Function rte_eal_config_create

dpdk/lib/eal/linux/eal.c:175–259

create memory configuration in shared/mmap memory. Take out * a write lock on the memsegs, so we can auto-detect primary/secondary. * This means we never close the file while running (auto-close on exit). * We also don't lock the whole file, so that in future we can use read-locks * on other parts, e.g. memzones, to detect if there are running secondary * processes. */

 * on other parts, e.g. memzones, to detect if there are running secondary
 * processes. */
static int
rte_eal_config_create(void)
{
	struct rte_config *config = rte_eal_get_configuration();
	size_t page_sz = sysconf(_SC_PAGE_SIZE);
	size_t cfg_len = sizeof(*config->mem_config);
	size_t cfg_len_aligned = RTE_ALIGN(cfg_len, page_sz);
	void *rte_mem_cfg_addr, *mapped_mem_cfg_addr;
	int retval;
	const struct internal_config *internal_conf =
		eal_get_internal_configuration();

	const char *pathname = eal_runtime_config_path();

	if (internal_conf->no_shconf)
		return 0;

	/* map the config before hugepage address so that we don't waste a page */
	if (internal_conf->base_virtaddr != 0)
		rte_mem_cfg_addr = (void *)
			RTE_ALIGN_FLOOR(internal_conf->base_virtaddr -
			sizeof(struct rte_mem_config), page_sz);
	else
		rte_mem_cfg_addr = NULL;

	if (mem_cfg_fd < 0){
		mem_cfg_fd = open(pathname, O_RDWR | O_CREAT, 0600);
		if (mem_cfg_fd < 0) {
			RTE_LOG(ERR, EAL, "Cannot open '%s' for rte_mem_config\n",
				pathname);
			return -1;
		}
	}

	retval = ftruncate(mem_cfg_fd, cfg_len);
	if (retval < 0){
		close(mem_cfg_fd);
		mem_cfg_fd = -1;
		RTE_LOG(ERR, EAL, "Cannot resize '%s' for rte_mem_config\n",
			pathname);
		return -1;
	}

	retval = fcntl(mem_cfg_fd, F_SETLK, &wr_lock);
	if (retval < 0){
		close(mem_cfg_fd);
		mem_cfg_fd = -1;
		RTE_LOG(ERR, EAL, "Cannot create lock on '%s'. Is another primary "
			"process running?\n", pathname);
		return -1;
	}

	/* reserve space for config */
	rte_mem_cfg_addr = eal_get_virtual_area(rte_mem_cfg_addr,
			&cfg_len_aligned, page_sz, 0, 0);
	if (rte_mem_cfg_addr == NULL) {
		RTE_LOG(ERR, EAL, "Cannot mmap memory for rte_config\n");
		close(mem_cfg_fd);