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From: tip-bot for Paul E. McKenney on 11 Mar 2010 09:40
Commit-ID: 007b09243b099811124f69d492adeebe9e439f96
Gitweb: http://git.kernel.org/tip/007b09243b099811124f69d492adeebe9e439f96
Author: Paul E. McKenney <paulmck(a)linux.vnet.ibm.com>
AuthorDate: Fri, 5 Mar 2010 15:03:26 -0800
Committer: Ingo Molnar <mingo(a)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(a)linux.vnet.ibm.com>
Cc: laijs(a)cn.fujitsu.com
Cc: dipankar(a)in.ibm.com
Cc: mathieu.desnoyers(a)polymtl.ca
Cc: josh(a)joshtriplett.org
Cc: dvhltc(a)us.ibm.com
Cc: niv(a)us.ibm.com
Cc: peterz(a)infradead.org
Cc: rostedt(a)goodmis.org
Cc: Valdis.Kletnieks(a)vt.edu
Cc: dhowells(a)redhat.com
LKML-Reference: <1267830207-9474-2-git-send-email-paulmck(a)linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo(a)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 */

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Prev: [tip:tracing/urgent] function-graph: Add tracing_thresh support to function_graph tracer
Next: [tip:perf/urgent] perf: export perf_trace_regs and perf_arch_fetch_caller_regs