From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759281Ab3D3HLr (ORCPT ); Tue, 30 Apr 2013 03:11:47 -0400 Received: from ja.ssi.bg ([178.16.129.10]:38848 "EHLO ja.ssi.bg" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1759217Ab3D3HLo (ORCPT ); Tue, 30 Apr 2013 03:11:44 -0400 Date: Tue, 30 Apr 2013 10:12:38 +0300 (EEST) From: Julian Anastasov To: Simon Horman cc: Eric Dumazet , Ingo Molnar , Peter Zijlstra , "Paul E. McKenney" , lvs-devel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Pablo Neira Ayuso , Dipankar Sarma Subject: Re: [PATCH v2 1/2] sched: Add cond_resched_rcu_lock() helper In-Reply-To: <1367290378-29224-2-git-send-email-horms@verge.net.au> Message-ID: References: <1367290378-29224-1-git-send-email-horms@verge.net.au> <1367290378-29224-2-git-send-email-horms@verge.net.au> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, 30 Apr 2013, Simon Horman wrote: > This is intended for use in loops which read data protected by RCU and may > have a large number of iterations. Such an example is dumping the list of > connections known to IPVS: ip_vs_conn_array() and ip_vs_conn_seq_next(). > > The call to cond_resched() is guarded by #ifndef CONFIG_PREEMPT_RCU as in > the case of CONFIG_PREEMPT_RCU _rcu_read_unlock() will check to see if the > RCU core needs to be informed, so there is no need to invoke cond_resched() > in that case. Thanks to Paul E. McKenney for explaining this. > > cond_resched_rcu_lock() suggested by Eric Dumazet. > ifndef guard suggested by Paul E. McKenney and Julian Anastasov. > > Cc: Eric Dumazet > Cc: Paul E. McKenney > Cc: Julian Anastasov > Acked-by: Ingo Molnar > Signed-off-by: Simon Horman > > --- > > v2 > * Add guard the call to cond_resched() > --- > include/linux/sched.h | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index e692a02..66da71c 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -2787,3 +2787,14 @@ static inline unsigned long rlimit_max(unsigned int limit) > } > > #endif > + > +static void inline cond_resched_rcu_lock(void) > +{ > + if (need_resched()) { Ops, it should be without above need_resched. > + rcu_read_unlock(); > +#ifndef CONFIG_PREEMPT_RCU > + cond_resched(); > +#endif > + rcu_read_lock(); > + } > +} > -- > 1.8.2.1 Regards -- Julian Anastasov