Messages in this thread | | | Date | Mon, 24 Oct 2022 14:34:35 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH 1/2] sched/numa: Stop an exhastive search if an idle core is found |
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On Fri, Oct 21, 2022 at 02:15:57PM +0800, Hao Jia wrote: > In update_numa_stats() we try to find an idle cpu on the NUMA node, > preferably an idle core. When we find an idle core, > we can stop searching. > > Signed-off-by: Hao Jia <jiahao.os@bytedance.com> > --- > kernel/sched/fair.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index e4a0b8bd941c..b7cbec539c77 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1792,7 +1792,7 @@ static void update_numa_stats(struct task_numa_env *env, > ns->nr_running += rq->cfs.h_nr_running; > ns->compute_capacity += capacity_of(cpu); > > - if (find_idle && !rq->nr_running && idle_cpu(cpu)) { > + if (find_idle && idle_core < 0 && !rq->nr_running && idle_cpu(cpu)) { > if (READ_ONCE(rq->numa_migrate_on) || > !cpumask_test_cpu(cpu, env->p->cpus_ptr)) > continue; > @@ -1801,6 +1801,9 @@ static void update_numa_stats(struct task_numa_env *env, > ns->idle_cpu = cpu; > > idle_core = numa_idle_core(idle_core, cpu); > + /* If we find an idle core, stop searching. */ > + if (idle_core >= 0) > + ns->idle_cpu = idle_core; > } > } > rcu_read_unlock(); > @@ -1808,9 +1811,6 @@ static void update_numa_stats(struct task_numa_env *env, > ns->weight = cpumask_weight(cpumask_of_node(nid)); > > ns->node_type = numa_classify(env->imbalance_pct, ns); > - > - if (idle_core >= 0) > - ns->idle_cpu = idle_core; > } >
Remove the change in the first hunk and call break in the second hunk after updating ns->idle_cpu.
-- Mel Gorman SUSE Labs
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