@@ -1549,6 +1549,7 @@ static int find_lowest_rq(struct task_struct *task)
struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
int this_cpu = smp_processor_id();
int cpu = task_cpu(task);
+ int cachehot_cpu = nr_cpu_ids;
/* Make sure the mask is initialized first */
if (unlikely(!lowest_mask))
@@ -1581,7 +1582,7 @@ static int find_lowest_rq(struct task_struct *task)
rcu_read_lock();
for_each_domain(cpu, sd) {
if (sd->flags & SD_WAKE_AFFINE) {
- int best_cpu;
+ int wakeaffine_cpu;
/*
* "this_cpu" is cheaper to preempt than a
@@ -1593,16 +1594,25 @@ static int find_lowest_rq(struct task_struct *task)
return this_cpu;
}
- best_cpu = cpumask_first_and(lowest_mask,
+ wakeaffine_cpu = cpumask_first_and(lowest_mask,
sched_domain_span(sd));
- if (best_cpu < nr_cpu_ids) {
+ if (wakeaffine_cpu < nr_cpu_ids) {
rcu_read_unlock();
- return best_cpu;
+ return wakeaffine_cpu;
}
+ } else {
+ /* affine domain outweighs lower level non-affine domain? */
+ if (cachehot_cpu >= nr_cpu_ids)
+ cachehot_cpu = cpumask_first_and(lowest_mask,
+ sched_domain_span(sd));
}
}
rcu_read_unlock();
+ /* most likely cache-hot */
+ if (cachehot_cpu < nr_cpu_ids)
+ return cachehot_cpu;
+
/*
* And finally, if there were no matches within the domains
* just give the caller *something* to work with from the compatible
Add the case for iteration of sched_domains without SD_WAKE_AFFINE flags to select a cpu, this flag may be unset through proc by users. Signed-off-by: pang.xunlei <pang.xunlei@linaro.org> --- kernel/sched/rt.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)