129 lines
3.7 KiB
Diff
129 lines
3.7 KiB
Diff
From cd4338213f1bf8c900a9fa4c00555ef48034fd13 Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Mon, 19 Jun 2017 09:55:47 +0200
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Subject: [PATCH 305/365] sched/migrate disable: handle updated task-mask
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mg-dis section
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If task's cpumask changes while in the task is in a migrate_disable()
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section then we don't react on it after a migrate_enable(). It matters
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however if current CPU is no longer part of the cpumask. We also miss
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the ->set_cpus_allowed() callback.
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This patch fixes it by setting task->migrate_disable_update once we this
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"delayed" hook.
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This bug was introduced while fixing unrelated issue in
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migrate_disable() in v4.4-rt3 (update_migrate_disable() got removed
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during that).
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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include/linux/sched.h | 1 +
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kernel/sched/core.c | 59 ++++++++++++++++++++++++++++++++++++++-----
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2 files changed, 54 insertions(+), 6 deletions(-)
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diff --git a/include/linux/sched.h b/include/linux/sched.h
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index d92212f33e25..4b258706f687 100644
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -1718,6 +1718,7 @@ struct task_struct {
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unsigned int policy;
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#ifdef CONFIG_PREEMPT_RT_FULL
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int migrate_disable;
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+ int migrate_disable_update;
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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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diff --git a/kernel/sched/core.c b/kernel/sched/core.c
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index bff8350da2fd..874658e9d15a 100644
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--- a/kernel/sched/core.c
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+++ b/kernel/sched/core.c
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@@ -1191,18 +1191,14 @@ void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_ma
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p->nr_cpus_allowed = cpumask_weight(new_mask);
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}
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-void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
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+static void __do_set_cpus_allowed_tail(struct task_struct *p,
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+ const struct cpumask *new_mask)
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{
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struct rq *rq = task_rq(p);
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bool queued, running;
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lockdep_assert_held(&p->pi_lock);
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- if (__migrate_disabled(p)) {
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- cpumask_copy(&p->cpus_allowed, new_mask);
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- return;
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- }
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-
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queued = task_on_rq_queued(p);
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running = task_current(rq, p);
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@@ -1225,6 +1221,20 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
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set_curr_task(rq, p);
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}
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+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
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+{
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+ if (__migrate_disabled(p)) {
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+ lockdep_assert_held(&p->pi_lock);
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+
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+ cpumask_copy(&p->cpus_allowed, new_mask);
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+#if defined(CONFIG_PREEMPT_RT_FULL) && defined(CONFIG_SMP)
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+ p->migrate_disable_update = 1;
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+#endif
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+ return;
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+ }
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+ __do_set_cpus_allowed_tail(p, new_mask);
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+}
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+
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static DEFINE_PER_CPU(struct cpumask, sched_cpumasks);
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static DEFINE_MUTEX(sched_down_mutex);
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static cpumask_t sched_down_cpumask;
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@@ -3608,6 +3618,43 @@ void migrate_enable(void)
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*/
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p->migrate_disable = 0;
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+ if (p->migrate_disable_update) {
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+ struct rq *rq;
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+ struct rq_flags rf;
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+
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+ rq = task_rq_lock(p, &rf);
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+ update_rq_clock(rq);
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+
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+ __do_set_cpus_allowed_tail(p, &p->cpus_allowed);
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+ task_rq_unlock(rq, p, &rf);
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+
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+ p->migrate_disable_update = 0;
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+
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+ WARN_ON(smp_processor_id() != task_cpu(p));
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+ if (!cpumask_test_cpu(task_cpu(p), &p->cpus_allowed)) {
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+ const struct cpumask *cpu_valid_mask = cpu_active_mask;
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+ struct migration_arg arg;
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+ unsigned int dest_cpu;
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+
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+ if (p->flags & PF_KTHREAD) {
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+ /*
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+ * Kernel threads are allowed on online && !active CPUs
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+ */
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+ cpu_valid_mask = cpu_online_mask;
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+ }
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+ dest_cpu = cpumask_any_and(cpu_valid_mask, &p->cpus_allowed);
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+ arg.task = p;
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+ arg.dest_cpu = dest_cpu;
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+
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+ unpin_current_cpu();
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+ preempt_lazy_enable();
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+ preempt_enable();
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+ stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
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+ tlb_migrate_finish(p->mm);
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+ return;
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+ }
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+ }
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+
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unpin_current_cpu();
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preempt_enable();
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preempt_lazy_enable();
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--
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2.28.0
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