From: Josh Triplett <josh@joshtriplett.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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,
"Paul E. McKenney" <paul.mckenney@linaro.org>
Subject: Re: [PATCH tip/core/rcu 11/15] rcu: Avoid spurious RCU CPU stall warnings
Date: Fri, 31 Aug 2012 11:24:29 -0700 [thread overview]
Message-ID: <20120831182429.GI4259@jtriplet-mobl1> (raw)
In-Reply-To: <1346352988-32444-11-git-send-email-paulmck@linux.vnet.ibm.com>
On Thu, Aug 30, 2012 at 11:56:24AM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paul.mckenney@linaro.org>
>
> If a given CPU avoids the idle loop but also avoids starting a new
> RCU grace period for a full minute, RCU can issue spurious RCU CPU
> stall warnings. This commit fixes this issue by adding a check for
> ongoing grace period to avoid these spurious stall warnings.
>
> Reported-by: Becky Bruce <bgillbruce@gmail.com>
> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
> ---
> kernel/rcutree.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/rcutree.c b/kernel/rcutree.c
> index fbe43b0..e58097b 100644
> --- a/kernel/rcutree.c
> +++ b/kernel/rcutree.c
> @@ -820,7 +820,8 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
> j = ACCESS_ONCE(jiffies);
> js = ACCESS_ONCE(rsp->jiffies_stall);
> rnp = rdp->mynode;
> - if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {
> + if (rcu_gp_in_progress(rsp) &&
> + (ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {
>
> /* We haven't checked in, so go dump stack. */
> print_cpu_stall(rsp);
> --
> 1.7.8
>
next prev parent reply other threads:[~2012-08-31 18:24 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-30 18:56 [PATCH tip/core/rcu 0/15] Miscellaneous fixes Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 01/15] rcu: Add PROVE_RCU_DELAY to provoke difficult races Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 02/15] rcu: Pull TINY_RCU dyntick-idle tracing into non-idle region Paul E. McKenney
2012-08-31 16:53 ` Josh Triplett
2012-08-30 18:56 ` [PATCH tip/core/rcu 03/15] rcu: Properly initialize ->boost_tasks on CPU offline Paul E. McKenney
2012-08-31 17:56 ` Josh Triplett
2012-09-06 14:40 ` Peter Zijlstra
2012-09-06 20:58 ` Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 04/15] rcu: Permit RCU_NONIDLE() to be used from interrupt context Paul E. McKenney
2012-08-31 18:00 ` Josh Triplett
2012-09-04 22:33 ` Paul E. McKenney
2012-09-04 22:48 ` Josh Triplett
2012-09-04 22:51 ` Steven Rostedt
2012-09-04 23:08 ` Josh Triplett
2012-09-04 23:23 ` Steven Rostedt
2012-09-04 23:33 ` Josh Triplett
2012-09-04 23:43 ` Paul E. McKenney
2012-09-06 18:54 ` Josh Triplett
2012-09-06 19:54 ` Steven Rostedt
2012-09-07 6:09 ` Josh Triplett
2012-09-07 14:24 ` Paul E. McKenney
2012-09-07 14:47 ` Josh Triplett
2012-09-07 15:16 ` Steven Rostedt
2012-09-12 1:07 ` Paul E. McKenney
2012-09-12 14:13 ` Steven Rostedt
2012-09-12 15:03 ` Paul E. McKenney
2012-09-12 15:18 ` Steven Rostedt
2012-09-12 16:57 ` Paul E. McKenney
2012-09-04 23:46 ` Steven Rostedt
2012-09-05 0:42 ` Josh Triplett
2012-09-05 6:23 ` [PATCH] trace: Don't declare trace_*_rcuidle functions in modules Josh Triplett
2012-09-05 14:26 ` Mathieu Desnoyers
2012-09-05 16:36 ` Paul E. McKenney
2012-09-06 19:49 ` Steven Rostedt
2012-09-14 6:07 ` [tip:core/rcu] trace: Don' t " tip-bot for Josh Triplett
2012-09-04 23:14 ` [PATCH tip/core/rcu 04/15] rcu: Permit RCU_NONIDLE() to be used from interrupt context Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 05/15] rcu: Improve boost selection when moving tasks to root rcu_node Paul E. McKenney
2012-08-31 18:09 ` Josh Triplett
2012-08-30 18:56 ` [PATCH tip/core/rcu 06/15] rcu: Make offline-CPU checking allow for indefinite delays Paul E. McKenney
2012-08-31 18:12 ` Josh Triplett
2012-08-30 18:56 ` [PATCH tip/core/rcu 07/15] rcu: Fix obsolete rcu_initiate_boost() header comment Paul E. McKenney
2012-08-31 18:13 ` Josh Triplett
2012-08-30 18:56 ` [PATCH tip/core/rcu 08/15] rcu: Apply for_each_rcu_flavor() to increment_cpu_stall_ticks() Paul E. McKenney
2012-08-31 18:15 ` Josh Triplett
2012-09-04 22:44 ` Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 09/15] rcu: Avoid rcu_print_detail_task_stall_rnp() segfault Paul E. McKenney
2012-08-31 18:19 ` Josh Triplett
2012-09-04 22:46 ` Paul E. McKenney
2012-09-04 22:55 ` Josh Triplett
2012-08-30 18:56 ` [PATCH tip/core/rcu 10/15] rcu: Protect rcu_node accesses during CPU stall warnings Paul E. McKenney
2012-08-31 18:23 ` Josh Triplett
2012-09-04 22:51 ` Paul E. McKenney
2012-09-06 14:51 ` Peter Zijlstra
2012-09-06 21:01 ` Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 11/15] rcu: Avoid spurious RCU " Paul E. McKenney
2012-08-31 18:24 ` Josh Triplett [this message]
2012-09-06 14:56 ` Peter Zijlstra
2012-09-06 15:07 ` Steven Rostedt
2012-09-06 15:19 ` Peter Zijlstra
2012-09-06 21:03 ` Paul E. McKenney
2012-09-06 21:41 ` Steven Rostedt
2012-09-06 21:58 ` Paul E. McKenney
2012-09-06 22:05 ` Steven Rostedt
2012-09-06 22:22 ` Paul E. McKenney
2012-09-07 7:00 ` Peter Zijlstra
2012-09-07 14:42 ` Steven Rostedt
2012-08-30 18:56 ` [PATCH tip/core/rcu 12/15] rcu: Remove redundant memory barrier from __call_rcu() Paul E. McKenney
2012-08-31 18:30 ` Josh Triplett
2012-08-31 18:40 ` Josh Triplett
2012-08-30 18:56 ` [PATCH tip/core/rcu 13/15] rcu: Move TINY_PREEMPT_RCU away from raw_local_irq_save() Paul E. McKenney
2012-08-31 18:34 ` Josh Triplett
2012-09-04 23:03 ` Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 14/15] time: RCU permitted to stop idle entry via softirq Paul E. McKenney
2012-08-31 18:51 ` Josh Triplett
2012-09-06 15:12 ` Peter Zijlstra
2012-09-06 21:35 ` Paul E. McKenney
2012-09-06 21:57 ` Steven Rostedt
2012-09-06 22:11 ` Paul E. McKenney
2012-08-30 18:56 ` [PATCH tip/core/rcu 15/15] kmemleak: Replace list_for_each_continue_rcu with new interface Paul E. McKenney
2012-08-31 18:55 ` Josh Triplett
2012-09-04 23:41 ` Paul E. McKenney
2012-08-31 16:49 ` [PATCH tip/core/rcu 01/15] rcu: Add PROVE_RCU_DELAY to provoke difficult races Josh Triplett
2012-09-04 22:36 ` Paul E. McKenney
2012-09-06 14:38 ` Peter Zijlstra
2012-09-06 20:51 ` Paul E. McKenney
2012-09-07 6:54 ` Peter Zijlstra
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