Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754432Ab3DZGPk (ORCPT ); Fri, 26 Apr 2013 02:15:40 -0400 Received: from mail-ea0-f174.google.com ([209.85.215.174]:37233 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752292Ab3DZGPi (ORCPT ); Fri, 26 Apr 2013 02:15:38 -0400 Date: Fri, 26 Apr 2013 08:15:34 +0200 From: Ingo Molnar To: Simon Horman 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: <20130426061534.GB25912@gmail.com> References: <1366940708-10180-1-git-send-email-horms@verge.net.au> <1366940708-10180-3-git-send-email-horms@verge.net.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1366940708-10180-3-git-send-email-horms@verge.net.au> 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: 1757 Lines: 53 * 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, Ingo -- 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/