > Good point. Paul, do you prefer to fold these changes into my patch or > do we add a new one? In any case Li we need your Signed-off-by tag. A separate patch works fine here because there should be no complaints from compilers or tests about these. Zhong, please do send with your Signed-off-by, and I will queue them. 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/