| Message ID | 1568878421-12301-9-git-send-email-vincent.guittot@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | sched/fair: rework the CFS load balance | expand |
On 19/09/2019 08:33, Vincent Guittot wrote: > utilization is used to detect a misfit task but the load is then used to > select the task on the CPU which can lead to select a small task with > high weight instead of the task that triggered the misfit migration. > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > Acked-by: Valentin Schneider <valentin.schneider@arm.com> > --- > kernel/sched/fair.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index a7c8ee6..acca869 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7429,14 +7429,8 @@ static int detach_tasks(struct lb_env *env) > break; > > case migrate_misfit: > - load = task_h_load(p); > - > - /* > - * utilization of misfit task might decrease a bit > - * since it has been recorded. Be conservative in the > - * condition. > - */ > - if (load < env->imbalance) > + /* This is not a misfit task */ > + if (task_fits_capacity(p, capacity_of(env->src_cpu))) > goto next; > > env->imbalance = 0; > Following my comment in [1], if you can't squash that in patch 04 then perhaps you could add that to this change: --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1fac444a4831..d09ce304161d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8343,7 +8343,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s if (busiest->group_type == group_misfit_task) { /* Set imbalance to allow misfit task to be balanced. */ env->balance_type = migrate_misfit; - env->imbalance = busiest->group_misfit_task_load; + env->imbalance = 1; return; } --- Reason being we don't care about the load (anymore), we just want a nonzero imbalance value, so might as well assign something static. [1]: https://lore.kernel.org/r/74bb33d7-3ba4-aabe-c7a2-3865d5759281@arm.com
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a7c8ee6..acca869 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7429,14 +7429,8 @@ static int detach_tasks(struct lb_env *env) break; case migrate_misfit: - load = task_h_load(p); - - /* - * utilization of misfit task might decrease a bit - * since it has been recorded. Be conservative in the - * condition. - */ - if (load < env->imbalance) + /* This is not a misfit task */ + if (task_fits_capacity(p, capacity_of(env->src_cpu))) goto next; env->imbalance = 0;