blk-mq: map all HWQ also in hyperthreaded system (fe631457) · Commits · 戴 / test

block/blk-mq-cpumap.c

+22 −46

Original line number	Diff line number	Diff line
		@@ -14,10 +14,15 @@
		#include "blk.h"
		#include "blk-mq.h"

		static int cpu_to_queue_index(unsigned int nr_cpus, unsigned int nr_queues,
		const int cpu)
		static int cpu_to_queue_index(unsigned int nr_queues, const int cpu,
		const struct cpumask *online_mask)
		{
		return cpu * nr_queues / nr_cpus;
		/*
		* Non online CPU will be mapped to queue index 0.
		*/
		if (!cpumask_test_cpu(cpu, online_mask))
		return 0;
		return cpu % nr_queues;
		}

		static int get_first_sibling(unsigned int cpu)
		@@ -36,55 +41,26 @@ int blk_mq_map_queues(struct blk_mq_tag_set *set)
		unsigned int *map = set->mq_map;
		unsigned int nr_queues = set->nr_hw_queues;
		const struct cpumask *online_mask = cpu_online_mask;
		unsigned int i, nr_cpus, nr_uniq_cpus, queue, first_sibling;
		cpumask_var_t cpus;

		if (!alloc_cpumask_var(&cpus, GFP_ATOMIC))
		return -ENOMEM;

		cpumask_clear(cpus);
		nr_cpus = nr_uniq_cpus = 0;
		for_each_cpu(i, online_mask) {
		nr_cpus++;
		first_sibling = get_first_sibling(i);
		if (!cpumask_test_cpu(first_sibling, cpus))
		nr_uniq_cpus++;
		cpumask_set_cpu(i, cpus);
		}

		queue = 0;
		for_each_possible_cpu(i) {
		if (!cpumask_test_cpu(i, online_mask)) {
		map[i] = 0;
		continue;
		}
		unsigned int cpu, first_sibling;

		for_each_possible_cpu(cpu) {
		/*
		* Easy case - we have equal or more hardware queues. Or
		* there are no thread siblings to take into account. Do
		* 1:1 if enough, or sequential mapping if less.
		* First do sequential mapping between CPUs and queues.
		* In case we still have CPUs to map, and we have some number of
		* threads per cores then map sibling threads to the same queue for
		* performace optimizations.
		*/
		if (nr_queues >= nr_cpus \|\| nr_cpus == nr_uniq_cpus) {
		map[i] = cpu_to_queue_index(nr_cpus, nr_queues, queue);
		queue++;
		continue;
		if (cpu < nr_queues) {
		map[cpu] = cpu_to_queue_index(nr_queues, cpu, online_mask);
		} else {
		first_sibling = get_first_sibling(cpu);
		if (first_sibling == cpu)
		map[cpu] = cpu_to_queue_index(nr_queues, cpu, online_mask);
		else
		map[cpu] = map[first_sibling];
		}

		/*
		* Less then nr_cpus queues, and we have some number of
		* threads per cores. Map sibling threads to the same
		* queue.
		*/
		first_sibling = get_first_sibling(i);
		if (first_sibling == i) {
		map[i] = cpu_to_queue_index(nr_uniq_cpus, nr_queues,
		queue);
		queue++;
		} else
		map[i] = map[first_sibling];
		}

		free_cpumask_var(cpus);
		return 0;
		}
		EXPORT_SYMBOL_GPL(blk_mq_map_queues);

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