sched: convert nohz struct to cpumask_var_t.
Impact: (future) size reduction for large NR_CPUS.
Dynamically allocating cpumasks (when CONFIG_CPUMASK_OFFSTACK) saves
space for small nr_cpu_ids but big CONFIG_NR_CPUS. cpumask_var_t
is just a struct cpumask for !CONFIG_CPUMASK_OFFSTACK.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 93309c3..2f8ea99 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3758,10 +3758,9 @@
#ifdef CONFIG_NO_HZ
static struct {
atomic_t load_balancer;
- cpumask_t cpu_mask;
+ cpumask_var_t cpu_mask;
} nohz ____cacheline_aligned = {
.load_balancer = ATOMIC_INIT(-1),
- .cpu_mask = CPU_MASK_NONE,
};
/*
@@ -3789,7 +3788,7 @@
int cpu = smp_processor_id();
if (stop_tick) {
- cpu_set(cpu, nohz.cpu_mask);
+ cpumask_set_cpu(cpu, nohz.cpu_mask);
cpu_rq(cpu)->in_nohz_recently = 1;
/*
@@ -3803,7 +3802,7 @@
}
/* time for ilb owner also to sleep */
- if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
+ if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
if (atomic_read(&nohz.load_balancer) == cpu)
atomic_set(&nohz.load_balancer, -1);
return 0;
@@ -3816,10 +3815,10 @@
} else if (atomic_read(&nohz.load_balancer) == cpu)
return 1;
} else {
- if (!cpu_isset(cpu, nohz.cpu_mask))
+ if (!cpumask_test_cpu(cpu, nohz.cpu_mask))
return 0;
- cpu_clear(cpu, nohz.cpu_mask);
+ cpumask_clear_cpu(cpu, nohz.cpu_mask);
if (atomic_read(&nohz.load_balancer) == cpu)
if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
@@ -3930,12 +3929,13 @@
*/
if (this_rq->idle_at_tick &&
atomic_read(&nohz.load_balancer) == this_cpu) {
- cpumask_t cpus = nohz.cpu_mask;
struct rq *rq;
int balance_cpu;
- cpu_clear(this_cpu, cpus);
- for_each_cpu(balance_cpu, &cpus) {
+ for_each_cpu(balance_cpu, nohz.cpu_mask) {
+ if (balance_cpu == this_cpu)
+ continue;
+
/*
* If this cpu gets work to do, stop the load balancing
* work being done for other cpus. Next load
@@ -3973,7 +3973,7 @@
rq->in_nohz_recently = 0;
if (atomic_read(&nohz.load_balancer) == cpu) {
- cpu_clear(cpu, nohz.cpu_mask);
+ cpumask_clear_cpu(cpu, nohz.cpu_mask);
atomic_set(&nohz.load_balancer, -1);
}
@@ -3986,7 +3986,7 @@
* TBD: Traverse the sched domains and nominate
* the nearest cpu in the nohz.cpu_mask.
*/
- int ilb = first_cpu(nohz.cpu_mask);
+ int ilb = cpumask_first(nohz.cpu_mask);
if (ilb < nr_cpu_ids)
resched_cpu(ilb);
@@ -3998,7 +3998,7 @@
* cpus with ticks stopped, is it time for that to stop?
*/
if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
- cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
+ cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
resched_cpu(cpu);
return;
}
@@ -4008,7 +4008,7 @@
* someone else, then no need raise the SCHED_SOFTIRQ
*/
if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
- cpu_isset(cpu, nohz.cpu_mask))
+ cpumask_test_cpu(cpu, nohz.cpu_mask))
return;
#endif
if (time_after_eq(jiffies, rq->next_balance))
@@ -8309,6 +8309,9 @@
/* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
alloc_bootmem_cpumask_var(&nohz_cpu_mask);
+#ifdef CONFIG_NO_HZ
+ alloc_bootmem_cpumask_var(&nohz.cpu_mask);
+#endif
scheduler_running = 1;
}