Function eal_get_virtual_area

dpdk/lib/eal/common/eal_common_memory.c:46–201

#define MAX_MMAP_WITH_DEFINED_ADDR_TRIES 5
void *
eal_get_virtual_area(void *requested_addr, size_t *size,
	size_t page_sz, int flags, int reserve_flags)
{
	bool addr_is_hint, allow_shrink, unmap, no_align;
	uint64_t map_sz;
	void *mapped_addr, *aligned_addr;
	uint8_t try = 0;
	struct internal_config *internal_conf =
		eal_get_internal_configuration();

	if (system_page_sz == 0)
		system_page_sz = rte_mem_page_size();

	RTE_LOG(DEBUG, EAL, "Ask a virtual area of 0x%zx bytes\n", *size);

	addr_is_hint = (flags & EAL_VIRTUAL_AREA_ADDR_IS_HINT) > 0;
	allow_shrink = (flags & EAL_VIRTUAL_AREA_ALLOW_SHRINK) > 0;
	unmap = (flags & EAL_VIRTUAL_AREA_UNMAP) > 0;

	if (next_baseaddr == NULL && internal_conf->base_virtaddr != 0 &&
			rte_eal_process_type() == RTE_PROC_PRIMARY)
		next_baseaddr = (void *) internal_conf->base_virtaddr;

#ifdef RTE_ARCH_64
	if (next_baseaddr == NULL && internal_conf->base_virtaddr == 0 &&
			rte_eal_process_type() == RTE_PROC_PRIMARY)
		next_baseaddr = (void *) eal_get_baseaddr();
#endif
	if (requested_addr == NULL && next_baseaddr != NULL) {
		requested_addr = next_baseaddr;
		requested_addr = RTE_PTR_ALIGN(requested_addr, page_sz);
		addr_is_hint = true;
	}

	/* we don't need alignment of resulting pointer in the following cases:
	 *
	 * 1. page size is equal to system size
	 * 2. we have a requested address, and it is page-aligned, and we will
	 *    be discarding the address if we get a different one.
	 *
	 * for all other cases, alignment is potentially necessary.
	 */
	no_align = (requested_addr != NULL &&
		requested_addr == RTE_PTR_ALIGN(requested_addr, page_sz) &&
		!addr_is_hint) ||
		page_sz == system_page_sz;

	do {
		map_sz = no_align ? *size : *size + page_sz;
		if (map_sz > SIZE_MAX) {
			RTE_LOG(ERR, EAL, "Map size too big\n");
			rte_errno = E2BIG;
			return NULL;
		}

		mapped_addr = eal_mem_reserve(
			requested_addr, (size_t)map_sz, reserve_flags);