rcu/nocb: Unify timers
Now that nocb_timer and nocb_bypass_timer have become very similar,
merge them together. A new RCU_NOCB_WAKE_BYPASS wake level is introduced.
As a result, timers perform all kinds of deferred wake ups but other
deferred wakeup callsites only handle non-bypass wakeups in order not
to wake up rcuo too early.
The timer also performs the full barrier all the time to order
timer_pending() and callback enqueue although the path performing
RCU_NOCB_WAKE_FORCE that makes use of it is debatable. It should also
test against the rdp leader instead of the current rdp.
The permanent full barrier shouldn't bring visible overhead since the
timers almost never fire.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
3 files changed
