Messages in this thread | | | From | Vincent Guittot <> | Date | Thu, 13 Dec 2018 16:36:14 +0100 | Subject | Re: [PATCH 3/3] sched/fair: fix unnecessary increase of balance interval |
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On Thu, 13 Dec 2018 at 14:52, Peter Zijlstra <peterz@infradead.org> wrote: > > On Tue, Aug 07, 2018 at 05:56:27PM +0200, Vincent Guittot wrote: > > +static inline bool > > +asym_active_balance(enum cpu_idle_type idle, unsigned int flags, int dst, int src) > > { > > + if (idle != CPU_NOT_IDLE) { > > > > /* > > * ASYM_PACKING needs to force migrate tasks from busy but > > * lower priority CPUs in order to pack all tasks in the > > * highest priority CPUs. > > */ > > + if ((flags & SD_ASYM_PACKING) && > > + sched_asym_prefer(dst, src)) > > + return true; > > } > > > > + return false; > > +} > > + > > +static int need_active_balance(struct lb_env *env) > > +{ > > + struct sched_domain *sd = env->sd; > > + > > + > > + if (asym_active_balance(env->idle, sd->flags, env->dst_cpu, env->src_cpu)) > > + return 1; > > + > > /* > > * 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 > > @@ -8650,7 +8660,8 @@ static int load_balance(int this_cpu, struct rq *this_rq, > > } else > > sd->nr_balance_failed = 0; > > > > + if (likely(!active_balance) || > > + asym_active_balance(env.idle, sd->flags, env.dst_cpu, env.src_cpu)) { > > Perhaps like the below?
Yes. Far more simple and readable
> > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8857,21 +8857,24 @@ static struct rq *find_busiest_queue(str > */ > #define MAX_PINNED_INTERVAL 512 > > +static inline bool > +asym_active_balance(struct lb_env *env) > +{ > + /* > + * ASYM_PACKING needs to force migrate tasks from busy but > + * lower priority CPUs in order to pack all tasks in the > + * highest priority CPUs. > + */ > + return env->idle != CPU_NOT_IDLE && (env->sd->flags & SD_ASYM_PACKING) && > + sched_asym_prefer(env->dst_cpu, env->src_cpu); > +} > + > static int need_active_balance(struct lb_env *env) > { > struct sched_domain *sd = env->sd; > > - if (env->idle != CPU_NOT_IDLE) { > - > - /* > - * ASYM_PACKING needs to force migrate tasks from busy but > - * lower priority CPUs in order to pack all tasks in the > - * highest priority CPUs. > - */ > - if ((sd->flags & SD_ASYM_PACKING) && > - sched_asym_prefer(env->dst_cpu, env->src_cpu)) > - return 1; > - } > + if (asym_active_balance(env)) > + return 1; > > /* > * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task. > @@ -9150,7 +9153,7 @@ static int load_balance(int this_cpu, st > } else > sd->nr_balance_failed = 0; > > - if (likely(!active_balance)) { > + if (likely(!active_balance) || asym_active_balance(&env)) { > /* We were unbalanced, so reset the balancing interval */ > sd->balance_interval = sd->min_interval; > } else {
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