1 files changed, 33 insertions, 19 deletions

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index f654a8a..5a9ff24 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -295,22 +295,12 @@ out:
 /* 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;
@@ -349,18 +339,11 @@ static int tick_nohz_init_all(void)
 
 #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;
@@ -375,6 +358,37 @@ void __init tick_nohz_init(void)
 			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);