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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-11-25 18:56:00 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-12-04 12:26:54 -0800
commit3e42ec1aa716f10c68294b8492ae3ea684528699 (patch)
treebe431b624157914bd08d965fed9423fe267ff927 /kernel/rcu/update.c
parent967dcb8fe6a9a75be346400539261e0416baf370 (diff)
downloadlinux-sh-3e42ec1aa716f10c68294b8492ae3ea684528699.tar.gz
rcu: Allow expedited grace periods to be disabled at init
Expedited grace periods can speed up boot, but are undesirable in aggressive real-time systems. This commit therefore introduces a kernel parameter rcupdate.rcu_normal_after_boot that disables expedited grace periods just before init is spawned. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/update.c')
-rw-r--r--kernel/rcu/update.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 8fccda3a794d..12b91f5a60a6 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -63,6 +63,9 @@ MODULE_ALIAS("rcupdate");
module_param(rcu_expedited, int, 0);
module_param(rcu_normal, int, 0);
+static int rcu_normal_after_boot;
+module_param(rcu_normal_after_boot, int, 0);
+
#if defined(CONFIG_DEBUG_LOCK_ALLOC) && defined(CONFIG_PREEMPT_COUNT)
/**
* rcu_read_lock_sched_held() - might we be in RCU-sched read-side critical section?
@@ -178,6 +181,8 @@ void rcu_end_inkernel_boot(void)
{
if (IS_ENABLED(CONFIG_RCU_EXPEDITE_BOOT))
rcu_unexpedite_gp();
+ if (rcu_normal_after_boot)
+ WRITE_ONCE(rcu_normal, 1);
}
#ifdef CONFIG_PREEMPT_RCU