[tip:core/urgent] rcu: Increase RCU CPU stall timeouts if PROVE_RCU

["tip-bot for Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

Commit-ID:  007b09243b099811124f69d492adeebe9e439f96
Gitweb:     http://git.kernel.org/tip/007b09243b099811124f69d492adeebe9e439f96
Author:     Paul E. McKenney <paulmck@linux.vnet.ibm.com>
AuthorDate: Fri, 5 Mar 2010 15:03:26 -0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 11 Mar 2010 13:38:01 +0100

rcu: Increase RCU CPU stall timeouts if PROVE_RCU

CONFIG_PROVE_RCU imposes additional overhead on the kernel, so
increase the RCU CPU stall timeouts in an attempt to allow for
this effect.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267830207-9474-2-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/rcutree.h |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 1439eb5..4a525a3 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -246,12 +246,21 @@ struct rcu_data {
 
 #define RCU_JIFFIES_TILL_FORCE_QS	 3	/* for rsp->jiffies_force_qs */
 #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
-#define RCU_SECONDS_TILL_STALL_CHECK   (10 * HZ)  /* for rsp->jiffies_stall */
-#define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ)  /* for rsp->jiffies_stall */
-#define RCU_STALL_RAT_DELAY		2	  /* Allow other CPUs time */
-						  /*  to take at least one */
-						  /*  scheduling clock irq */
-						  /*  before ratting on them. */
+
+#ifdef CONFIG_PROVE_RCU
+#define RCU_STALL_DELAY_DELTA	       (5 * HZ)
+#else
+#define RCU_STALL_DELAY_DELTA	       0
+#endif
+
+#define RCU_SECONDS_TILL_STALL_CHECK   (10 * HZ + RCU_STALL_DELAY_DELTA)
+						/* for rsp->jiffies_stall */
+#define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ + RCU_STALL_DELAY_DELTA)
+						/* for rsp->jiffies_stall */
+#define RCU_STALL_RAT_DELAY		2	/* Allow other CPUs time */
+						/*  to take at least one */
+						/*  scheduling clock irq */
+						/*  before ratting on them. */
 
 #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */