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Code Issues Releases Wiki Activity

cpumask: reduce stack usage in find_lowest_rq 

Impact: reduce stack usage, cleanup

Use a cpumask_var_t in find_lowest_rq() and clean up other old
cpumask_t calls.

Signed-off-by: Mike Travis <travis@sgi.com>
This commit is contained in:
Mike Travis 2009-01-10 21:58:11 -08:00 committed by Ingo Molnar
parent c90e785be2
commit d38b223c86
1 changed files with 22 additions and 14 deletions
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36
kernel/sched_rt.c
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@ -960,16 +960,17 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask)
static inline int pick_optimal_cpu(int this_cpu,
const struct cpumask *mask)
{
int first;
/* "this_cpu" is cheaper to preempt than a remote processor */
if ((this_cpu != -1) && cpu_isset(this_cpu, *mask))
if ((this_cpu != -1) && cpumask_test_cpu(this_cpu, mask))
return this_cpu;
first = first_cpu(*mask);
if (first != NR_CPUS)
first = cpumask_first(mask);
if (first < nr_cpu_ids)
return first;
return -1;
@ -981,6 +982,7 @@ static int find_lowest_rq(struct task_struct *task)
struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
int this_cpu = smp_processor_id();
int cpu = task_cpu(task);
cpumask_var_t domain_mask;
if (task->rt.nr_cpus_allowed == 1)
return -1; /* No other targets possible */
@ -1013,19 +1015,25 @@ static int find_lowest_rq(struct task_struct *task)
if (this_cpu == cpu)
this_cpu = -1; /* Skip this_cpu opt if the same */
for_each_domain(cpu, sd) {
if (sd->flags & SD_WAKE_AFFINE) {
cpumask_t domain_mask;
int best_cpu;
if (alloc_cpumask_var(&domain_mask, GFP_ATOMIC)) {
for_each_domain(cpu, sd) {
if (sd->flags & SD_WAKE_AFFINE) {
int best_cpu;
cpumask_and(&domain_mask, sched_domain_span(sd),
lowest_mask);
cpumask_and(domain_mask,
sched_domain_span(sd),
lowest_mask);
best_cpu = pick_optimal_cpu(this_cpu,
&domain_mask);
if (best_cpu != -1)
return best_cpu;
best_cpu = pick_optimal_cpu(this_cpu,
domain_mask);
if (best_cpu != -1) {
free_cpumask_var(domain_mask);
return best_cpu;
}
}
}
free_cpumask_var(domain_mask);
}
/*