.func = nohz_full_kick_work_func,
};
+/*
+ * Kick this CPU if it's full dynticks in order to force it to
+ * re-evaluate its dependency on the tick and restart it if necessary.
+ * This kick, unlike tick_nohz_full_kick_cpu() and tick_nohz_full_kick_all(),
+ * is NMI safe.
+ */
+void tick_nohz_full_kick(void)
+{
+ if (!tick_nohz_full_cpu(smp_processor_id()))
+ return;
+
+ irq_work_queue(&__get_cpu_var(nohz_full_kick_work));
+}
+
/*
* Kick the CPU if it's full dynticks in order to force it to
* re-evaluate its dependency on the tick and restart it if necessary.
/* Parse the boot-time nohz CPU list from the kernel parameters. */
static int __init tick_nohz_full_setup(char *str)
{
- int cpu;
-
alloc_bootmem_cpumask_var(&tick_nohz_full_mask);
- alloc_bootmem_cpumask_var(&housekeeping_mask);
if (cpulist_parse(str, tick_nohz_full_mask) < 0) {
pr_warning("NOHZ: Incorrect nohz_full cpumask\n");
+ free_bootmem_cpumask_var(tick_nohz_full_mask);
return 1;
}
-
- cpu = smp_processor_id();
- if (cpumask_test_cpu(cpu, tick_nohz_full_mask)) {
- pr_warning("NO_HZ: Clearing %d from nohz_full range for timekeeping\n", cpu);
- cpumask_clear_cpu(cpu, tick_nohz_full_mask);
- }
- cpumask_andnot(housekeeping_mask,
- cpu_possible_mask, tick_nohz_full_mask);
tick_nohz_full_running = true;
return 1;
#ifdef CONFIG_NO_HZ_FULL_ALL
if (!alloc_cpumask_var(&tick_nohz_full_mask, GFP_KERNEL)) {
- pr_err("NO_HZ: Can't allocate full dynticks cpumask\n");
- return err;
- }
- if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
- pr_err("NO_HZ: Can't allocate not-full dynticks cpumask\n");
+ WARN(1, "NO_HZ: Can't allocate full dynticks cpumask\n");
return err;
}
err = 0;
cpumask_setall(tick_nohz_full_mask);
- cpumask_clear_cpu(smp_processor_id(), tick_nohz_full_mask);
- cpumask_clear(housekeeping_mask);
- cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
tick_nohz_full_running = true;
#endif
return err;
return;
}
+ if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
+ WARN(1, "NO_HZ: Can't allocate not-full dynticks cpumask\n");
+ cpumask_clear(tick_nohz_full_mask);
+ tick_nohz_full_running = false;
+ return;
+ }
+
+ /*
+ * Full dynticks uses irq work to drive the tick rescheduling on safe
+ * locking contexts. But then we need irq work to raise its own
+ * interrupts to avoid circular dependency on the tick
+ */
+ if (!arch_irq_work_has_interrupt()) {
+ pr_warning("NO_HZ: Can't run full dynticks because arch doesn't "
+ "support irq work self-IPIs\n");
+ cpumask_clear(tick_nohz_full_mask);
+ cpumask_copy(housekeeping_mask, cpu_possible_mask);
+ tick_nohz_full_running = false;
+ return;
+ }
+
+ cpu = smp_processor_id();
+
+ if (cpumask_test_cpu(cpu, tick_nohz_full_mask)) {
+ pr_warning("NO_HZ: Clearing %d from nohz_full range for timekeeping\n", cpu);
+ cpumask_clear_cpu(cpu, tick_nohz_full_mask);
+ }
+
+ cpumask_andnot(housekeeping_mask,
+ cpu_possible_mask, tick_nohz_full_mask);
+
for_each_cpu(cpu, tick_nohz_full_mask)
context_tracking_cpu_set(cpu);