From: He Yujie <coka.heyujie@huawei.com> hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB42TC -------------------------------- After the preferred_cpu goes offline, the core selection of dynamic affinity does not check whether the preferred_cpu is valid. As a result, related dynamic affinity processes are concentrated on a shared_cpu. This patch resolves this problem to checks whether the preferred_cpu is valid and compares only the usage threshold of the valid preferred_cpu. Fixes: 2e1dfc02d115 ("sched: Adjust wakeup cpu range according CPU util dynamicly") Signed-off-by: He Yujie <coka.heyujie@huawei.com> Signed-off-by: Cheng Yu <serein.chengyu@huawei.com> --- kernel/sched/fair.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5fc8d6a25b9a..437572c568ee 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8124,6 +8124,7 @@ static void set_task_select_cpus(struct task_struct *p, int *idlest_cpu, struct task_group *tg; long spare; int cpu, mode; + int nr_cpus_valid = 0; rcu_read_lock(); mode = dynamic_affinity_mode(p); @@ -8141,7 +8142,7 @@ static void set_task_select_cpus(struct task_struct *p, int *idlest_cpu, /* manual mode */ tg = task_group(p); - for_each_cpu(cpu, p->prefer_cpus) { + for_each_cpu_and(cpu, p->prefer_cpus, cpu_online_mask) { if (idlest_cpu && (available_idle_cpu(cpu) || sched_idle_cpu(cpu))) { *idlest_cpu = cpu; } else if (idlest_cpu) { @@ -8163,10 +8164,17 @@ static void set_task_select_cpus(struct task_struct *p, int *idlest_cpu, util_avg_sum += taskgroup_cpu_util(tg, cpu); tg_capacity += capacity_of(cpu); + nr_cpus_valid++; } rcu_read_unlock(); - if (tg_capacity > cpumask_weight(p->prefer_cpus) && + /* + * Follow cases should select cpus_ptr, checking by condition of + * tg_capacity > nr_cpus_valid: + * 1. all prefer_cpus offline; + * 2. all prefer_cpus has no cfs capaicity(tg_capacity = nr_cpus_valid * 1) + */ + if (tg_capacity > nr_cpus_valid && util_avg_sum * 100 <= tg_capacity * sysctl_sched_util_low_pct) { p->select_cpus = p->prefer_cpus; if (sd_flag & SD_BALANCE_WAKE) -- 2.25.1