Messages in this thread | | | Date | Thu, 20 Nov 2014 17:00:20 +0800 | From | Wanpeng Li <> | Subject | Re: [PATCH v2 1/4] sched/deadline: Modify cpudl.free_cpus to reflect rd->span |
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Hi, On 11/19/14, 11:46 PM, pang.xunlei wrote: > Currently, cpudl.free_cpus contains all cpus during init(see cpudl_init()), > so when calling cpudl_find() we have to add rd->span cpumask(cpus_allowed is > undependable when performing clustered scheduling using the cpuset) to avoid > selecting the cpu outside current root domain, see find_later_rq(). > > This patch adds cpudl_set_freecpu() to initialize cpudl.free_cpus when doing > rq_attach_root(), so we can avoid the extra rd->span operation when calling > cpudl_find(). > > Signed-off-by: pang.xunlei <pang.xunlei@linaro.org>
Reviewed-by: Wanpeng Li <wanpeng.li@linux.intel.com>
I think this patch solve one problem I meet in my progress to handle dl task migration during cpu hotplug. https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg770579.html
Regards, Wanpeng Li
> --- > kernel/sched/core.c | 2 ++ > kernel/sched/cpudeadline.c | 18 ++++++++++++++---- > kernel/sched/cpudeadline.h | 1 + > kernel/sched/deadline.c | 3 --- > 4 files changed, 17 insertions(+), 7 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 240157c..1b417de 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -5584,6 +5584,8 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd) > rq->rd = rd; > > cpumask_set_cpu(rq->cpu, rd->span); > + cpudl_set_freecpu(&rd->cpudl, rq->cpu); > + > if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) > set_rq_online(rq); > > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c > index 539ca3c..c79f0d7 100644 > --- a/kernel/sched/cpudeadline.c > +++ b/kernel/sched/cpudeadline.c > @@ -107,7 +107,9 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, > int best_cpu = -1; > const struct sched_dl_entity *dl_se = &p->dl; > > - if (later_mask && cpumask_and(later_mask, later_mask, cp->free_cpus)) { > + if (later_mask && > + cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed) && > + cpumask_and(later_mask, later_mask, cpu_active_mask)) { > best_cpu = cpumask_any(later_mask); > goto out; > } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) && > @@ -186,6 +188,16 @@ out: > } > > /* > + * cpudl_set_freecpu - Set the cpudl.free_cpus > + * @cp: the cpudl max-heap context > + * @cpu: rd attached cpu > + */ > +void cpudl_set_freecpu(struct cpudl *cp, int cpu) > +{ > + cpumask_set_cpu(cpu, cp->free_cpus); > +} > + > +/* > * cpudl_init - initialize the cpudl structure > * @cp: the cpudl max-heap context > */ > @@ -203,7 +215,7 @@ int cpudl_init(struct cpudl *cp) > if (!cp->elements) > return -ENOMEM; > > - if (!alloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) { > + if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) { > kfree(cp->elements); > return -ENOMEM; > } > @@ -211,8 +223,6 @@ int cpudl_init(struct cpudl *cp) > for_each_possible_cpu(i) > cp->elements[i].idx = IDX_INVALID; > > - cpumask_setall(cp->free_cpus); > - > return 0; > } > > diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h > index 020039b..4a10a65 100644 > --- a/kernel/sched/cpudeadline.h > +++ b/kernel/sched/cpudeadline.h > @@ -24,6 +24,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, > struct cpumask *later_mask); > void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid); > int cpudl_init(struct cpudl *cp); > +void cpudl_set_freecpu(struct cpudl *cp, int cpu); > void cpudl_cleanup(struct cpudl *cp); > #endif /* CONFIG_SMP */ > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 5285332..bd83272 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1187,9 +1187,6 @@ static int find_later_rq(struct task_struct *task) > * We have to consider system topology and task affinity > * first, then we can look for a suitable cpu. > */ > - cpumask_copy(later_mask, task_rq(task)->rd->span); > - cpumask_and(later_mask, later_mask, cpu_active_mask); > - cpumask_and(later_mask, later_mask, &task->cpus_allowed); > best_cpu = cpudl_find(&task_rq(task)->rd->cpudl, > task, later_mask); > if (best_cpu == -1)
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