rcu: Simplify rcu_read_unlock_special() quiescent-state accounting

The earlier approach required two scheduling-clock ticks to note an
preemptable-RCU quiescent state in the situation in which the
scheduling-clock interrupt is unlucky enough to always interrupt an
RCU read-side critical section.

With this change, the quiescent state is instead noted by the
outermost rcu_read_unlock() immediately following the first
scheduling-clock tick, or, alternatively, by the first subsequent
context switch.  Therefore, this change also speeds up grace
periods.

Suggested-by: Josh Triplett <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Cc: [email protected]
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LKML-Reference: <12528585111945-git-send-email->
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions