From: Byungchul Park <byungchul.park@lge.com>
To: jiangshanlai@gmail.com, paulmck@linux.vnet.ibm.com,
josh@joshtriplett.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com
Cc: linux-kernel@vger.kernel.org, kernel-team@lge.com
Subject: [PATCH] rcu: Report a quiescent state when it's exactly in the state
Date: Fri, 11 May 2018 17:30:34 +0900 [thread overview]
Message-ID: <1526027434-21237-1-git-send-email-byungchul.park@lge.com> (raw)
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>
---
include/linux/rcupdate.h | 4 ++--
kernel/rcu/tiny.c | 6 +++---
kernel/rcu/tree.c | 4 ++--
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ee8cf5fc..7432261 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -195,8 +195,8 @@ static inline void exit_tasks_rcu_finish(void) { }
*/
#define cond_resched_tasks_rcu_qs() \
do { \
- if (!cond_resched()) \
- rcu_note_voluntary_context_switch_lite(current); \
+ rcu_note_voluntary_context_switch_lite(current); \
+ cond_resched(); \
} while (0)
/*
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index a64eee0..68d2332 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -120,12 +120,12 @@ void rcu_bh_qs(void)
*/
void rcu_check_callbacks(int user)
{
- if (user)
+ if (user) {
rcu_sched_qs();
- else if (!in_softirq())
rcu_bh_qs();
- if (user)
rcu_note_voluntary_context_switch(current);
+ } else if (!in_softirq())
+ rcu_bh_qs();
}
/*
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 36075dd..1abe29a 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2595,6 +2595,7 @@ void rcu_check_callbacks(int user)
rcu_sched_qs();
rcu_bh_qs();
+ rcu_note_voluntary_context_switch(current);
} else if (!in_softirq()) {
@@ -2610,8 +2611,7 @@ 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"));
}
--
1.9.1
next reply other threads:[~2018-05-11 8:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-11 8:30 Byungchul Park [this message]
2018-05-11 12:57 ` [PATCH] rcu: Report a quiescent state when it's exactly in the state Byungchul Park
2018-05-11 16:17 ` Paul E. McKenney
2018-05-11 16:23 ` Steven Rostedt
2018-05-11 16:25 ` Steven Rostedt
2018-05-11 16:27 ` Steven Rostedt
2018-05-11 17:27 ` Paul E. McKenney
2018-05-11 17:29 ` Steven Rostedt
2018-05-11 22:41 ` Joel Fernandes
2018-05-12 5:08 ` Paul E. McKenney
2018-05-12 6:30 ` Joel Fernandes
2018-05-12 14:41 ` Paul E. McKenney
2018-05-12 17:26 ` Steven Rostedt
2018-05-14 3:11 ` Byungchul Park
2018-05-13 0:09 ` Joel Fernandes
2018-05-14 2:59 ` Byungchul Park
2018-05-14 14:25 ` Byungchul Park
2018-05-14 21:04 ` Paul E. McKenney
2018-05-15 0:18 ` Byungchul Park
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