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Commit 68e74568 authored by Rusty Russell's avatar Rusty Russell Committed by Ingo Molnar
Browse files

sched: convert struct cpupri_vec cpumask_var_t. 



Impact: stack usage reduction, (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.

The fact cpupro_init is called both before and after the slab is
available makes for an ugly parameter unfortunately.

We also use cpumask_any_and to get rid of a temporary in cpupri_find.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4212823f

kernel/sched.c

+7 −2
Original line number Diff line number Diff line
@@ -6792,6 +6792,8 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) 


static void free_rootdomain(struct root_domain *rd)

{

	cpupri_cleanup(&rd->cpupri);



	free_cpumask_var(rd->rto_mask);

	free_cpumask_var(rd->online);

	free_cpumask_var(rd->span);
@@ -6834,7 +6836,7 @@ static int init_rootdomain(struct root_domain *rd, bool bootmem) 
		alloc_bootmem_cpumask_var(&def_root_domain.span);

		alloc_bootmem_cpumask_var(&def_root_domain.online);

		alloc_bootmem_cpumask_var(&def_root_domain.rto_mask);

		cpupri_init(&rd->cpupri);

		cpupri_init(&rd->cpupri, true);

		return 0;

	}
@@ -6845,9 +6847,12 @@ static int init_rootdomain(struct root_domain *rd, bool bootmem) 
	if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))

		goto free_online;



	cpupri_init(&rd->cpupri);

	if (cpupri_init(&rd->cpupri, false) != 0)

		goto free_rto_mask;

	return 0;



free_rto_mask:

	free_cpumask_var(rd->rto_mask);

free_online:

	free_cpumask_var(rd->online);

free_span:

kernel/sched_cpupri.c

+28 −11
Original line number Diff line number Diff line
@@ -67,24 +67,21 @@ static int convert_prio(int prio) 
 * Returns: (int)bool - CPUs were found

 */

int cpupri_find(struct cpupri *cp, struct task_struct *p,

		cpumask_t *lowest_mask)

		struct cpumask *lowest_mask)

{

	int                  idx      = 0;

	int                  task_pri = convert_prio(p->prio);



	for_each_cpupri_active(cp->pri_active, idx) {

		struct cpupri_vec *vec  = &cp->pri_to_cpu[idx];

		cpumask_t mask;



		if (idx >= task_pri)

			break;



		cpus_and(mask, p->cpus_allowed, vec->mask);



		if (cpus_empty(mask))

		if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)

			continue;



		*lowest_mask = mask;

		cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);

		return 1;

	}
@@ -126,7 +123,7 @@ void cpupri_set(struct cpupri *cp, int cpu, int newpri) 
		vec->count--;

		if (!vec->count)

			clear_bit(oldpri, cp->pri_active);

		cpu_clear(cpu, vec->mask);

		cpumask_clear_cpu(cpu, vec->mask);



		spin_unlock_irqrestore(&vec->lock, flags);

	}
@@ -136,7 +133,7 @@ void cpupri_set(struct cpupri *cp, int cpu, int newpri) 


		spin_lock_irqsave(&vec->lock, flags);



		cpu_set(cpu, vec->mask);

		cpumask_set_cpu(cpu, vec->mask);

		vec->count++;

		if (vec->count == 1)

			set_bit(newpri, cp->pri_active);
@@ -150,10 +147,11 @@ void cpupri_set(struct cpupri *cp, int cpu, int newpri) 
/**

 * cpupri_init - initialize the cpupri structure

 * @cp: The cpupri context

 * @bootmem: true if allocations need to use bootmem

 *

 * Returns: (void)

 * Returns: -ENOMEM if memory fails.

 */

void cpupri_init(struct cpupri *cp)

int cpupri_init(struct cpupri *cp, bool bootmem)

{

	int i;
@@ -164,11 +162,30 @@ void cpupri_init(struct cpupri *cp) 


		spin_lock_init(&vec->lock);

		vec->count = 0;

		cpus_clear(vec->mask);

		if (bootmem)

			alloc_bootmem_cpumask_var(&vec->mask);

		else if (!alloc_cpumask_var(&vec->mask, GFP_KERNEL))

			goto cleanup;

	}



	for_each_possible_cpu(i)

		cp->cpu_to_pri[i] = CPUPRI_INVALID;

	return 0;



cleanup:

	for (i--; i >= 0; i--)

		free_cpumask_var(cp->pri_to_cpu[i].mask);

	return -ENOMEM;

}



/**

 * cpupri_cleanup - clean up the cpupri structure

 * @cp: The cpupri context

 */

void cpupri_cleanup(struct cpupri *cp)

{

	int i;



	for (i = 0; i < CPUPRI_NR_PRIORITIES; i++)

		free_cpumask_var(cp->pri_to_cpu[i].mask);

}

kernel/sched_cpupri.h

+3 −2
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ 
struct cpupri_vec {

	spinlock_t lock;

	int        count;

	cpumask_t  mask;

	cpumask_var_t mask;

};



struct cpupri {
@@ -27,7 +27,8 @@ struct cpupri { 
int  cpupri_find(struct cpupri *cp,

		 struct task_struct *p, cpumask_t *lowest_mask);

void cpupri_set(struct cpupri *cp, int cpu, int pri);

void cpupri_init(struct cpupri *cp);

int cpupri_init(struct cpupri *cp, bool bootmem);

void cpupri_cleanup(struct cpupri *cp);

#else

#define cpupri_set(cp, cpu, pri) do { } while (0)

#define cpupri_init() do { } while (0)