Messages in this thread | | | From | Xuewen Yan <> | Date | Fri, 19 Apr 2024 17:20:19 +0800 | Subject | Re: [RFC PATCH] sched/eevdf: Return leftmost entity in pick_eevdf() if no eligible entity is found |
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On Fri, Apr 19, 2024 at 4:45 PM Peter Zijlstra <peterz@infradead.org> wrote: > > On Fri, Apr 19, 2024 at 10:24:40AM +0200, Peter Zijlstra wrote: > > On Thu, Apr 18, 2024 at 09:03:36PM +0800, Chen Yu wrote: > > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > > index 31bca05c3612..9f203012e8f5 100644 > > > --- a/kernel/sched/fair.c > > > +++ b/kernel/sched/fair.c > > > @@ -696,15 +696,23 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq) > > > * > > > * XXX could add max_slice to the augmented data to track this. > > > */ > > > + > > > +static s64 limit_entity_lag(struct sched_entity *se, s64 lag) > > > +{ > > > + s64 limit; > > > + > > > + limit = calc_delta_fair(max_t(u64, 2*se->slice, TICK_NSEC), se); > > > + return clamp(lag, -limit, limit); > > > +} > > > > Right, helper makes sense. > > A possible other helper might be the below. But that depends if we want > to clip after scaling too. No super strong preference. > > Please post your patch with a proper changelog and we'll get it sorted.
Thanks Peter, I will send the v2 later after my local testing:)
> > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -696,15 +696,19 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq) > * > * XXX could add max_slice to the augmented data to track this. > */ > -static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se) > +static s64 entity_lag(u64 avruntime, struct sched_entity *se) > { > - s64 lag, limit; > - > - SCHED_WARN_ON(!se->on_rq); > - lag = avg_vruntime(cfs_rq) - se->vruntime; > + s64 vlag, limit; > > + vlag = avruntime - se->vruntime; > limit = calc_delta_fair(max_t(u64, 2*se->slice, TICK_NSEC), se); > - se->vlag = clamp(lag, -limit, limit); > + return clamp(vlag, -limit, limit); > +} > + > +static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se) > +{ > + SCHED_WARN_ON(!se->on_rq); > + se->vlag = entity_lag(avg_vruntime(cfs_rq), se); > } > > /* > @@ -3760,7 +3764,7 @@ static void reweight_eevdf(struct sched_ > * = V - vl' > */ > if (avruntime != se->vruntime) { > - vlag = (s64)(avruntime - se->vruntime); > + vlag = entity_lag(avruntime, se); > vlag = div_s64(vlag * old_weight, weight); > se->vruntime = avruntime - vlag; > }
BR --- xuewen
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