]> git.baikalelectronics.ru Git - kernel.git/commit
rcu: Allow RCU grace-period cleanup to be preempted
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Thu, 21 Jun 2012 15:19:05 +0000 (08:19 -0700)
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Sun, 23 Sep 2012 14:41:53 +0000 (07:41 -0700)
commite71bc39896e4204fa247df6d48c19924ffd665ad
tree2bc16cb69d397440c5082fd451d64db6efa67017
parente3ef0567f2b18a7a2f4092942a9f4b1062f4b209
rcu: Allow RCU grace-period cleanup to be preempted

RCU grace-period cleanup is currently carried out with interrupts
disabled, which can result in excessive latency spikes on large systems
(many hundreds or thousands of CPUs).  This patch therefore makes the
RCU grace-period cleanup be preemptible, including voluntary preemption
points, which should eliminate those latency spikes.  Similar spikes from
forcing of quiescent states will be dealt with similarly by later patches.

Updated to replace uses of spin_lock_irqsave() with spin_lock_irq(), as
suggested by Peter Zijlstra.

Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
kernel/rcutree.c