From: Jon Medhurst (Tixy) Date: Fri, 2 Aug 2013 17:45:33 +0000 (+0100) Subject: HMP: Check the system has little cpus before forcing rt tasks onto them X-Git-Tag: firefly_0821_release~3680^2~5^2~3^2~19 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c5021c1eb9c73f38209180c65bd074ac70c97587;p=firefly-linux-kernel-4.4.55.git HMP: Check the system has little cpus before forcing rt tasks onto them It is sometimes desirable to run a kernel with HMP scheduling enabled on a system which is not big.LITTLE, e.g. when building a multi-platform kernel, or when testing a big.LITTLE system with one cluster disabled. We should therefore allow for the situation where is no little domain. Signed-off-by: Jon Medhurst Signed-off-by: Mark Brown --- diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 50d9e9849ce7..fb9b7b74a836 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3841,8 +3841,9 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) if (rt_prio(p->prio)) { p->sched_class = &rt_sched_class; #ifdef CONFIG_SCHED_HMP - if (cpumask_equal(&p->cpus_allowed, cpu_all_mask)) - do_set_cpus_allowed(p, &hmp_slow_cpu_mask); + if (!cpumask_empty(&hmp_slow_cpu_mask)) + if (cpumask_equal(&p->cpus_allowed, cpu_all_mask)) + do_set_cpus_allowed(p, &hmp_slow_cpu_mask); #endif } else