Messages in this thread Patch in this message | | | Date | Sat, 28 May 2011 22:34:00 +0800 | Subject | [PATCH] sched: change pulling RT task to be pulling the highest-prio run-queue first | From | Hillf Danton <> |
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When pulling, RT tasks are pulled from one overloaded run-queue after another, which is changed to be pulling tasks from the highest-prio run-queue first.
A new function, cpupri_find_prio(), is added to easy pulling in prio sequence.
Signed-off-by: Hillf Danton <dhillf@gmail.com> ---
--- tip-git/kernel/sched_rt.c Sun May 22 20:12:01 2011 +++ sched_rt.c Sat May 28 21:24:13 2011 @@ -1434,18 +1434,33 @@ static void push_rt_tasks(struct rq *rq) ; }
+static DEFINE_PER_CPU(cpumask_var_t, high_cpu_mask); + static int pull_rt_task(struct rq *this_rq) { int this_cpu = this_rq->cpu, ret = 0, cpu; struct task_struct *p; struct rq *src_rq; + struct cpumask *high_mask = __get_cpu_var(high_cpu_mask); + int prio = 0;
if (likely(!rt_overloaded(this_rq))) return 0; +loop: + if (! (prio < this_rq->rt.highest_prio.curr)) + return ret; + + if (! cpupri_find_prio(&this_rq->rd->cpupri, prio, + this_rq->rd->rto_mask, high_mask)) { + prio++; + goto loop; + }
- for_each_cpu(cpu, this_rq->rd->rto_mask) { - if (this_cpu == cpu) - continue; + if (cpumask_test_cpu(this_cpu, high_mask)) + /* no efforts needed if this RQ is high enough in prio */ + return ret; + + for_each_cpu(cpu, high_mask) {
src_rq = cpu_rq(cpu);
@@ -1508,8 +1523,13 @@ static int pull_rt_task(struct rq *this_ } skip: double_unlock_balance(this_rq, src_rq); + if (ret) + goto done; }
+ prio++; + goto loop; +done: return ret; }
@@ -1630,9 +1650,12 @@ static inline void init_sched_rt_class(v { unsigned int i;
- for_each_possible_cpu(i) + for_each_possible_cpu(i) { zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i), GFP_KERNEL, cpu_to_node(i)); + zalloc_cpumask_var_node(&per_cpu(high_cpu_mask, i), + GFP_KERNEL, cpu_to_node(i)); + } } #endif /* CONFIG_SMP */
--- tip-git/kernel/sched_cpupri.h Sat May 14 15:21:56 2011 +++ sched_cpupri.h Sat May 28 21:29:26 2011 @@ -26,6 +26,7 @@ struct cpupri { #ifdef CONFIG_SMP int cpupri_find(struct cpupri *cp, struct task_struct *p, struct cpumask *lowest_mask); +int cpupri_find_prio(struct cpupri *,int, struct cpumask *, struct cpumask *); void cpupri_set(struct cpupri *cp, int cpu, int pri); int cpupri_init(struct cpupri *cp); void cpupri_cleanup(struct cpupri *cp); --- tip-git/kernel/sched_cpupri.c Sat May 14 15:21:56 2011 +++ sched_cpupri.c Sat May 28 21:46:51 2011 @@ -202,3 +202,33 @@ void cpupri_cleanup(struct cpupri *cp) for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) free_cpumask_var(cp->pri_to_cpu[i].mask); } + +/* + * cpupri_find_prio - find CPUs for a given prio + * @cp: The cpupri context + * @task_prio: The given prio for which CPUs are slected + * @filter_mask: A mask to filter selected CPUs + * @ret_mask: A mask to fill in with selected CPUs + * + * Returns: (int)bool - CPUs were found + */ +int cpupri_find_prio(struct cpupri *cp, int task_prio, + struct cpumask *filter_mask, + struct cpumask *ret_mask) +{ + task_prio = convert_prio(task_prio); + + if (cp->pri_active[task_prio / BITS_PER_LONG] & + (1UL << (task_prio % BITS_PER_LONG))) { + + struct cpupri_vec *vec = &cp->pri_to_cpu[task_prio]; + + cpumask_and(ret_mask, filter_mask, vec->mask); + + if (cpumask_any(ret_mask) < nr_cpu_ids) + return 1; + } + + return 0; +} +
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