| Message ID | 1320265849-5744-4-git-send-email-paulmck@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Commit | 7077714ec4940a6c5b1189c3afb4f47bf49ad877 |
| Headers | show |
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 7986053..708dc57 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1910,7 +1910,7 @@ void synchronize_sched_expedited(void) * grace period works for us. */ get_online_cpus(); - snap = atomic_read(&sync_sched_expedited_started) - 1; + snap = atomic_read(&sync_sched_expedited_started); smp_mb(); /* ensure read is before try_stop_cpus(). */ }
When synchronize_sched_expedited() takes its second and subsequent snapshots of sync_sched_expedited_started, it subtracts 1. This means that the concurrent caller of synchronize_sched_expedited() that incremented to that value sees our successful completion, it will not be able to take advantage of it. This restriction is pointless, given that our full expedited grace period would have happened after the other guy started, and thus should be able to serve as a proxy for the other guy successfully executing try_stop_cpus(). This commit therefore removes the subtraction of 1. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcutree_plugin.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)