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Commit 4212823f authored by Rusty Russell's avatar Rusty Russell Committed by Ingo Molnar
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sched: convert falback_doms 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: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent dcc30a35

kernel/sched.c

+8 −6
Original line number Diff line number Diff line
@@ -7697,10 +7697,10 @@ static struct sched_domain_attr *dattr_cur; 


/*

 * Special case: If a kmalloc of a doms_cur partition (array of

 * cpumask_t) fails, then fallback to a single sched domain,

 * as determined by the single cpumask_t fallback_doms.

 * cpumask) fails, then fallback to a single sched domain,

 * as determined by the single cpumask fallback_doms.

 */

static cpumask_t fallback_doms;

static cpumask_var_t fallback_doms;



void __attribute__((weak)) arch_update_cpu_topology(void)

{
@@ -7719,7 +7719,7 @@ static int arch_init_sched_domains(const cpumask_t *cpu_map) 
	ndoms_cur = 1;

	doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);

	if (!doms_cur)

		doms_cur = &fallback_doms;

		doms_cur = fallback_doms;

	cpumask_andnot(doms_cur, cpu_map, cpu_isolated_map);

	dattr_cur = NULL;

	err = build_sched_domains(doms_cur);
@@ -7818,7 +7818,7 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new, 


	if (doms_new == NULL) {

		ndoms_cur = 0;

		doms_new = &fallback_doms;

		doms_new = fallback_doms;

		cpumask_andnot(&doms_new[0], cpu_online_mask, cpu_isolated_map);

		WARN_ON_ONCE(dattr_new);

	}
@@ -7838,7 +7838,7 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new, 
	}



	/* Remember the new sched domains */

	if (doms_cur != &fallback_doms)

	if (doms_cur != fallback_doms)

		kfree(doms_cur);

	kfree(dattr_cur);	/* kfree(NULL) is safe */

	doms_cur = doms_new;
@@ -8011,6 +8011,8 @@ void __init sched_init_smp(void) 
		BUG();

	sched_init_granularity();

	free_cpumask_var(non_isolated_cpus);



	alloc_cpumask_var(&fallback_doms, GFP_KERNEL);

}

#else

void __init sched_init_smp(void)