Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760297Ab3D3Cp5 (ORCPT ); Mon, 29 Apr 2013 22:45:57 -0400 Received: from kirsty.vergenet.net ([202.4.237.240]:36038 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758206Ab3D3Cpz (ORCPT ); Mon, 29 Apr 2013 22:45:55 -0400 Date: Tue, 30 Apr 2013 11:45:52 +0900 From: Simon Horman To: Ingo Molnar Cc: Eric Dumazet , Julian Anastasov , Ingo Molnar , Peter Zijlstra , lvs-devel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Pablo Neira Ayuso , Dipankar Sarma , "Paul E. McKenney" Subject: Re: [PATCH 2/2] ipvs: Use cond_resched_rcu_lock() helper when dumping connections Message-ID: <20130430024552.GA26726@verge.net.au> References: <1366940708-10180-1-git-send-email-horms@verge.net.au> <1366940708-10180-3-git-send-email-horms@verge.net.au> <20130426061534.GB25912@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130426061534.GB25912@gmail.com> Organisation: Horms Solutions Ltd. User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1950 Lines: 52 On Fri, Apr 26, 2013 at 08:15:34AM +0200, Ingo Molnar wrote: > > * Simon Horman wrote: > > > This avoids the situation where a dump of a large number of connections > > may prevent scheduling for a long time while also avoiding excessive > > calls to rcu_read_unlock() and rcu_read_lock(). > > > > Cc: Eric Dumazet > > Cc: Julian Anastasov > > Signed-off-by: Simon Horman > > --- > > net/netfilter/ipvs/ip_vs_conn.c | 6 ++---- > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c > > index a083bda..42a7b33 100644 > > --- a/net/netfilter/ipvs/ip_vs_conn.c > > +++ b/net/netfilter/ipvs/ip_vs_conn.c > > @@ -975,8 +975,7 @@ static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos) > > return cp; > > } > > } > > - rcu_read_unlock(); > > - rcu_read_lock(); > > + cond_resched_rcu_lock(); > > } > > > > return NULL; > > @@ -1015,8 +1014,7 @@ static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos) > > iter->l = &ip_vs_conn_tab[idx]; > > return cp; > > } > > - rcu_read_unlock(); > > - rcu_read_lock(); > > + cond_resched_rcu_lock(); > > Feel free to route this via the networking tree. > > Note that this change isn't a pure clean-up but has functional effects as > well: on !PREEMPT or PREEMPT_VOLUNTARY kernels it will add in a potential > cond_resched() - while previously it would only rcu unlock and relock > (which in itself isn't scheduling). > > This should probably be pointed out in the changelog. Thanks, I have added some text which I will include in v2. -- 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/