sched/numa: Remove the NUMA sched_feature

[firefly-linux-kernel-4.4.55.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3595403921bd5be10c3e5e591bf04916e654423d..e0bd88b26a2773e9a3a7f06ecb8d7282eb33bca6 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -621,18 +621,21 @@ int get_nohz_timer_target(void)
        int i, cpu = smp_processor_id();
        struct sched_domain *sd;
 
-       if (!idle_cpu(cpu))
+       if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu))
                return cpu;
 
        rcu_read_lock();
        for_each_domain(cpu, sd) {
                for_each_cpu(i, sched_domain_span(sd)) {
-                       if (!idle_cpu(i)) {
+                       if (!idle_cpu(i) && is_housekeeping_cpu(cpu)) {
                                cpu = i;
                                goto unlock;
                        }
                }
        }
+
+       if (!is_housekeeping_cpu(cpu))
+               cpu = housekeeping_any_cpu();
 unlock:
        rcu_read_unlock();
        return cpu;
@@ -2112,22 +2115,12 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
 }
 
 #ifdef CONFIG_NUMA_BALANCING
-#ifdef CONFIG_SCHED_DEBUG
-void set_numabalancing_state(bool enabled)
-{
-       if (enabled)
-               sched_feat_set("NUMA");
-       else
-               sched_feat_set("NO_NUMA");
-}
-#else
-__read_mostly bool numabalancing_enabled;
+__read_mostly bool sched_numa_balancing;
 
 void set_numabalancing_state(bool enabled)
 {
-       numabalancing_enabled = enabled;
+       sched_numa_balancing = enabled;
 }
-#endif /* CONFIG_SCHED_DEBUG */
 
 #ifdef CONFIG_PROC_SYSCTL
 int sysctl_numa_balancing(struct ctl_table *table, int write,
@@ -2135,7 +2128,7 @@ int sysctl_numa_balancing(struct ctl_table *table, int write,
 {
        struct ctl_table t;
        int err;
-       int state = numabalancing_enabled;
+       int state = sched_numa_balancing;
 
        if (write && !capable(CAP_SYS_ADMIN))
                return -EPERM;
@@ -5178,24 +5171,47 @@ static void migrate_tasks(struct rq *dead_rq)
                        break;
 
                /*
-                * Ensure rq->lock covers the entire task selection
-                * until the migration.
+                * pick_next_task assumes pinned rq->lock.
                 */
                lockdep_pin_lock(&rq->lock);
                next = pick_next_task(rq, &fake_task);
                BUG_ON(!next);
                next->sched_class->put_prev_task(rq, next);
 
+               /*
+                * Rules for changing task_struct::cpus_allowed are holding
+                * both pi_lock and rq->lock, such that holding either
+                * stabilizes the mask.
+                *
+                * Drop rq->lock is not quite as disastrous as it usually is
+                * because !cpu_active at this point, which means load-balance
+                * will not interfere. Also, stop-machine.
+                */
+               lockdep_unpin_lock(&rq->lock);
+               raw_spin_unlock(&rq->lock);
+               raw_spin_lock(&next->pi_lock);
+               raw_spin_lock(&rq->lock);
+
+               /*
+                * Since we're inside stop-machine, _nothing_ should have
+                * changed the task, WARN if weird stuff happened, because in
+                * that case the above rq->lock drop is a fail too.
+                */
+               if (WARN_ON(task_rq(next) != rq || !task_on_rq_queued(next))) {
+                       raw_spin_unlock(&next->pi_lock);
+                       continue;
+               }
+
                /* Find suitable destination for @next, with force if needed. */
                dest_cpu = select_fallback_rq(dead_rq->cpu, next);
 
-               lockdep_unpin_lock(&rq->lock);
                rq = __migrate_task(rq, next, dest_cpu);
                if (rq != dead_rq) {
                        raw_spin_unlock(&rq->lock);
                        rq = dead_rq;
                        raw_spin_lock(&rq->lock);
                }
+               raw_spin_unlock(&next->pi_lock);
        }
 
        rq->stop = stop;
@@ -7695,7 +7711,7 @@ void sched_move_task(struct task_struct *tsk)
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
        if (tsk->sched_class->task_move_group)
-               tsk->sched_class->task_move_group(tsk, queued);
+               tsk->sched_class->task_move_group(tsk);
        else
 #endif
                set_task_rq(tsk, task_cpu(tsk));
@@ -8167,14 +8183,6 @@ static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
                            struct cgroup_subsys_state *old_css,
                            struct task_struct *task)
 {
-       /*
-        * cgroup_exit() is called in the copy_process() failure path.
-        * Ignore this case since the task hasn't ran yet, this avoids
-        * trying to poke a half freed task state from generic code.
-        */
-       if (!(task->flags & PF_EXITING))
-               return;
-
        sched_move_task(task);
 }