122 lines
3.3 KiB
Diff
122 lines
3.3 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 16 Feb 2018 11:45:13 +0100
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Subject: [PATCH] RCU: skip the "schedule() in RCU section" warning on UP,
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too
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.16/older/patches-4.16.8-rt3.tar.xz
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In "RCU: we need to skip that warning but only on sleeping locks" we
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skipped a warning on SMP systems in case we schedule out in a RCU
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section while attempt to obtain a sleeping lock. This is also required
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on UP systems.
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In order to do so, I introduce a tiny version of migrate_disable() +
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_enable() which only update the counters which we then can check against
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on RT && !SMP.
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Cc: stable-rt@vger.kernel.org
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Reported-by: Grygorii Strashko <grygorii.strashko@ti.com>
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Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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include/linux/preempt.h | 9 +++++++++
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include/linux/sched.h | 6 ++++++
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kernel/rcu/tree_plugin.h | 2 +-
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kernel/sched/core.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
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4 files changed, 61 insertions(+), 1 deletion(-)
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--- a/include/linux/preempt.h
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+++ b/include/linux/preempt.h
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@@ -211,6 +211,15 @@ extern void migrate_enable(void);
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int __migrate_disabled(struct task_struct *p);
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+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
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+
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+extern void migrate_disable(void);
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+extern void migrate_enable(void);
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+static inline int __migrate_disabled(struct task_struct *p)
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+{
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+ return 0;
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+}
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+
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#else
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#define migrate_disable() barrier()
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#define migrate_enable() barrier()
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -604,6 +604,12 @@ struct task_struct {
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# ifdef CONFIG_SCHED_DEBUG
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int migrate_disable_atomic;
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# endif
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+
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+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
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+ int migrate_disable;
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+# ifdef CONFIG_SCHED_DEBUG
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+ int migrate_disable_atomic;
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+# endif
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#endif
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#ifdef CONFIG_PREEMPT_RCU
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--- a/kernel/rcu/tree_plugin.h
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+++ b/kernel/rcu/tree_plugin.h
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@@ -328,7 +328,7 @@ static void rcu_preempt_note_context_swi
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int mg_counter = 0;
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lockdep_assert_irqs_disabled();
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-#if defined(CONFIG_PREEMPT_COUNT) && defined(CONFIG_SMP)
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+#if defined(CONFIG_PREEMPT_RT_BASE)
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mg_counter = t->migrate_disable;
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#endif
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WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !mg_counter);
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--- a/kernel/sched/core.c
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+++ b/kernel/sched/core.c
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@@ -7278,4 +7278,49 @@ void migrate_enable(void)
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preempt_enable();
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}
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EXPORT_SYMBOL(migrate_enable);
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+
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+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE)
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+void migrate_disable(void)
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+{
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+ struct task_struct *p = current;
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+
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+ if (in_atomic() || irqs_disabled()) {
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+#ifdef CONFIG_SCHED_DEBUG
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+ p->migrate_disable_atomic++;
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+#endif
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+ return;
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+ }
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+#ifdef CONFIG_SCHED_DEBUG
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+ if (unlikely(p->migrate_disable_atomic)) {
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+ tracing_off();
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+ WARN_ON_ONCE(1);
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+ }
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+#endif
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+
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+ p->migrate_disable++;
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+}
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+EXPORT_SYMBOL(migrate_disable);
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+
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+void migrate_enable(void)
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+{
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+ struct task_struct *p = current;
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+
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+ if (in_atomic() || irqs_disabled()) {
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+#ifdef CONFIG_SCHED_DEBUG
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+ p->migrate_disable_atomic--;
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+#endif
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+ return;
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+ }
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+
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+#ifdef CONFIG_SCHED_DEBUG
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+ if (unlikely(p->migrate_disable_atomic)) {
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+ tracing_off();
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+ WARN_ON_ONCE(1);
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+ }
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+#endif
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+
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+ WARN_ON_ONCE(p->migrate_disable <= 0);
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+ p->migrate_disable--;
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+}
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+EXPORT_SYMBOL(migrate_enable);
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#endif
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