rte_eal_init详解.txt

int
rte_eal_init(int argc, char **argv)
{
	int i, fctret, ret;
	pthread_t thread_id;
	static rte_atomic32_t run_once = RTE_ATOMIC32_INIT(0);
	const char *logid;
	char cpuset[RTE_CPU_AFFINITY_STR_LEN];
	char thread_name[RTE_MAX_THREAD_NAME_LEN];
	
	//判断run_once是否为1。确保rte_eal_init只调用一次，即只对dpdk做一次初始化。
	if (!rte_atomic32_test_and_set(&run_once))
		return -1;

	logid = strrchr(argv[0], '/');
	logid = strdup(logid ? logid + 1: argv[0]);

	//获取调用rte_eal_init函数的线程的线程id
	thread_id = pthread_self();

	//初始化日志的流。
	if (rte_eal_log_early_init() < 0)
		rte_panic("Cannot init early logs\n");
	
	//通过命令行参数，得到日志等级
	eal_log_level_parse(argc, argv);

	//设置日志等级
	rte_set_log_level(internal_config.log_level);

	//得到CPU核信息，初始化变量struct rte_config *config和struct lcore_config lcore_config[RTE_MAX_LCORE];
	//两个变量都为全局变量，lcore_config用于记录每个核的信息；config用于记录整体信息。
	if (rte_eal_cpu_init() < 0)
		rte_panic("Cannot detect lcores\n");

	//对其他命令行参数进行解析
	fctret = eal_parse_args(argc, argv);
	if (fctret < 0)
		exit(1);

	//获取系统大页的信息，包括：页大小，也要挂载的路径，页个数。。。等。
	if (internal_config.no_hugetlbfs == 0 &&
			internal_config.process_type != RTE_PROC_SECONDARY &&
			internal_config.xen_dom0_support == 0 &&
			eal_hugepage_info_init() < 0)
		rte_panic("Cannot get hugepage information\n");

	if (internal_config.memory == 0 && internal_config.force_sockets == 0) {
		if (internal_config.no_hugetlbfs)
			internal_config.memory = MEMSIZE_IF_NO_HUGE_PAGE;
		else
			internal_config.memory = eal_get_hugepage_mem_size();
	}

	if (internal_config.vmware_tsc_map == 1) 
	{
#ifdef RTE_LIBRTE_EAL_VMWARE_TSC_MAP_SUPPORT
		rte_cycles_vmware_tsc_map = 1;
		RTE_LOG (DEBUG, EAL, "Using VMWARE TSC MAP, "
				"you must have monitor_control.pseudo_perfctr = TRUE\n");
#else
		RTE_LOG (WARNING, EAL, "Ignoring --vmware-tsc-map because "
				"RTE_LIBRTE_EAL_VMWARE_TSC_MAP_SUPPORT is not set\n");
#endif
	}

	//设置随机数种子
	rte_srand(rte_rdtsc());

	//如果是主进程，那么分配rte_config.mem_config(struct rte_mem_config)空间，建立内存映射，便于从进程访问。内存映射路径默认为：/var/run/.rte_config
	//如果是从进程，那么通过内存映射获取主进程rte_config.mem_config的地址并对自己的结构赋值。
	rte_config_init();

	//通过文件/sys/bus/pci/devices，获取所有pci设备的信息
	if (rte_eal_pci_init() < 0)
		rte_panic("Cannot init PCI\n");

#ifdef RTE_LIBRTE_IVSHMEM
	if (rte_eal_ivshmem_init() < 0)
		rte_panic("Cannot init IVSHMEM\n");
#endif
	
	//------如果是主进程调用函数rte_eal_hugepage_init，那么对大页做如下初始化;
	//1.为每个大页建立一个内存映射文件，默认建立路径为：/mnt/huge
	//2.通过内存映射的虚拟地址得到物理地址
	//3.得到大页的socket id
	//4.重新组织大页，将大页连续的虚拟地址和物理地址，已经想通的也大小和socket的页，作为一个整体，便于分配，保存到变量rte_config.mem_config.memseg中。
	//5.创建一个/var/run/.rte_hugepage_info文件，用于保存每个大页的rte_hugepage_info结构。
	
	//--------如果是从进程调用rte_eal_hugepage_attach，那么将其attach到大页中:
	//1.第一次映射判断是否能够联系映射
	//2.通过读取/var/run/.rte_hugepage_info文件的也信息结构，通过计算得到页个数
	//3。然后通过信息进行映射
	if (rte_eal_memory_init() < 0)
		rte_panic("Cannot init memory\n");

	/* the directories are locked during eal_hugepage_info_init */
	eal_hugedirs_unlock();

	//通过rte_confige.rte_mem_config.memseg建立内存链表，其中memzone为内存分配器。
	if (rte_eal_memzone_init() < 0)
		rte_panic("Cannot init memzone\n");

	if (rte_eal_tailqs_init() < 0)
		rte_panic("Cannot init tail queues for objects\n");

#ifdef RTE_LIBRTE_IVSHMEM
	if (rte_eal_ivshmem_obj_init() < 0)
		rte_panic("Cannot init IVSHMEM objects\n");
#endif

	if (rte_eal_log_init(logid, internal_config.syslog_facility) < 0)
		rte_panic("Cannot init logs\n");

	if (rte_eal_alarm_init() < 0)
		rte_panic("Cannot init interrupt-handling thread\n");

	if (rte_eal_timer_init() < 0)
		rte_panic("Cannot init HPET or TSC timers\n");

	eal_check_mem_on_local_socket();

	if (eal_plugins_init() < 0)
		rte_panic("Cannot init plugins\n");

	eal_thread_init_master(rte_config.master_lcore);

	ret = eal_thread_dump_affinity(cpuset, RTE_CPU_AFFINITY_STR_LEN);

	RTE_LOG(DEBUG, EAL, "Master lcore %u is ready (tid=%x;cpuset=[%s%s])\n",
		rte_config.master_lcore, (int)thread_id, cpuset,
		ret == 0 ? "" : "...");

	//通过得到的dev_driver_list，遍历dev_driver_list，调用每个driver的初始化函数，将驱动注册到pci_driver_list中，元素结构体为rte_pci_driver。
	//rte_eal_init[eal.c] ------> rte_eal_dev_init[eal.c]  -----> 遍历dev_driver_list列表，调用每个driver的init（driver->init(......)）
	//	rte_eth_driver_register[eal_commmon_pci.c](注册设备初始化函数和卸载函数	rte_eth_dev_init与rte_eth_dev_uninit)
	//	-----> rte_eal_pci_register[eal_commmon_pci.c] ----> TAILQ_INSERT_TAIL(&pci_driver_list, driver, next)
	if (rte_eal_dev_init() < 0)
		rte_panic("Cannot init pmd devices\n");

	if (rte_eal_intr_init() < 0)
		rte_panic("Cannot init interrupt-handling thread\n");

	RTE_LCORE_FOREACH_SLAVE(i) {

		/*
		 * create communication pipes between master thread
		 * and children
		 */
		if (pipe(lcore_config[i].pipe_master2slave) < 0)
			rte_panic("Cannot create pipe\n");
		if (pipe(lcore_config[i].pipe_slave2master) < 0)
			rte_panic("Cannot create pipe\n");

		lcore_config[i].state = WAIT;

		/* create a thread for each lcore */
		ret = pthread_create(&lcore_config[i].thread_id, NULL,
				     eal_thread_loop, NULL);
		if (ret != 0)
			rte_panic("Cannot create thread\n");

		/* Set thread_name for aid in debugging. */
		snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN,
			"lcore-slave-%d", i);
		ret = rte_thread_setname(lcore_config[i].thread_id,
						thread_name);
		if (ret != 0)
			RTE_LOG(ERR, EAL,
				"Cannot set name for lcore thread\n");
	}

	/*
	 * Launch a dummy function on all slave lcores, so that master lcore
	 * knows they are all ready when this function returns.
	 */
	rte_eal_mp_remote_launch(sync_func, NULL, SKIP_MASTER);
	rte_eal_mp_wait_lcore();

	//rte_eal_init[eal.c] ------> rte_eal_pci_probe[eal_commmon_pci.c] ----> 遍历pci_device_list，循环调用pci_probe_all_drivers[eal_commmon_pci.c]
	//	-----> 遍历pci_driver_list，循环调用rte_eal_pci_probe_one_driver[eal_commmon_pci.c] ----> 循环查找驱动列表，找到对应PCI设备的驱动
	//	通过比较4个参数来确认匹配(vendor_id、device_id、subsystem_vendor_id、subsystem_device_id)，并判断驱动名称是否和dpdk自己实现的驱动名称相同 
	//	----> 调用devinit函数进行初始化为rte_eth_dev_init[rte_ethdev.c] ----->其中会调用驱动eth_driver的eth_dev_init函数，此函数在驱动文件中
	if (rte_eal_pci_probe())
		rte_panic("Cannot probe PCI\n");

	rte_eal_mcfg_complete();

	return fctret;
}