From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751022AbdAPIJc (ORCPT ); Mon, 16 Jan 2017 03:09:32 -0500 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:38336 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750863AbdAPIIx (ORCPT ); Mon, 16 Jan 2017 03:08:53 -0500 X-Originating-IP: 50.39.169.170 Date: Mon, 16 Jan 2017 00:08:43 -0800 From: Josh Triplett To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, 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 11/20] sched,rcu: Make cond_resched() provide RCU quiescent state Message-ID: <20170116080842.3hj3j4632vgec63f@x> References: <20170114091255.GA20854@linux.vnet.ibm.com> <1484385201-22227-11-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1484385201-22227-11-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: NeoMutt/20161126 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 14, 2017 at 01:13:12AM -0800, Paul E. McKenney wrote: > There is some confusion as to which of cond_resched() or > cond_resched_rcu_qs() should be added to long in-kernel loops. > This commit therefore eliminates the decision by adding RCU > quiescent states to cond_resched(). > > Warning: This is a prototype. For example, it does not correctly > handle Tasks RCU. Which is OK for the moment, given that no one > actually uses Tasks RCU yet. > > Reported-by: Michal Hocko > Not-yet-signed-off-by: Paul E. McKenney > Cc: Peter Zijlstra Do you intend to merge this patch, or have you just posted it for review? You may want to remove it from this 20-patch series and post it as a separate RFC PATCH, to ensure that it doesn't get merged while still a prototype. > include/linux/sched.h | 3 ++- > kernel/sched/core.c | 1 + > 2 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 4d1905245c7a..1531c48f56e2 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -3352,10 +3352,11 @@ static inline int signal_pending_state(long state, struct task_struct *p) > * cond_resched_lock() will drop the spinlock before scheduling, > * cond_resched_softirq() will enable bhs before scheduling. > */ > +void rcu_all_qs(void); > #ifndef CONFIG_PREEMPT > extern int _cond_resched(void); > #else > -static inline int _cond_resched(void) { return 0; } > +static inline int _cond_resched(void) { rcu_all_qs(); return 0; } > #endif > > #define cond_resched() ({ \ > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index c56fb57f2991..b442f8918eb9 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4907,6 +4907,7 @@ int __sched _cond_resched(void) > preempt_schedule_common(); > return 1; > } > + rcu_all_qs(); > return 0; > } > EXPORT_SYMBOL(_cond_resched); > -- > 2.5.2 >