evie/android_kernel_oneplus_msm8998
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sched: Enable idle balance to pull single task towards cpu with higher capacity

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We do not want to miss out on the ability to pull a single remaining
task from a potential source cpu towards an idle destination cpu. Add an
extra criteria to need_active_balance() to kick off active load balance
if the source cpu is over-utilized and has lower capacity than the
destination cpu.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
This commit is contained in:
Dietmar Eggemann 2015-01-26 19:47:28 +00:00 • committed by Leo Yan
parent 8a5c0339bb
commit cda2bd333b
1 changed files with 12 additions and 0 deletions
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12
kernel/sched/fair.c
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@ -4779,6 +4779,11 @@ static inline bool task_fits_spare(struct task_struct *p, int cpu)
return __task_fits(p, cpu, cpu_util(cpu));
}
static bool cpu_overutilized(int cpu)
{
return (capacity_of(cpu) * 1024) < (cpu_util(cpu) * capacity_margin);
}
/*
* find_idlest_group finds and returns the least busy CPU group within the
* domain.
@ -6995,6 +7000,13 @@ static int need_active_balance(struct lb_env *env)
return 1;
}
if ((capacity_of(env->src_cpu) < capacity_of(env->dst_cpu)) &&
env->src_rq->cfs.h_nr_running == 1 &&
cpu_overutilized(env->src_cpu) &&
!cpu_overutilized(env->dst_cpu)) {
return 1;
}
return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
}