tree af8915695057dad40b62a592a99d608de815d9d3
parent 3382adbc1bb8c80ea512243acf6059564287620b
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1426532032 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1432756681 -0700

rcu: Force wakeup of rcu_gp_kthread at grace-period end

The rcu_gp_kthread_wake() refuses to do a wakeup unless at least
one of the ->gp_flags bits are set, which normally will not be the
case when the last quiescent state is reported.  This results in
up to a 3-jiffy delay given default Kconfig settings.  This commit
therefore has rcu_report_qs_rsp() set RCU_GP_FLAG_FQS before invoking
rcu_gp_kthread_wake() in order to force a more immediate wakeup at
grace-period end, thus reducing grace-period latencies.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>