sched: RT-balance, optimize cpu search (610bf056) · Commits · 戴 / test

kernel/sched_rt.c

+36 −13

Original line number	Diff line number	Diff line
		@@ -296,29 +296,36 @@ static struct task_struct pick_next_highest_task_rt(struct rq rq,
		}

		static DEFINE_PER_CPU(cpumask_t, local_cpu_mask);
		static DEFINE_PER_CPU(cpumask_t, valid_cpu_mask);

		static int find_lowest_cpus(struct task_struct task, cpumask_t lowest_mask)
		{
		int cpu;
		cpumask_t *valid_mask = &__get_cpu_var(valid_cpu_mask);
		int lowest_prio = -1;
		int lowest_cpu = -1;
		int count = 0;
		int cpu;

		cpus_clear(*lowest_mask);
		cpus_and(*valid_mask, cpu_online_map, task->cpus_allowed);
		cpus_and(*lowest_mask, cpu_online_map, task->cpus_allowed);

		/*
		* Scan each rq for the lowest prio.
		*/
		for_each_cpu_mask(cpu, *valid_mask) {
		for_each_cpu_mask(cpu, *lowest_mask) {
		struct rq *rq = cpu_rq(cpu);

		/* We look for lowest RT prio or non-rt CPU */
		if (rq->rt.highest_prio >= MAX_RT_PRIO) {
		if (count)
		/*
		* if we already found a low RT queue
		* and now we found this non-rt queue
		* clear the mask and set our bit.
		* Otherwise just return the queue as is
		* and the count==1 will cause the algorithm
		* to use the first bit found.
		*/
		if (lowest_cpu != -1) {
		cpus_clear(*lowest_mask);
		cpu_set(rq->cpu, *lowest_mask);
		}
		return 1;
		}

		@@ -328,13 +335,29 @@ static int find_lowest_cpus(struct task_struct task, cpumask_t lowest_mask)
		if (rq->rt.highest_prio > lowest_prio) {
		/* new low - clear old data */
		lowest_prio = rq->rt.highest_prio;
		if (count) {
		cpus_clear(*lowest_mask);
		lowest_cpu = cpu;
		count = 0;
		}
		}
		cpu_set(rq->cpu, *lowest_mask);
		count++;
		} else
		cpu_clear(cpu, *lowest_mask);
		}

		/*
		* Clear out all the set bits that represent
		* runqueues that were of higher prio than
		* the lowest_prio.
		*/
		if (lowest_cpu > 0) {
		/*
		* Perhaps we could add another cpumask op to
		* zero out bits. Like cpu_zero_bits(cpumask, nrbits);
		* Then that could be optimized to use memset and such.
		*/
		for_each_cpu_mask(cpu, *lowest_mask) {
		if (cpu >= lowest_cpu)
		break;
		cpu_clear(cpu, *lowest_mask);
		}
		}

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