example/nvmf: Create and destroy lightweight thread per poll groups dynamically (bda55ddb) · Commits · Public Repositories / spdk

examples/nvmf/nvmf/nvmf.c

+72 −51

Original line number	Diff line number	Diff line
		@@ -90,10 +90,12 @@ struct nvmf_target {

		TAILQ_HEAD(, nvmf_reactor) g_reactors = TAILQ_HEAD_INITIALIZER(g_reactors);
		TAILQ_HEAD(, nvmf_target_poll_group) g_poll_groups = TAILQ_HEAD_INITIALIZER(g_poll_groups);
		static uint32_t g_num_poll_groups = 0;

		static struct nvmf_reactor *g_master_reactor = NULL;
		static struct nvmf_reactor *g_next_reactor = NULL;
		static struct spdk_thread *g_init_thread = NULL;
		static struct spdk_thread *g_fini_thread = NULL;
		static struct nvmf_target g_nvmf_tgt = {
		.max_subsystems = NVMF_DEFAULT_SUBSYSTEMS,
		};
		@@ -606,11 +608,23 @@ nvmf_tgt_start_subsystems(struct nvmf_target *nvmf_tgt)
		static void
		nvmf_tgt_create_poll_groups_done(void *ctx)
		{
		struct nvmf_target_poll_group *pg = ctx;

		if (!g_next_pg) {
		g_next_pg = pg;
		}

		TAILQ_INSERT_TAIL(&g_poll_groups, pg, link);

		assert(g_num_poll_groups < spdk_env_get_core_count());

		if (++g_num_poll_groups == spdk_env_get_core_count()) {
		fprintf(stdout, "create targets's poll groups done\n");

		g_target_state = NVMF_INIT_START_SUBSYSTEMS;
		nvmf_target_advance_state();
		}
		}

		static void
		nvmf_tgt_create_poll_group(void *ctx)
		@@ -620,6 +634,7 @@ nvmf_tgt_create_poll_group(void *ctx)
		pg = calloc(1, sizeof(struct nvmf_target_poll_group));
		if (!pg) {
		fprintf(stderr, "failed to allocate poll group\n");
		assert(false);
		return;
		}

		@@ -628,78 +643,84 @@ nvmf_tgt_create_poll_group(void *ctx)
		if (!pg->group) {
		fprintf(stderr, "failed to create poll group of the target\n");
		free(pg);
		assert(false);
		return;
		}

		if (!g_next_pg) {
		g_next_pg = pg;
		spdk_thread_send_msg(g_init_thread, nvmf_tgt_create_poll_groups_done, pg);
		}

		/* spdk_for_each_channel is asynchronous, but runs on each thread in serial.
		* Since this is the only operation occurring on the g_poll_groups list,
		* we don't need to take a lock.
		/* Create a lightweight thread per poll group instead of assuming a pool of lightweight
		* threads already exist at start up time. A poll group is a collection of unrelated NVMe-oF
		* connections. Each poll group is only accessed from the associated lightweight thread.
		*/
		TAILQ_INSERT_TAIL(&g_poll_groups, pg, link);
		}

		static void
		nvmf_poll_groups_create(void)
		{
		/* Send a message to each thread and create a poll group.
		* Pgs are used to handle all the connections from the host so we
		* would like to create one pg in each core. We use the spdk_for_each
		* _thread because we have allocated one lightweight thread per core in
		* thread layer. You can also do this by traversing reactors
		* or SPDK_ENV_FOREACH_CORE().
		*/
		spdk_for_each_thread(nvmf_tgt_create_poll_group,
		NULL,
		nvmf_tgt_create_poll_groups_done);
		struct spdk_cpuset tmp_cpumask = {};
		uint32_t i;
		char thread_name[32];
		struct spdk_thread *thread;

		assert(g_init_thread != NULL);

		SPDK_ENV_FOREACH_CORE(i) {
		spdk_cpuset_zero(&tmp_cpumask);
		spdk_cpuset_set_cpu(&tmp_cpumask, i, true);
		snprintf(thread_name, sizeof(thread_name), "nvmf_tgt_poll_group_%u", i);

		thread = spdk_thread_create(thread_name, &tmp_cpumask);
		assert(thread != NULL);

		spdk_thread_send_msg(thread, nvmf_tgt_create_poll_group, NULL);
		}
		}

		static void
		nvmf_tgt_destroy_poll_groups_done(struct spdk_io_channel_iter *i, int status)
		_nvmf_tgt_destroy_poll_groups_done(void *ctx)
		{
		assert(g_num_poll_groups > 0);

		if (--g_num_poll_groups == 0) {
		fprintf(stdout, "destroy targets's poll groups done\n");

		g_target_state = NVMF_FINI_STOP_ACCEPTOR;
		nvmf_target_advance_state();
		}
		}

		static void
		nvmf_tgt_destroy_poll_group(struct spdk_io_channel_iter *i)
		nvmf_tgt_destroy_poll_groups_done(void *cb_arg, int status)
		{
		struct spdk_io_channel *io_ch = spdk_io_channel_iter_get_channel(i);
		struct spdk_nvmf_poll_group *group = spdk_io_channel_get_ctx(io_ch);
		struct nvmf_target_poll_group pg, tmp;
		struct nvmf_target_poll_group *pg = cb_arg;

		/* Spdk_for_each_channel is asynchronous but executes serially.
		* That means only a single thread is executing this callback at a time,
		* so we can safely touch the g_poll_groups list without a lock.
		*/
		TAILQ_FOREACH_SAFE(pg, &g_poll_groups, link, tmp) {
		if (pg->group == group) {
		TAILQ_REMOVE(&g_poll_groups, pg, link);
		spdk_nvmf_poll_group_destroy(group, NULL, NULL);
		free(pg);
		break;
		}

		spdk_thread_send_msg(g_fini_thread, _nvmf_tgt_destroy_poll_groups_done, NULL);

		spdk_thread_exit(spdk_get_thread());
		}

		spdk_for_each_channel_continue(i, 0);
		static void
		nvmf_tgt_destroy_poll_group(void *ctx)
		{
		struct nvmf_target_poll_group *pg = ctx;

		spdk_nvmf_poll_group_destroy(pg->group, nvmf_tgt_destroy_poll_groups_done, pg);
		}

		static void
		nvmf_poll_groups_destroy(void)
		{
		/* Send a message to each channel and destroy the poll group.
		* Poll groups are I/O channels associated with the spdk_nvmf_tgt object.
		* To iterate all poll groups, we can use spdk_for_each_channel.
		*/
		spdk_for_each_channel(g_nvmf_tgt.tgt,
		nvmf_tgt_destroy_poll_group,
		NULL,
		nvmf_tgt_destroy_poll_groups_done);
		struct nvmf_target_poll_group pg, tmp;

		g_fini_thread = spdk_get_thread();
		assert(g_fini_thread != NULL);

		TAILQ_FOREACH_SAFE(pg, &g_poll_groups, link, tmp) {
		TAILQ_REMOVE(&g_poll_groups, pg, link);
		spdk_thread_send_msg(pg->thread, nvmf_tgt_destroy_poll_group, pg);
		}
		}

		static void

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