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sched: convert struct cpupri_vec cpumask_var_t.

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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: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Rusty Russell 2008-11-25 02:35:13 +10:30 • committed by Ingo Molnar
commit 68e74568fb
3 changed files with 38 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

9
kernel/sched.c
View file

@ -6792,6 +6792,8 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
static void free_rootdomain(struct root_domain *rd) static void free_rootdomain(struct root_domain *rd)
{ {
cpupri_cleanup(&rd->cpupri);
free_cpumask_var(rd->rto_mask); free_cpumask_var(rd->rto_mask);
free_cpumask_var(rd->online); free_cpumask_var(rd->online);
free_cpumask_var(rd->span); 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.span);
alloc_bootmem_cpumask_var(&def_root_domain.online); alloc_bootmem_cpumask_var(&def_root_domain.online);
alloc_bootmem_cpumask_var(&def_root_domain.rto_mask); alloc_bootmem_cpumask_var(&def_root_domain.rto_mask);
cpupri_init(&rd->cpupri); cpupri_init(&rd->cpupri, true);
return 0; 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)) if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
goto free_online; goto free_online;
cpupri_init(&rd->cpupri); if (cpupri_init(&rd->cpupri, false) != 0)
goto free_rto_mask;
return 0; return 0;
free_rto_mask:
free_cpumask_var(rd->rto_mask);
free_online: free_online:
free_cpumask_var(rd->online); free_cpumask_var(rd->online);
free_span: free_span:

39
kernel/sched_cpupri.c
View file

@ -67,24 +67,21 @@ static int convert_prio(int prio)
* Returns: (int)bool - CPUs were found * Returns: (int)bool - CPUs were found
*/ */
int cpupri_find(struct cpupri *cp, struct task_struct *p, int cpupri_find(struct cpupri *cp, struct task_struct *p,
cpumask_t *lowest_mask) struct cpumask *lowest_mask)
{ {
int idx = 0; int idx = 0;
int task_pri = convert_prio(p->prio); int task_pri = convert_prio(p->prio);
for_each_cpupri_active(cp->pri_active, idx) { for_each_cpupri_active(cp->pri_active, idx) {
struct cpupri_vec *vec = &cp->pri_to_cpu[idx]; struct cpupri_vec *vec = &cp->pri_to_cpu[idx];
cpumask_t mask;
if (idx >= task_pri) if (idx >= task_pri)
break; break;
cpus_and(mask, p->cpus_allowed, vec->mask); if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)
if (cpus_empty(mask))
continue; continue;
*lowest_mask = mask; cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);
return 1; return 1;
} }
@ -126,7 +123,7 @@ void cpupri_set(struct cpupri *cp, int cpu, int newpri)
vec->count--; vec->count--;
if (!vec->count) if (!vec->count)
clear_bit(oldpri, cp->pri_active); clear_bit(oldpri, cp->pri_active);
cpu_clear(cpu, vec->mask); cpumask_clear_cpu(cpu, vec->mask);
spin_unlock_irqrestore(&vec->lock, flags); 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); spin_lock_irqsave(&vec->lock, flags);
cpu_set(cpu, vec->mask); cpumask_set_cpu(cpu, vec->mask);
vec->count++; vec->count++;
if (vec->count == 1) if (vec->count == 1)
set_bit(newpri, cp->pri_active); 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 * cpupri_init - initialize the cpupri structure
* @cp: The cpupri context * @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; int i;
@ -164,11 +162,30 @@ void cpupri_init(struct cpupri *cp)
spin_lock_init(&vec->lock); spin_lock_init(&vec->lock);
vec->count = 0; 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) for_each_possible_cpu(i)
cp->cpu_to_pri[i] = CPUPRI_INVALID; 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);
}

5
kernel/sched_cpupri.h
View file

@ -14,7 +14,7 @@
struct cpupri_vec { struct cpupri_vec {
spinlock_t lock; spinlock_t lock;
int count; int count;
cpumask_t mask; cpumask_var_t mask;
}; };
struct cpupri { struct cpupri {
@ -27,7 +27,8 @@ struct cpupri {
int cpupri_find(struct cpupri *cp, int cpupri_find(struct cpupri *cp,
struct task_struct *p, cpumask_t *lowest_mask); struct task_struct *p, cpumask_t *lowest_mask);
void cpupri_set(struct cpupri *cp, int cpu, int pri); 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 #else
#define cpupri_set(cp, cpu, pri) do { } while (0) #define cpupri_set(cp, cpu, pri) do { } while (0)
#define cpupri_init() do { } while (0) #define cpupri_init() do { } while (0)