summaryrefslogtreecommitdiff
path: root/kernel/sched/core.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r--kernel/sched/core.c154
1 files changed, 77 insertions, 77 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5e10aaeebfcc..e9866f86f304 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7,6 +7,9 @@
*/
#include "sched.h"
+#include <linux/kthread.h>
+#include <linux/nospec.h>
+
#include <asm/switch_to.h>
#include <asm/tlb.h>
@@ -878,6 +881,33 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
}
#ifdef CONFIG_SMP
+
+static inline bool is_per_cpu_kthread(struct task_struct *p)
+{
+ if (!(p->flags & PF_KTHREAD))
+ return false;
+
+ if (p->nr_cpus_allowed != 1)
+ return false;
+
+ return true;
+}
+
+/*
+ * Per-CPU kthreads are allowed to run on !actie && online CPUs, see
+ * __set_cpus_allowed_ptr() and select_fallback_rq().
+ */
+static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
+{
+ if (!cpumask_test_cpu(cpu, &p->cpus_allowed))
+ return false;
+
+ if (is_per_cpu_kthread(p))
+ return cpu_online(cpu);
+
+ return cpu_active(cpu);
+}
+
/*
* This is how migration works:
*
@@ -935,16 +965,8 @@ struct migration_arg {
static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
struct task_struct *p, int dest_cpu)
{
- if (p->flags & PF_KTHREAD) {
- if (unlikely(!cpu_online(dest_cpu)))
- return rq;
- } else {
- if (unlikely(!cpu_active(dest_cpu)))
- return rq;
- }
-
/* Affinity changed (again). */
- if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
+ if (!is_cpu_allowed(p, dest_cpu))
return rq;
update_rq_clock(rq);
@@ -1473,10 +1495,9 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
for (;;) {
/* Any allowed, online CPU? */
for_each_cpu(dest_cpu, &p->cpus_allowed) {
- if (!(p->flags & PF_KTHREAD) && !cpu_active(dest_cpu))
- continue;
- if (!cpu_online(dest_cpu))
+ if (!is_cpu_allowed(p, dest_cpu))
continue;
+
goto out;
}
@@ -1539,8 +1560,7 @@ int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
* [ this allows ->select_task() to simply return task_cpu(p) and
* not worry about this generic constraint ]
*/
- if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
- !cpu_online(cpu)))
+ if (unlikely(!is_cpu_allowed(p, cpu)))
cpu = select_fallback_rq(task_cpu(p), p);
return cpu;
@@ -2174,27 +2194,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
INIT_HLIST_HEAD(&p->preempt_notifiers);
#endif
-#ifdef CONFIG_NUMA_BALANCING
- if (p->mm && atomic_read(&p->mm->mm_users) == 1) {
- p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
- p->mm->numa_scan_seq = 0;
- }
-
- if (clone_flags & CLONE_VM)
- p->numa_preferred_nid = current->numa_preferred_nid;
- else
- p->numa_preferred_nid = -1;
-
- p->node_stamp = 0ULL;
- p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;
- p->numa_scan_period = sysctl_numa_balancing_scan_delay;
- p->numa_work.next = &p->numa_work;
- p->numa_faults = NULL;
- p->last_task_numa_placement = 0;
- p->last_sum_exec_runtime = 0;
-
- p->numa_group = NULL;
-#endif /* CONFIG_NUMA_BALANCING */
+ init_numa_balancing(clone_flags, p);
}
DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
@@ -2718,20 +2718,28 @@ static struct rq *finish_task_switch(struct task_struct *prev)
membarrier_mm_sync_core_before_usermode(mm);
mmdrop(mm);
}
- if (unlikely(prev_state == TASK_DEAD)) {
- if (prev->sched_class->task_dead)
- prev->sched_class->task_dead(prev);
+ if (unlikely(prev_state & (TASK_DEAD|TASK_PARKED))) {
+ switch (prev_state) {
+ case TASK_DEAD:
+ if (prev->sched_class->task_dead)
+ prev->sched_class->task_dead(prev);
- /*
- * Remove function-return probe instances associated with this
- * task and put them back on the free list.
- */
- kprobe_flush_task(prev);
+ /*
+ * Remove function-return probe instances associated with this
+ * task and put them back on the free list.
+ */
+ kprobe_flush_task(prev);
- /* Task is done with its stack. */
- put_task_stack(prev);
+ /* Task is done with its stack. */
+ put_task_stack(prev);
- put_task_struct(prev);
+ put_task_struct(prev);
+ break;
+
+ case TASK_PARKED:
+ kthread_park_complete(prev);
+ break;
+ }
}
tick_nohz_task_switch();
@@ -3498,23 +3506,8 @@ static void __sched notrace __schedule(bool preempt)
void __noreturn do_task_dead(void)
{
- /*
- * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
- * when the following two conditions become true.
- * - There is race condition of mmap_sem (It is acquired by
- * exit_mm()), and
- * - SMI occurs before setting TASK_RUNINNG.
- * (or hypervisor of virtual machine switches to other guest)
- * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
- *
- * To avoid it, we have to wait for releasing tsk->pi_lock which
- * is held by try_to_wake_up()
- */
- raw_spin_lock_irq(&current->pi_lock);
- raw_spin_unlock_irq(&current->pi_lock);
-
/* Causes final put_task_struct in finish_task_switch(): */
- __set_current_state(TASK_DEAD);
+ set_special_state(TASK_DEAD);
/* Tell freezer to ignore us: */
current->flags |= PF_NOFREEZE;
@@ -4037,6 +4030,23 @@ int idle_cpu(int cpu)
}
/**
+ * available_idle_cpu - is a given CPU idle for enqueuing work.
+ * @cpu: the CPU in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int available_idle_cpu(int cpu)
+{
+ if (!idle_cpu(cpu))
+ return 0;
+
+ if (vcpu_is_preempted(cpu))
+ return 0;
+
+ return 1;
+}
+
+/**
* idle_task - return the idle task for a given CPU.
* @cpu: the processor in question.
*
@@ -5012,20 +5022,6 @@ int __cond_resched_lock(spinlock_t *lock)
}
EXPORT_SYMBOL(__cond_resched_lock);
-int __sched __cond_resched_softirq(void)
-{
- BUG_ON(!in_softirq());
-
- if (should_resched(SOFTIRQ_DISABLE_OFFSET)) {
- local_bh_enable();
- preempt_schedule_common();
- local_bh_disable();
- return 1;
- }
- return 0;
-}
-EXPORT_SYMBOL(__cond_resched_softirq);
-
/**
* yield - yield the current processor to other threads.
*
@@ -6928,11 +6924,15 @@ static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
struct cftype *cft, s64 nice)
{
unsigned long weight;
+ int idx;
if (nice < MIN_NICE || nice > MAX_NICE)
return -ERANGE;
- weight = sched_prio_to_weight[NICE_TO_PRIO(nice) - MAX_RT_PRIO];
+ idx = NICE_TO_PRIO(nice) - MAX_RT_PRIO;
+ idx = array_index_nospec(idx, 40);
+ weight = sched_prio_to_weight[idx];
+
return sched_group_set_shares(css_tg(css), scale_load(weight));
}
#endif
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-14 19:10:21 +0300