Give every class a set_cpus_allowed() method, this enables some small optimization in the rt,dl implementation by avoiding a double cpumask_weight() call.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- kernel/sched/core.c | 17 +++++++++++------ kernel/sched/deadline.c | 20 ++++++++++++-------- kernel/sched/fair.c | 1 + kernel/sched/idle_task.c | 1 + kernel/sched/rt.c | 12 ++++++++---- kernel/sched/sched.h | 2 ++ kernel/sched/stop_task.c | 1 + 7 files changed, 36 insertions(+), 18 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4791,17 +4791,22 @@ static struct rq *move_queued_task(struc return rq; } -void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) +/* + * sched_class::set_cpus_allowed must do the below, but is not required to + * actually call this function. + */ +void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask) { - lockdep_assert_held(&p->pi_lock); - - if (p->sched_class->set_cpus_allowed) - p->sched_class->set_cpus_allowed(p, new_mask); - cpumask_copy(&p->cpus_allowed, new_mask); p->nr_cpus_allowed = cpumask_weight(new_mask); } +void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) +{ + lockdep_assert_held(&p->pi_lock); + p->sched_class->set_cpus_allowed(p, new_mask); +} + /* * This is how migration works: * --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1597,13 +1597,6 @@ static void set_cpus_allowed_dl(struct t raw_spin_unlock(&src_dl_b->lock); } - /* - * Update only if the task is actually running (i.e., - * it is on the rq AND it is not throttled). - */ - if (!on_dl_rq(&p->dl)) - return; - weight = cpumask_weight(new_mask); /* @@ -1611,7 +1604,14 @@ static void set_cpus_allowed_dl(struct t * can migrate or not. */ if ((p->nr_cpus_allowed > 1) == (weight > 1)) - return; + goto done; + + /* + * Update only if the task is actually running (i.e., + * it is on the rq AND it is not throttled). + */ + if (!on_dl_rq(&p->dl)) + goto done; /* * The process used to be able to migrate OR it can now migrate @@ -1628,6 +1628,10 @@ static void set_cpus_allowed_dl(struct t } update_dl_migration(&rq->dl); + +done: + cpumask_copy(&p->cpus_allowed, new_mask); + p->nr_cpus_allowed = weight; } /* Assumes rq->lock is held */ --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8406,6 +8406,7 @@ const struct sched_class fair_sched_clas .rq_offline = rq_offline_fair, .task_waking = task_waking_fair, + .set_cpus_allowed = set_cpus_allowed_common, #endif .set_curr_task = set_curr_task_fair, --- a/kernel/sched/idle_task.c +++ b/kernel/sched/idle_task.c @@ -96,6 +96,7 @@ const struct sched_class idle_sched_clas #ifdef CONFIG_SMP .select_task_rq = select_task_rq_idle, + .set_cpus_allowed = set_cpus_allowed_common, #endif .set_curr_task = set_curr_task_idle, --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2065,9 +2065,6 @@ static void set_cpus_allowed_rt(struct t BUG_ON(!rt_task(p)); - if (!task_on_rq_queued(p)) - return; - weight = cpumask_weight(new_mask); /* @@ -2075,7 +2072,10 @@ static void set_cpus_allowed_rt(struct t * can migrate or not. */ if ((p->nr_cpus_allowed > 1) == (weight > 1)) - return; + goto done; + + if (!task_on_rq_queued(p)) + goto done; rq = task_rq(p); @@ -2094,6 +2094,10 @@ static void set_cpus_allowed_rt(struct t } update_rt_migration(&rq->rt); + +done: + cpumask_copy(&p->cpus_allowed, new_mask); + p->nr_cpus_allowed = weight; } /* Assumes rq->lock is held */ --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1252,6 +1252,8 @@ extern void trigger_load_balance(struct extern void idle_enter_fair(struct rq *this_rq); extern void idle_exit_fair(struct rq *this_rq); +extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask); + #else static inline void idle_enter_fair(struct rq *rq) { } --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -123,6 +123,7 @@ const struct sched_class stop_sched_clas #ifdef CONFIG_SMP .select_task_rq = select_task_rq_stop, + .set_cpus_allowed = set_cpus_allowed_common, #endif .set_curr_task = set_curr_task_stop, -- 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/
