From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754104Ab2IBGGG (ORCPT ); Sun, 2 Sep 2012 02:06:06 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:50240 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752138Ab2IBGGD (ORCPT ); Sun, 2 Sep 2012 02:06:03 -0400 X-Originating-IP: 217.70.178.150 X-Originating-IP: 50.43.46.74 Date: Sat, 1 Sep 2012 23:05:54 -0700 From: Josh Triplett To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org Subject: Re: [PATCH tip/core/rcu 11/23] rcu: Adjust debugfs tracing for kthread-based quiescent-state forcing Message-ID: <20120902060554.GC7767@leaf> References: <20120830181811.GA29154@linux.vnet.ibm.com> <1346350718-30937-1-git-send-email-paulmck@linux.vnet.ibm.com> <1346350718-30937-11-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: <1346350718-30937-11-git-send-email-paulmck@linux.vnet.ibm.com> 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 On Thu, Aug 30, 2012 at 11:18:26AM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" > > Moving quiescent-state forcing into a kthread dispenses with the need > for the ->n_rp_need_fqs field, so this commit removes it. > > Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett > Documentation/RCU/trace.txt | 43 ++++++++++++++++--------------------------- > kernel/rcutree.h | 1 - > kernel/rcutree_trace.c | 3 +-- > 3 files changed, 17 insertions(+), 30 deletions(-) > > diff --git a/Documentation/RCU/trace.txt b/Documentation/RCU/trace.txt > index f6f15ce..672d190 100644 > --- a/Documentation/RCU/trace.txt > +++ b/Documentation/RCU/trace.txt > @@ -333,23 +333,23 @@ o Each element of the form "1/1 0:127 ^0" represents one struct > The output of "cat rcu/rcu_pending" looks as follows: > > rcu_sched: > - 0 np=255892 qsp=53936 rpq=85 cbr=0 cng=14417 gpc=10033 gps=24320 nf=6445 nn=146741 > - 1 np=261224 qsp=54638 rpq=33 cbr=0 cng=25723 gpc=16310 gps=2849 nf=5912 nn=155792 > - 2 np=237496 qsp=49664 rpq=23 cbr=0 cng=2762 gpc=45478 gps=1762 nf=1201 nn=136629 > - 3 np=236249 qsp=48766 rpq=98 cbr=0 cng=286 gpc=48049 gps=1218 nf=207 nn=137723 > - 4 np=221310 qsp=46850 rpq=7 cbr=0 cng=26 gpc=43161 gps=4634 nf=3529 nn=123110 > - 5 np=237332 qsp=48449 rpq=9 cbr=0 cng=54 gpc=47920 gps=3252 nf=201 nn=137456 > - 6 np=219995 qsp=46718 rpq=12 cbr=0 cng=50 gpc=42098 gps=6093 nf=4202 nn=120834 > - 7 np=249893 qsp=49390 rpq=42 cbr=0 cng=72 gpc=38400 gps=17102 nf=41 nn=144888 > + 0 np=255892 qsp=53936 rpq=85 cbr=0 cng=14417 gpc=10033 gps=24320 nn=146741 > + 1 np=261224 qsp=54638 rpq=33 cbr=0 cng=25723 gpc=16310 gps=2849 nn=155792 > + 2 np=237496 qsp=49664 rpq=23 cbr=0 cng=2762 gpc=45478 gps=1762 nn=136629 > + 3 np=236249 qsp=48766 rpq=98 cbr=0 cng=286 gpc=48049 gps=1218 nn=137723 > + 4 np=221310 qsp=46850 rpq=7 cbr=0 cng=26 gpc=43161 gps=4634 nn=123110 > + 5 np=237332 qsp=48449 rpq=9 cbr=0 cng=54 gpc=47920 gps=3252 nn=137456 > + 6 np=219995 qsp=46718 rpq=12 cbr=0 cng=50 gpc=42098 gps=6093 nn=120834 > + 7 np=249893 qsp=49390 rpq=42 cbr=0 cng=72 gpc=38400 gps=17102 nn=144888 > rcu_bh: > - 0 np=146741 qsp=1419 rpq=6 cbr=0 cng=6 gpc=0 gps=0 nf=2 nn=145314 > - 1 np=155792 qsp=12597 rpq=3 cbr=0 cng=0 gpc=4 gps=8 nf=3 nn=143180 > - 2 np=136629 qsp=18680 rpq=1 cbr=0 cng=0 gpc=7 gps=6 nf=0 nn=117936 > - 3 np=137723 qsp=2843 rpq=0 cbr=0 cng=0 gpc=10 gps=7 nf=0 nn=134863 > - 4 np=123110 qsp=12433 rpq=0 cbr=0 cng=0 gpc=4 gps=2 nf=0 nn=110671 > - 5 np=137456 qsp=4210 rpq=1 cbr=0 cng=0 gpc=6 gps=5 nf=0 nn=133235 > - 6 np=120834 qsp=9902 rpq=2 cbr=0 cng=0 gpc=6 gps=3 nf=2 nn=110921 > - 7 np=144888 qsp=26336 rpq=0 cbr=0 cng=0 gpc=8 gps=2 nf=0 nn=118542 > + 0 np=146741 qsp=1419 rpq=6 cbr=0 cng=6 gpc=0 gps=0 nn=145314 > + 1 np=155792 qsp=12597 rpq=3 cbr=0 cng=0 gpc=4 gps=8 nn=143180 > + 2 np=136629 qsp=18680 rpq=1 cbr=0 cng=0 gpc=7 gps=6 nn=117936 > + 3 np=137723 qsp=2843 rpq=0 cbr=0 cng=0 gpc=10 gps=7 nn=134863 > + 4 np=123110 qsp=12433 rpq=0 cbr=0 cng=0 gpc=4 gps=2 nn=110671 > + 5 np=137456 qsp=4210 rpq=1 cbr=0 cng=0 gpc=6 gps=5 nn=133235 > + 6 np=120834 qsp=9902 rpq=2 cbr=0 cng=0 gpc=6 gps=3 nn=110921 > + 7 np=144888 qsp=26336 rpq=0 cbr=0 cng=0 gpc=8 gps=2 nn=118542 > > As always, this is once again split into "rcu_sched" and "rcu_bh" > portions, with CONFIG_TREE_PREEMPT_RCU kernels having an additional > @@ -377,17 +377,6 @@ o "gpc" is the number of times that an old grace period had > o "gps" is the number of times that a new grace period had started, > but this CPU was not yet aware of it. > > -o "nf" is the number of times that this CPU suspected that the > - current grace period had run for too long, and thus needed to > - be forced. > - > - Please note that "forcing" consists of sending resched IPIs > - to holdout CPUs. If that CPU really still is in an old RCU > - read-side critical section, then we really do have to wait for it. > - The assumption behing "forcing" is that the CPU is not still in > - an old RCU read-side critical section, but has not yet responded > - for some other reason. > - > o "nn" is the number of times that this CPU needed nothing. Alert > readers will note that the rcu "nn" number for a given CPU very > closely matches the rcu_bh "np" number for that same CPU. This > diff --git a/kernel/rcutree.h b/kernel/rcutree.h > index 1f26b1f..36916df 100644 > --- a/kernel/rcutree.h > +++ b/kernel/rcutree.h > @@ -312,7 +312,6 @@ struct rcu_data { > unsigned long n_rp_cpu_needs_gp; > unsigned long n_rp_gp_completed; > unsigned long n_rp_gp_started; > - unsigned long n_rp_need_fqs; > unsigned long n_rp_need_nothing; > > /* 6) _rcu_barrier() and OOM callbacks. */ > diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c > index abffb48..f54f0ce 100644 > --- a/kernel/rcutree_trace.c > +++ b/kernel/rcutree_trace.c > @@ -386,10 +386,9 @@ static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp) > rdp->n_rp_report_qs, > rdp->n_rp_cb_ready, > rdp->n_rp_cpu_needs_gp); > - seq_printf(m, "gpc=%ld gps=%ld nf=%ld nn=%ld\n", > + seq_printf(m, "gpc=%ld gps=%ld nn=%ld\n", > rdp->n_rp_gp_completed, > rdp->n_rp_gp_started, > - rdp->n_rp_need_fqs, > rdp->n_rp_need_nothing); > } > > -- > 1.7.8 >