tree 1339bc7b3bef920b4641a5af2f182e9dfa2a6632
parent 66f75a5d028beaf67c931435fdc3e7823125730c
author Paul E. McKenney <paul.mckenney@linaro.org> 1332889328 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1335995003 -0700

rcu: Move PREEMPT_RCU preemption to switch_to() invocation

Currently, PREEMPT_RCU readers are enqueued upon entry to the scheduler.
This is inefficient because enqueuing is required only if there is a
context switch, and entry to the scheduler does not guarantee a context
switch.

The commit therefore moves the enqueuing to immediately precede the
call to switch_to() from the scheduler.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>