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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-01-12 08:33:37 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-03-31 13:34:03 -0700
commit28728dd310d48834cd486dac3cac9ae96b9deb96 (patch)
tree507e605d6e89567f62d8148b779a45d6f369d52e /kernel/rcu/tree.c
parent274529ba9bda86c91c2c06da3a641aaf617dd30f (diff)
downloadlinux-sh-28728dd310d48834cd486dac3cac9ae96b9deb96.tar.gz
rcu: Make expedited RCU-sched grace period immediately detect idle
Currently, sync_sched_exp_handler() will force a reschedule unless this CPU has already checked in or unless a reschedule has already been called for. This is clearly wasteful if sync_sched_exp_handler() interrupted an idle CPU, so this commit immediately reports the quiescent state in that case. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.c')
-rw-r--r--kernel/rcu/tree.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 531a328076bd..5f4336fadc28 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3649,6 +3649,11 @@ static void sync_sched_exp_handler(void *data)
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask) ||
__this_cpu_read(rcu_sched_data.cpu_no_qs.b.exp))
return;
+ if (rcu_is_cpu_rrupt_from_idle()) {
+ rcu_report_exp_rdp(&rcu_sched_state,
+ this_cpu_ptr(&rcu_sched_data), true);
+ return;
+ }
__this_cpu_write(rcu_sched_data.cpu_no_qs.b.exp, true);
resched_cpu(smp_processor_id());
}