rcu: Rework preemptible expedited bitmask handling
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Fri, 13 Feb 2015 18:52:28 +0000 (10:52 -0800)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Thu, 12 Mar 2015 22:18:42 +0000 (15:18 -0700)
commit8eb74b2b291e7bf6aa59fcb4e59f236382f00bf5
tree07abd44430c52bfe2f76ba62188b7958c3910c35
parent999c286347538388170f919146d7cfa58689472e
rcu: Rework preemptible expedited bitmask handling

Currently, the rcu_node tree ->expmask bitmasks are initially set to
reflect the online CPUs.  This is pointless, because only the CPUs
preempted within RCU read-side critical sections by the preceding
synchronize_sched_expedited() need to be tracked.  This commit therefore
instead sets up these bitmasks based on the state of the ->blkd_tasks
lists.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
kernel/rcu/tree_plugin.h