diff options
-rw-r--r-- | kernel/sched.c | 78 |
1 files changed, 45 insertions, 33 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 540147e5e82b..934f615ccceb 100644 --- a/kernel/sched.c +++ b/kernel/sched.c | |||
@@ -3487,8 +3487,8 @@ group_next: | |||
3487 | 3487 | ||
3488 | /** | 3488 | /** |
3489 | * fix_small_imbalance - Calculate the minor imbalance that exists | 3489 | * fix_small_imbalance - Calculate the minor imbalance that exists |
3490 | * amongst the groups of a sched_domain, during | 3490 | * amongst the groups of a sched_domain, during |
3491 | * load balancing. | 3491 | * load balancing. |
3492 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. | 3492 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. |
3493 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. | 3493 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. |
3494 | * @imbalance: Variable to store the imbalance. | 3494 | * @imbalance: Variable to store the imbalance. |
@@ -3549,6 +3549,47 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, | |||
3549 | if (pwr_move > pwr_now) | 3549 | if (pwr_move > pwr_now) |
3550 | *imbalance = sds->busiest_load_per_task; | 3550 | *imbalance = sds->busiest_load_per_task; |
3551 | } | 3551 | } |
3552 | |||
3553 | /** | ||
3554 | * calculate_imbalance - Calculate the amount of imbalance present within the | ||
3555 | * groups of a given sched_domain during load balance. | ||
3556 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. | ||
3557 | * @this_cpu: Cpu for which currently load balance is being performed. | ||
3558 | * @imbalance: The variable to store the imbalance. | ||
3559 | */ | ||
3560 | static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, | ||
3561 | unsigned long *imbalance) | ||
3562 | { | ||
3563 | unsigned long max_pull; | ||
3564 | /* | ||
3565 | * In the presence of smp nice balancing, certain scenarios can have | ||
3566 | * max load less than avg load(as we skip the groups at or below | ||
3567 | * its cpu_power, while calculating max_load..) | ||
3568 | */ | ||
3569 | if (sds->max_load < sds->avg_load) { | ||
3570 | *imbalance = 0; | ||
3571 | return fix_small_imbalance(sds, this_cpu, imbalance); | ||
3572 | } | ||
3573 | |||
3574 | /* Don't want to pull so many tasks that a group would go idle */ | ||
3575 | max_pull = min(sds->max_load - sds->avg_load, | ||
3576 | sds->max_load - sds->busiest_load_per_task); | ||
3577 | |||
3578 | /* How much load to actually move to equalise the imbalance */ | ||
3579 | *imbalance = min(max_pull * sds->busiest->__cpu_power, | ||
3580 | (sds->avg_load - sds->this_load) * sds->this->__cpu_power) | ||
3581 | / SCHED_LOAD_SCALE; | ||
3582 | |||
3583 | /* | ||
3584 | * if *imbalance is less than the average load per runnable task | ||
3585 | * there is no gaurantee that any tasks will be moved so we'll have | ||
3586 | * a think about bumping its value to force at least one task to be | ||
3587 | * moved | ||
3588 | */ | ||
3589 | if (*imbalance < sds->busiest_load_per_task) | ||
3590 | return fix_small_imbalance(sds, this_cpu, imbalance); | ||
3591 | |||
3592 | } | ||
3552 | /******* find_busiest_group() helpers end here *********************/ | 3593 | /******* find_busiest_group() helpers end here *********************/ |
3553 | 3594 | ||
3554 | /* | 3595 | /* |
@@ -3562,7 +3603,6 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, | |||
3562 | int *sd_idle, const struct cpumask *cpus, int *balance) | 3603 | int *sd_idle, const struct cpumask *cpus, int *balance) |
3563 | { | 3604 | { |
3564 | struct sd_lb_stats sds; | 3605 | struct sd_lb_stats sds; |
3565 | unsigned long max_pull; | ||
3566 | 3606 | ||
3567 | memset(&sds, 0, sizeof(sds)); | 3607 | memset(&sds, 0, sizeof(sds)); |
3568 | 3608 | ||
@@ -3605,36 +3645,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, | |||
3605 | if (sds.max_load <= sds.busiest_load_per_task) | 3645 | if (sds.max_load <= sds.busiest_load_per_task) |
3606 | goto out_balanced; | 3646 | goto out_balanced; |
3607 | 3647 | ||
3608 | /* | 3648 | /* Looks like there is an imbalance. Compute it */ |
3609 | * In the presence of smp nice balancing, certain scenarios can have | 3649 | calculate_imbalance(&sds, this_cpu, imbalance); |
3610 | * max load less than avg load(as we skip the groups at or below | ||
3611 | * its cpu_power, while calculating max_load..) | ||
3612 | */ | ||
3613 | if (sds.max_load < sds.avg_load) { | ||
3614 | *imbalance = 0; | ||
3615 | fix_small_imbalance(&sds, this_cpu, imbalance); | ||
3616 | goto ret_busiest; | ||
3617 | } | ||
3618 | |||
3619 | /* Don't want to pull so many tasks that a group would go idle */ | ||
3620 | max_pull = min(sds.max_load - sds.avg_load, | ||
3621 | sds.max_load - sds.busiest_load_per_task); | ||
3622 | |||
3623 | /* How much load to actually move to equalise the imbalance */ | ||
3624 | *imbalance = min(max_pull * sds.busiest->__cpu_power, | ||
3625 | (sds.avg_load - sds.this_load) * sds.this->__cpu_power) | ||
3626 | / SCHED_LOAD_SCALE; | ||
3627 | |||
3628 | /* | ||
3629 | * if *imbalance is less than the average load per runnable task | ||
3630 | * there is no gaurantee that any tasks will be moved so we'll have | ||
3631 | * a think about bumping its value to force at least one task to be | ||
3632 | * moved | ||
3633 | */ | ||
3634 | if (*imbalance < sds.busiest_load_per_task) | ||
3635 | fix_small_imbalance(&sds, this_cpu, imbalance); | ||
3636 | |||
3637 | ret_busiest: | ||
3638 | return sds.busiest; | 3650 | return sds.busiest; |
3639 | 3651 | ||
3640 | out_balanced: | 3652 | out_balanced: |