nohz: Consolidate nohz full init code

The supports for CONFIG_NO_HZ_FULL_ALL=y and the nohz_full= kernel
parameter both have their own way to do the same thing: allocate
full dynticks cpumasks, fill them and initialize some state variables.

Lets consolidate that all in the same place.

While at it, convert some regular printk message to warnings when
fundamental allocations fail.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index f654a8a..eb4af01 100644 (file)
--- 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 +358,23 @@ 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;
+       }
+
+       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);