diff options
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 174 |
1 files changed, 68 insertions, 106 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 54ce787b6207..579da278e72f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1021,8 +1021,59 @@ static int find_idlest_cpu(struct sched_group *group, int this_cpu) return idlest; } +/* + * sched_balance_self: balance the current task (running on cpu) in domains + * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and + * SD_BALANCE_EXEC. + * + * Balance, ie. select the least loaded group. + * + * Returns the target CPU number, or the same CPU if no balancing is needed. + * + * preempt must be disabled. + */ +static int sched_balance_self(int cpu, int flag) +{ + struct task_struct *t = current; + struct sched_domain *tmp, *sd = NULL; -#endif + for_each_domain(cpu, tmp) + if (tmp->flags & flag) + sd = tmp; + + while (sd) { + cpumask_t span; + struct sched_group *group; + int new_cpu; + int weight; + + span = sd->span; + group = find_idlest_group(sd, t, cpu); + if (!group) + goto nextlevel; + + new_cpu = find_idlest_cpu(group, cpu); + if (new_cpu == -1 || new_cpu == cpu) + goto nextlevel; + + /* Now try balancing at a lower domain level */ + cpu = new_cpu; +nextlevel: + sd = NULL; + weight = cpus_weight(span); + for_each_domain(cpu, tmp) { + if (weight <= cpus_weight(tmp->span)) + break; + if (tmp->flags & flag) + sd = tmp; + } + /* while loop will break here if sd == NULL */ + } + + return cpu; +} + +#endif /* CONFIG_SMP */ /* * wake_idle() will wake a task on an idle cpu if task->cpu is @@ -1240,8 +1291,15 @@ int fastcall wake_up_state(task_t *p, unsigned int state) * Perform scheduler related setup for a newly forked process p. * p is forked by current. */ -void fastcall sched_fork(task_t *p) +void fastcall sched_fork(task_t *p, int clone_flags) { + int cpu = get_cpu(); + +#ifdef CONFIG_SMP + cpu = sched_balance_self(cpu, SD_BALANCE_FORK); +#endif + set_task_cpu(p, cpu); + /* * We mark the process as running here, but have not actually * inserted it onto the runqueue yet. This guarantees that @@ -1282,12 +1340,10 @@ void fastcall sched_fork(task_t *p) * runqueue lock is not a problem. */ current->time_slice = 1; - preempt_disable(); scheduler_tick(); - local_irq_enable(); - preempt_enable(); - } else - local_irq_enable(); + } + local_irq_enable(); + put_cpu(); } /* @@ -1302,64 +1358,12 @@ void fastcall wake_up_new_task(task_t * p, unsigned long clone_flags) unsigned long flags; int this_cpu, cpu; runqueue_t *rq, *this_rq; -#ifdef CONFIG_SMP - struct sched_domain *tmp, *sd = NULL; -#endif rq = task_rq_lock(p, &flags); BUG_ON(p->state != TASK_RUNNING); this_cpu = smp_processor_id(); cpu = task_cpu(p); -#ifdef CONFIG_SMP - for_each_domain(cpu, tmp) - if (tmp->flags & SD_BALANCE_FORK) - sd = tmp; - - if (sd) { - cpumask_t span; - int new_cpu; - struct sched_group *group; - -again: - schedstat_inc(sd, sbf_cnt); - span = sd->span; - cpu = task_cpu(p); - group = find_idlest_group(sd, p, cpu); - if (!group) { - schedstat_inc(sd, sbf_balanced); - goto nextlevel; - } - - new_cpu = find_idlest_cpu(group, cpu); - if (new_cpu == -1 || new_cpu == cpu) { - schedstat_inc(sd, sbf_balanced); - goto nextlevel; - } - - if (cpu_isset(new_cpu, p->cpus_allowed)) { - schedstat_inc(sd, sbf_pushed); - set_task_cpu(p, new_cpu); - task_rq_unlock(rq, &flags); - rq = task_rq_lock(p, &flags); - cpu = task_cpu(p); - } - - /* Now try balancing at a lower domain level */ -nextlevel: - sd = NULL; - for_each_domain(cpu, tmp) { - if (cpus_subset(span, tmp->span)) - break; - if (tmp->flags & SD_BALANCE_FORK) - sd = tmp; - } - - if (sd) - goto again; - } - -#endif /* * We decrease the sleep average of forking parents * and children as well, to keep max-interactive tasks @@ -1708,58 +1712,16 @@ out: } /* - * sched_exec(): find the highest-level, exec-balance-capable - * domain and try to migrate the task to the least loaded CPU. - * - * execve() is a valuable balancing opportunity, because at this point - * the task has the smallest effective memory and cache footprint. + * sched_exec - execve() is a valuable balancing opportunity, because at + * this point the task has the smallest effective memory and cache footprint. */ void sched_exec(void) { - struct sched_domain *tmp, *sd = NULL; int new_cpu, this_cpu = get_cpu(); - - for_each_domain(this_cpu, tmp) - if (tmp->flags & SD_BALANCE_EXEC) - sd = tmp; - - if (sd) { - cpumask_t span; - struct sched_group *group; -again: - schedstat_inc(sd, sbe_cnt); - span = sd->span; - group = find_idlest_group(sd, current, this_cpu); - if (!group) { - schedstat_inc(sd, sbe_balanced); - goto nextlevel; - } - new_cpu = find_idlest_cpu(group, this_cpu); - if (new_cpu == -1 || new_cpu == this_cpu) { - schedstat_inc(sd, sbe_balanced); - goto nextlevel; - } - - schedstat_inc(sd, sbe_pushed); - put_cpu(); - sched_migrate_task(current, new_cpu); - - /* Now try balancing at a lower domain level */ - this_cpu = get_cpu(); -nextlevel: - sd = NULL; - for_each_domain(this_cpu, tmp) { - if (cpus_subset(span, tmp->span)) - break; - if (tmp->flags & SD_BALANCE_EXEC) - sd = tmp; - } - - if (sd) - goto again; - } - + new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); put_cpu(); + if (new_cpu != this_cpu) + sched_migrate_task(current, new_cpu); } /* |