On Wed, 19 Nov 2014 23:46:22 +0800 "pang.xunlei" <[email protected]> wrote:
> cpudl_find() is not a good place to select the best cpu, so leave > this role to its call site, currently it is find_later_rq() where > we can do the election of the best cpu according to sd topology. > > Signed-off-by: pang.xunlei <[email protected]> > --- > kernel/sched/cpudeadline.c | 15 +++++---------- > kernel/sched/deadline.c | 17 ++++++----------- > 2 files changed, 11 insertions(+), 21 deletions(-) > > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c > index 3047846..41d3578 100644 > --- a/kernel/sched/cpudeadline.c > +++ b/kernel/sched/cpudeadline.c > @@ -100,29 +100,24 @@ static inline int cpudl_maximum(struct cpudl *cp) > * @later_mask: a mask to fill in with the selected CPUs (not NULL) > * @set_flag: indicate if later_mask should be set > * > - * Returns: int - best CPU (heap maximum if suitable) > + * Return: (int)bool - CPUs were found > */ > int cpudl_find(struct cpudl *cp, struct task_struct *p, > struct cpumask *later_mask, int set_flag) > { > - int best_cpu = -1; > const struct sched_dl_entity *dl_se = &p->dl; > > cpumask_and(later_mask, cpu_active_mask, &p->cpus_allowed); > if (cpumask_and(later_mask, later_mask, cp->free_cpus)) { > - best_cpu = cpumask_any(later_mask); > - goto out; > + return 1; > } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) && > dl_time_before(dl_se->deadline, cp->elements[0].dl)) { > - best_cpu = cpudl_maximum(cp); > if (set_flag) > - cpumask_set_cpu(best_cpu, later_mask); > + cpumask_set_cpu(cpudl_maximum(cp), later_mask); > + return 1; > } > > -out: > - WARN_ON(best_cpu != -1 && !cpu_present(best_cpu)); You lost this warning. It should be moved too. > - > - return best_cpu; > + return 0; > } > > /* > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index e8208d0..3e82cf3 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -976,7 +976,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct > task_struct *p) > * let's hope p can move out. > */ > if (rq->curr->nr_cpus_allowed == 1 || > - cpudl_find(&rq->rd->cpudl, rq->curr, later_mask, 0) == -1) > + !cpudl_find(&rq->rd->cpudl, rq->curr, later_mask, 0)) > return; > > /* > @@ -984,7 +984,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct > task_struct *p) > * see if it is pushed or pulled somewhere else. > */ > if (p->nr_cpus_allowed != 1 && > - cpudl_find(&rq->rd->cpudl, p, later_mask, 0) != -1) > + cpudl_find(&rq->rd->cpudl, p, later_mask, 0)) > return; > > resched_curr(rq); > @@ -1189,9 +1189,7 @@ 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, 1); > - if (best_cpu == -1) > + if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask, 1)) > return -1; > > /* > @@ -1230,12 +1228,9 @@ static int find_later_rq(struct task_struct *task) > return this_cpu; > } > > - /* > - * Last chance: if best_cpu is valid and is > - * in the mask, that becomes our choice. > - */ > - if (best_cpu < nr_cpu_ids && > - cpumask_test_cpu(best_cpu, sched_domain_span(sd))) { > + best_cpu = cpumask_first_and(lowest_mask, > + sched_domain_span(sd)); Sometimes that 80 character rule isn't the best for readability. But that is Peter's or Juri's call. > + if (best_cpu < nr_cpu_ids) { The warning should probably go here. -- Steve > rcu_read_unlock(); > return best_cpu; > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
