Messages in this thread Patch in this message | | | Date | Thu, 13 Dec 2018 14:52:08 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 3/3] sched/fair: fix unnecessary increase of balance interval |
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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?
--- 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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