From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, 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" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 17/23] rcu: Add random PROVE_RCU_DELAY to grace-period initialization
Date: Thu, 20 Sep 2012 11:48:13 -0700 [thread overview]
Message-ID: <1348166900-18716-17-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1348166900-18716-1-git-send-email-paulmck@linux.vnet.ibm.com>
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Preemption greatly raised the probability of certain types of race
conditions, so this commit adds an anti-heisenbug to greatly increase
the collision cross section, also known as the probability of occurrence.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---
kernel/rcutree.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 25a671c..5cb003d 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -52,6 +52,7 @@
#include <linux/prefetch.h>
#include <linux/delay.h>
#include <linux/stop_machine.h>
+#include <linux/random.h>
#include "rcutree.h"
#include <trace/events/rcu.h>
@@ -1085,6 +1086,10 @@ static int rcu_gp_init(struct rcu_state *rsp)
rnp->level, rnp->grplo,
rnp->grphi, rnp->qsmask);
raw_spin_unlock_irq(&rnp->lock);
+#ifdef CONFIG_PROVE_RCU_DELAY
+ if ((random32() % (rcu_num_nodes * 8)) == 0)
+ schedule_timeout_uninterruptible(2);
+#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
cond_resched();
}
--
1.7.8
next prev parent reply other threads:[~2012-09-20 18:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 18:47 [PATCH tip/core/rcu 0/23] v2 Improvements to RT response on big systems and expedited functions Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 01/23] rcu: Move RCU grace-period initialization into a kthread Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 02/23] rcu: Prevent initialization-time quiescent-state race Paul E. McKenney
2012-09-20 18:47 ` [PATCH tip/core/rcu 03/23] rcu: Allow RCU grace-period initialization to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 04/23] rcu: Move RCU grace-period cleanup into kthread Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 05/23] rcu: Allow RCU grace-period cleanup to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 06/23] rcu: Break up rcu_gp_kthread() into subfunctions Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 07/23] rcu: Prevent offline CPUs from executing RCU core code Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 08/23] rcu: Provide OOM handler to motivate lazy RCU callbacks Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 09/23] rcu: Segregate rcu_state fields to improve cache locality Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 10/23] rcu: Move quiescent-state forcing into kthread Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 11/23] rcu: Allow RCU quiescent-state forcing to be preempted Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 12/23] rcu: Adjust debugfs tracing for kthread-based quiescent-state forcing Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 13/23] rcu: Prevent force_quiescent_state() memory contention Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 14/23] rcu: Control grace-period duration from sysfs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 15/23] rcu: Make rcutree module parameters visible in sysfs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 16/23] rcu: Fix day-zero grace-period initialization/cleanup race Paul E. McKenney
2012-09-20 18:48 ` Paul E. McKenney [this message]
2012-09-20 18:48 ` [PATCH tip/core/rcu 18/23] rcu: Adjust for unconditional ->completed assignment Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 19/23] rcu: Eliminate signed overflow in synchronize_rcu_expedited() Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 20/23] rcu: Reduce synchronize_rcu_expedited() latency Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 21/23] rcu: Simplify quiescent-state detection Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 22/23] rcu: Handle unbalanced rcu_node configurations with few CPUs Paul E. McKenney
2012-09-20 18:48 ` [PATCH tip/core/rcu 23/23] rcu: Shrink RCU based on number of CPUs Paul E. McKenney
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