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linux/debian/patches/features/all/rt/0162-sched-migrate-disable....

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From 962439d3528eb950db4703f755a73bf015482ee7 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 16 Jun 2011 13:26:08 +0200
Subject: [PATCH 162/278] sched-migrate-disable.patch
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/preempt.h | 8 +++++
include/linux/sched.h | 13 +++++--
include/linux/smp.h | 1 -
kernel/sched.c | 88 ++++++++++++++++++++++++++++++++++++++++++++---
lib/smp_processor_id.c | 6 ++--
5 files changed, 104 insertions(+), 12 deletions(-)
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 29db25f..363e5e2 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -108,6 +108,14 @@ do { \
#endif /* CONFIG_PREEMPT_COUNT */
+#ifdef CONFIG_SMP
+extern void migrate_disable(void);
+extern void migrate_enable(void);
+#else
+# define migrate_disable() do { } while (0)
+# define migrate_enable() do { } while (0)
+#endif
+
#ifdef CONFIG_PREEMPT_RT_FULL
# define preempt_disable_rt() preempt_disable()
# define preempt_enable_rt() preempt_enable()
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 34ebf9e..3e8b05e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1263,6 +1263,7 @@ struct task_struct {
#endif
unsigned int policy;
+ int migrate_disable;
cpumask_t cpus_allowed;
#ifdef CONFIG_PREEMPT_RCU
@@ -1602,9 +1603,6 @@ struct task_struct {
#endif
};
-/* Future-safe accessor for struct task_struct's cpus_allowed. */
-#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
-
#ifdef CONFIG_PREEMPT_RT_FULL
static inline bool cur_pf_disabled(void) { return current->pagefault_disabled; }
#else
@@ -2695,6 +2693,15 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
#endif /* CONFIG_SMP */
+/* Future-safe accessor for struct task_struct's cpus_allowed. */
+static inline const struct cpumask *tsk_cpus_allowed(struct task_struct *p)
+{
+ if (p->migrate_disable)
+ return cpumask_of(task_cpu(p));
+
+ return &p->cpus_allowed;
+}
+
extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
diff --git a/include/linux/smp.h b/include/linux/smp.h
index e6c58d8..94c8430 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -80,7 +80,6 @@ void __smp_call_function_single(int cpuid, struct call_single_data *data,
int smp_call_function_any(const struct cpumask *mask,
smp_call_func_t func, void *info, int wait);
-
/*
* Generic and arch helpers
*/
diff --git a/kernel/sched.c b/kernel/sched.c
index 425a466..ee24260 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6410,11 +6410,12 @@ static inline void sched_init_granularity(void)
#ifdef CONFIG_SMP
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
- if (p->sched_class && p->sched_class->set_cpus_allowed)
- p->sched_class->set_cpus_allowed(p, new_mask);
-
+ if (!p->migrate_disable) {
+ if (p->sched_class && p->sched_class->set_cpus_allowed)
+ p->sched_class->set_cpus_allowed(p, new_mask);
+ p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
+ }
cpumask_copy(&p->cpus_allowed, new_mask);
- p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
}
/*
@@ -6465,7 +6466,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
do_set_cpus_allowed(p, new_mask);
/* Can the task run on the task's current CPU? If so, we're done */
- if (cpumask_test_cpu(task_cpu(p), new_mask))
+ if (cpumask_test_cpu(task_cpu(p), new_mask) || p->migrate_disable)
goto out;
dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
@@ -6484,6 +6485,83 @@ out:
}
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+void migrate_disable(void)
+{
+ struct task_struct *p = current;
+ const struct cpumask *mask;
+ unsigned long flags;
+ struct rq *rq;
+
+ preempt_disable();
+ if (p->migrate_disable) {
+ p->migrate_disable++;
+ preempt_enable();
+ return;
+ }
+
+ pin_current_cpu();
+ if (unlikely(!scheduler_running)) {
+ p->migrate_disable = 1;
+ preempt_enable();
+ return;
+ }
+ rq = task_rq_lock(p, &flags);
+ p->migrate_disable = 1;
+ mask = tsk_cpus_allowed(p);
+
+ WARN_ON(!cpumask_test_cpu(smp_processor_id(), mask));
+
+ if (!cpumask_equal(&p->cpus_allowed, mask)) {
+ if (p->sched_class->set_cpus_allowed)
+ p->sched_class->set_cpus_allowed(p, mask);
+ p->rt.nr_cpus_allowed = cpumask_weight(mask);
+ }
+ task_rq_unlock(rq, p, &flags);
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(migrate_disable);
+
+void migrate_enable(void)
+{
+ struct task_struct *p = current;
+ const struct cpumask *mask;
+ unsigned long flags;
+ struct rq *rq;
+
+ WARN_ON_ONCE(p->migrate_disable <= 0);
+
+ preempt_disable();
+ if (p->migrate_disable > 1) {
+ p->migrate_disable--;
+ preempt_enable();
+ return;
+ }
+
+ if (unlikely(!scheduler_running)) {
+ p->migrate_disable = 0;
+ unpin_current_cpu();
+ preempt_enable();
+ return;
+ }
+
+ rq = task_rq_lock(p, &flags);
+ p->migrate_disable = 0;
+ mask = tsk_cpus_allowed(p);
+
+ WARN_ON(!cpumask_test_cpu(smp_processor_id(), mask));
+
+ if (!cpumask_equal(&p->cpus_allowed, mask)) {
+ if (p->sched_class->set_cpus_allowed)
+ p->sched_class->set_cpus_allowed(p, mask);
+ p->rt.nr_cpus_allowed = cpumask_weight(mask);
+ }
+
+ task_rq_unlock(rq, p, &flags);
+ unpin_current_cpu();
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(migrate_enable);
+
/*
* Move (not current) task off this cpu, onto dest cpu. We're doing
* this because either it can't run here any more (set_cpus_allowed()
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 503f087..60a7569 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -39,9 +39,9 @@ notrace unsigned int debug_smp_processor_id(void)
if (!printk_ratelimit())
goto out_enable;
- printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
- "code: %s/%d\n",
- preempt_count() - 1, current->comm, current->pid);
+ printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x %08x] "
+ "code: %s/%d\n", preempt_count() - 1,
+ current->migrate_disable, current->comm, current->pid);
print_symbol("caller is %s\n", (long)__builtin_return_address(0));
dump_stack();
--
1.7.10
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