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authorByungchul Park <byungchul.park@lge.com>2018-05-11 17:30:34 +0900
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2018-07-12 15:39:12 -0700
commit07f27570dcd148a5f4de7dc3513c1d1cd069b362 (patch)
tree55e1329fcf74946468664d7acce77e1bbefbc9ea /kernel/rcu
parent3949fa9bac090ad217534c30bc3b6572289abf21 (diff)
rcu: Improve rcu_note_voluntary_context_switch() reporting
We expect a quiescent state of TASKS_RCU when cond_resched_tasks_rcu_qs() is called, no matter whether it actually be scheduled or not. However, it currently doesn't report the quiescent state when the task enters into __schedule() as it's called with preempt = true. So make it report the quiescent state unconditionally when cond_resched_tasks_rcu_qs() is called. And in TINY_RCU, even though the quiescent state of rcu_bh also should be reported when the tick interrupt comes from user, it doesn't. So make it reported. Lastly in TREE_RCU, rcu_note_voluntary_context_switch() should be reported when the tick interrupt comes from not only user but also idle, as an extended quiescent state. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Simplify rcutiny portion given no RCU-tasks for !PREEMPT. ]
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tiny.c4
-rw-r--r--kernel/rcu/tree.c4
2 files changed, 3 insertions, 5 deletions
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index a64eee0db39e..befc9321a89c 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -122,10 +122,8 @@ void rcu_check_callbacks(int user)
{
if (user)
rcu_sched_qs();
- else if (!in_softirq())
+ if (user || !in_softirq())
rcu_bh_qs();
- if (user)
- rcu_note_voluntary_context_switch(current);
}
/*
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d3333ee2c6f5..19beabe73629 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2645,6 +2645,7 @@ void rcu_check_callbacks(int user)
rcu_sched_qs();
rcu_bh_qs();
+ rcu_note_voluntary_context_switch(current);
} else if (!in_softirq()) {
@@ -2660,8 +2661,7 @@ void rcu_check_callbacks(int user)
rcu_preempt_check_callbacks();
if (rcu_pending())
invoke_rcu_core();
- if (user)
- rcu_note_voluntary_context_switch(current);
+
trace_rcu_utilization(TPS("End scheduler-tick"));
}