From: Scott Wood <swood@redhat.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
"Paul E . McKenney" <paulmck@linux.ibm.com>,
Joel Fernandes <joel@joelfernandes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Clark Williams <williams@redhat.com>,
Scott Wood <swood@redhat.com>
Subject: [PATCH RT v3 3/5] sched: migrate_dis/enable: Use rt_invol_sleep
Date: Wed, 11 Sep 2019 17:57:27 +0100 [thread overview]
Message-ID: <20190911165729.11178-4-swood@redhat.com> (raw)
In-Reply-To: <20190911165729.11178-1-swood@redhat.com>
Without this, rcu_note_context_switch() will complain if an RCU read lock
is held when migrate_enable() calls stop_one_cpu(). Likewise when
migrate_disable() calls pin_current_cpu() which calls __read_rt_lock() --
which bypasses the part of the mutex code that calls rt_invol_sleep_inc().
Signed-off-by: Scott Wood <swood@redhat.com>
---
v3: Add to pin_current_cpu as well
include/linux/sched.h | 4 ++--
kernel/cpu.c | 2 ++
kernel/rcu/tree_plugin.h | 2 +-
kernel/sched/core.c | 4 ++++
4 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index edc93b74f7d8..ecf5cbb23335 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -673,7 +673,7 @@ struct task_struct {
int migrate_disable_atomic;
# endif
#endif
-#ifdef CONFIG_PREEMPT_RT_FULL
+#ifdef CONFIG_PREEMPT_RT_BASE
/* Task is blocking due to RT-specific mechanisms, not voluntarily */
int rt_invol_sleep;
#endif
@@ -1882,7 +1882,7 @@ static __always_inline bool need_resched(void)
return unlikely(tif_need_resched());
}
-#ifdef CONFIG_PREEMPT_RT_FULL
+#ifdef CONFIG_PREEMPT_RT_BASE
static inline void rt_invol_sleep_inc(void)
{
current->rt_invol_sleep++;
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 885a195dfbe0..32c6175b63b6 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -308,7 +308,9 @@ void pin_current_cpu(void)
preempt_lazy_enable();
preempt_enable();
+ rt_invol_sleep_inc();
__read_rt_lock(cpuhp_pin);
+ rt_invol_sleep_dec();
preempt_disable();
preempt_lazy_disable();
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 0da4b975cd71..6d92dafeeca5 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -292,7 +292,7 @@ void rcu_note_context_switch(bool preempt)
barrier(); /* Avoid RCU read-side critical sections leaking down. */
trace_rcu_utilization(TPS("Start context switch"));
lockdep_assert_irqs_disabled();
-#if defined(CONFIG_PREEMPT_RT_FULL)
+#if defined(CONFIG_PREEMPT_RT_BASE)
rt_invol = t->rt_invol_sleep;
#endif
WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !rt_invol);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e1bdd7f9be05..a151332474d8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7405,7 +7405,11 @@ void migrate_enable(void)
unpin_current_cpu();
preempt_lazy_enable();
preempt_enable();
+
+ rt_invol_sleep_inc();
stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
+ rt_invol_sleep_dec();
+
return;
}
}
--
1.8.3.1
next prev parent reply other threads:[~2019-09-11 16:57 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 16:57 [PATCH RT v3 0/5] RCU fixes Scott Wood
2019-09-11 16:57 ` [PATCH RT v3 1/5] rcu: Acquire RCU lock when disabling BHs Scott Wood
2019-09-12 22:09 ` Joel Fernandes
2019-09-17 7:44 ` Sebastian Andrzej Siewior
2019-09-17 14:06 ` Scott Wood
2019-09-17 14:42 ` Sebastian Andrzej Siewior
2019-09-17 16:12 ` Scott Wood
2019-09-23 16:41 ` Sebastian Andrzej Siewior
2019-09-11 16:57 ` [PATCH RT v3 2/5] sched: Rename sleeping_lock to rt_invol_sleep Scott Wood
2019-09-17 7:52 ` Sebastian Andrzej Siewior
2019-09-11 16:57 ` Scott Wood [this message]
2019-09-17 7:59 ` [PATCH RT v3 3/5] sched: migrate_dis/enable: Use rt_invol_sleep Sebastian Andrzej Siewior
2019-09-17 14:06 ` Scott Wood
2019-09-23 16:59 ` Scott Wood
2019-09-23 17:52 ` Sebastian Andrzej Siewior
2019-09-24 11:21 ` Sebastian Andrzej Siewior
2019-09-24 13:53 ` Scott Wood
2019-09-24 15:25 ` Sebastian Andrzej Siewior
2019-09-24 15:47 ` Scott Wood
2019-09-24 16:05 ` Sebastian Andrzej Siewior
2019-09-24 16:35 ` Scott Wood
2019-10-04 16:45 ` Sebastian Andrzej Siewior
2019-09-11 16:57 ` [PATCH RT v3 4/5] rcu: Disable use_softirq on PREEMPT_RT Scott Wood
2019-09-12 21:38 ` Joel Fernandes
2019-09-12 22:19 ` Joel Fernandes
2019-09-17 9:31 ` Sebastian Andrzej Siewior
2019-09-17 14:08 ` Scott Wood
2019-09-11 16:57 ` [PATCH RT v3 5/5] rcutorture: Avoid problematic critical section nesting on RT Scott Wood
2019-09-12 22:17 ` Joel Fernandes
2019-09-16 16:55 ` Scott Wood
2019-09-17 10:07 ` Sebastian Andrzej Siewior
2019-09-17 14:36 ` Scott Wood
2019-09-17 14:50 ` Sebastian Andrzej Siewior
2019-09-17 16:32 ` Scott Wood
2019-09-23 16:25 ` Sebastian Andrzej Siewior
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