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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2009-09-13 09:15:10 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-18 00:06:33 +0200 |
| commit | c3422bea5f09b0e85704f51f2b01271630b8940b (patch) | |
| tree | fc4a18241b0f7f5d71211f6787428197769cb9f5 /kernel/rcupdate.c | |
| parent | b0e165c035b13e1074fa0b555318bd9cb7102558 (diff) | |
| download | lwn-c3422bea5f09b0e85704f51f2b01271630b8940b.tar.gz lwn-c3422bea5f09b0e85704f51f2b01271630b8940b.zip | |
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 <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
LKML-Reference: <12528585111945-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcupdate.c')
0 files changed, 0 insertions, 0 deletions