Messages in this thread | | | Date | Tue, 28 Mar 2017 09:04:29 +0900 | From | Byungchul Park <> | Subject | Re: [PATCH v3 1/3] sched/deadline: Make find_later_rq() choose a closer cpu in topology |
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On Mon, Mar 27, 2017 at 03:33:43PM +0100, Juri Lelli wrote: > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > index a2ce590..49c93b9 100644 > > --- a/kernel/sched/deadline.c > > +++ b/kernel/sched/deadline.c > > @@ -1324,7 +1324,7 @@ static int find_later_rq(struct task_struct *task) > > struct sched_domain *sd; > > struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl); > > int this_cpu = smp_processor_id(); > > - int best_cpu, cpu = task_cpu(task); > > + int cpu = task_cpu(task); > > > > /* Make sure the mask is initialized first */ > > if (unlikely(!later_mask)) > > @@ -1337,17 +1337,14 @@ static int find_later_rq(struct task_struct *task) > > * We have to consider system topology and task affinity > > * first, then we can look for a suitable cpu. > > */ > > - best_cpu = cpudl_find(&task_rq(task)->rd->cpudl, > > - task, later_mask); > > - if (best_cpu == -1) > > + if (cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask) == -1) > > It seems that with this we loose the last user of the current return > value of cpudl_find() (heap maximum). I guess we want to change the > return value to be (int)bool, as in rt, so that we can simplify this and > the conditions in check_preempt_equal_dl.
Hi Juri,
Actually I changed the return value to be bool, but didn't include the patch since it looks not that valuable. But I will add it if you also think so. ;)
> > > return -1; > > > > /* > > - * If we are here, some target has been found, > > - * the most suitable of which is cached in best_cpu. > > - * This is, among the runqueues where the current tasks > > - * have later deadlines than the task's one, the rq > > - * with the latest possible one. > > + * If we are here, some targets have been found, including > > + * the most suitable which is, among the runqueues where the > > + * current tasks have later deadlines than the task's one, the > > + * rq with the latest possible one. > > * > > * Now we check how well this matches with task's > > * affinity and system topology. > > @@ -1367,6 +1364,7 @@ static int find_later_rq(struct task_struct *task) > > rcu_read_lock(); > > for_each_domain(cpu, sd) { > > if (sd->flags & SD_WAKE_AFFINE) { > > + int closest_cpu; > > Can we still call this best_cpu, so that we are aligned with rt?
OK. I will rename it to best_cpu.
Thanks, Byungchul
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