On Wed, Jan 06, 2021 at 02:34:19PM +0100, Vincent Guittot wrote:
> Active balance is triggered for a number of voluntary case like misfit or
cases
> pinned tasks cases but also after that a number of load balance failed to
^attempts
> migrate a task. Remove the active load balance case for overloaded group
^an ?
> as an overloaded state means that there is at least one waiting tasks. The
task
> threshold on the upper limit of the task's load will decrease with the
> number of failed LB until the task has migrated.
And I'm not sure I follow that last part, irrespective of spelling nits,
help?
> Signed-off-by: Vincent Guittot <[email protected]>
> ---
> kernel/sched/fair.c | 43 +++++++++++++++++++++----------------------
> 1 file changed, 21 insertions(+), 22 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 69a455113b10..ee87fd6f7359 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9499,13 +9499,30 @@ asym_active_balance(struct lb_env *env)
> }
>
> static inline bool
> -voluntary_active_balance(struct lb_env *env)
> +imbalanced_active_balance(struct lb_env *env)
> +{
> + struct sched_domain *sd = env->sd;
> +
> + /* The imbalanced case includes the case of pinned tasks preventing a
> fair
> + * distribution of the load on the system but also the even
> distribution of the
> + * threads on a system with spare capacity
> + */
comment style fail
> + if ((env->migration_type == migrate_task) &&
> + (sd->nr_balance_failed > sd->cache_nice_tries+2))
indent fail; try: set cino=(0:0
> + return 1;
> +
> + return 0;
> +}
> +
> +static int need_active_balance(struct lb_env *env)
> {
> struct sched_domain *sd = env->sd;
>
> if (asym_active_balance(env))
> return 1;
>
> + if (imbalanced_active_balance(env))
> + return 1;
+ whitespace
> /*
> * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
> * It's worth migrating the task if the src_cpu's capacity is reduced
