tree b42541168d50567df146c2e95d5ab15b1dc3af14
parent b08517c76d764c373c232cd309ed058c98705219
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1441266302 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1444258970 -0700

rcu: Better hotplug handling for synchronize_sched_expedited()

Earlier versions of synchronize_sched_expedited() can prematurely end
grace periods due to the fact that a CPU marked as cpu_is_offline()
can still be using RCU read-side critical sections during the time that
CPU makes its last pass through the scheduler and into the idle loop
and during the time that a given CPU is in the process of coming online.
This commit therefore eliminates this window by adding additional
interaction with the CPU-hotplug operations.

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