sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8b51b2d..f895fdd 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1764,7 +1764,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
         *              Manfred Spraul <manfred@colorfullife.com>
         */
        prev_state = prev->state;
-       account_switch_vtime(prev);
+       vtime_task_switch(prev);
        finish_arch_switch(prev);
        perf_event_task_sched_in(prev, current);
        finish_lock_switch(rq, prev);
@@ -1887,6 +1887,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
 #endif
 
        /* Here we just switch the register state and the stack. */
+       rcu_switch(prev, next);
        switch_to(prev, next, prev);
 
        barrier();
@@ -2910,6 +2911,21 @@ asmlinkage void __sched schedule(void)
 }
 EXPORT_SYMBOL(schedule);
 
+#ifdef CONFIG_RCU_USER_QS
+asmlinkage void __sched schedule_user(void)
+{
+       /*
+        * If we come here after a random call to set_need_resched(),
+        * or we have been woken up remotely but the IPI has not yet arrived,
+        * we haven't yet exited the RCU idle mode. Do it here manually until
+        * we find a better solution.
+        */
+       rcu_user_exit();
+       schedule();
+       rcu_user_enter();
+}
+#endif
+
 /**
  * schedule_preempt_disabled - called with preemption disabled
  *
@@ -3011,6 +3027,7 @@ asmlinkage void __sched preempt_schedule_irq(void)
        /* Catch callers which need to be fixed */
        BUG_ON(ti->preempt_count || !irqs_disabled());
 
+       rcu_user_exit();
        do {
                add_preempt_count(PREEMPT_ACTIVE);
                local_irq_enable();
@@ -5048,7 +5065,9 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
                migrate_tasks(cpu);
                BUG_ON(rq->nr_running != 1); /* the migration thread */
                raw_spin_unlock_irqrestore(&rq->lock, flags);
+               break;
 
+       case CPU_DEAD:
                calc_load_migrate(rq);
                break;
 #endif
@@ -5458,11 +5477,6 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu)
  * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
  * allows us to avoid some pointer chasing select_idle_sibling().
  *
- * Iterate domains and sched_groups downward, assigning CPUs to be
- * select_idle_sibling() hw buddy.  Cross-wiring hw makes bouncing
- * due to random perturbation self canceling, ie sw buddies pull
- * their counterpart to their CPU's hw counterpart.
- *
  * Also keep a unique ID per domain (we use the first cpu number in
  * the cpumask of the domain), this allows us to quickly tell if
  * two cpus are in the same cache domain, see cpus_share_cache().
@@ -5476,40 +5490,8 @@ static void update_top_cache_domain(int cpu)
        int id = cpu;
 
        sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
-       if (sd) {
-               struct sched_domain *tmp = sd;
-               struct sched_group *sg, *prev;
-               bool right;
-
-               /*
-                * Traverse to first CPU in group, and count hops
-                * to cpu from there, switching direction on each
-                * hop, never ever pointing the last CPU rightward.
-                */
-               do {
-                       id = cpumask_first(sched_domain_span(tmp));
-                       prev = sg = tmp->groups;
-                       right = 1;
-
-                       while (cpumask_first(sched_group_cpus(sg)) != id)
-                               sg = sg->next;
-
-                       while (!cpumask_test_cpu(cpu, sched_group_cpus(sg))) {
-                               prev = sg;
-                               sg = sg->next;
-                               right = !right;
-                       }
-
-                       /* A CPU went down, never point back to domain start. */
-                       if (right && cpumask_first(sched_group_cpus(sg->next)) == id)
-                               right = false;
-
-                       sg = right ? sg->next : prev;
-                       tmp->idle_buddy = cpumask_first(sched_group_cpus(sg));
-               } while ((tmp = tmp->child));
-
+       if (sd)
                id = cpumask_first(sched_domain_span(sd));
-       }
 
        rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
        per_cpu(sd_llc_id, cpu) = id;
@@ -6140,6 +6122,17 @@ static void sched_init_numa(void)
         * numbers.
         */
 
+       /*
+        * Here, we should temporarily reset sched_domains_numa_levels to 0.
+        * If it fails to allocate memory for array sched_domains_numa_masks[][],
+        * the array will contain less then 'level' members. This could be
+        * dangerous when we use it to iterate array sched_domains_numa_masks[][]
+        * in other functions.
+        *
+        * We reset it to 'level' at the end of this function.
+        */
+       sched_domains_numa_levels = 0;
+
        sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
        if (!sched_domains_numa_masks)
                return;
@@ -6194,6 +6187,8 @@ static void sched_init_numa(void)
        }
 
        sched_domain_topology = tl;
+
+       sched_domains_numa_levels = level;
 }
 #else
 static inline void sched_init_numa(void)