static void __init setup_memory()

in kernel/setup.c [242:287]

• 29 lines of code
• 4 McCabe index (conditional complexity)

static void __init setup_memory(void)
{
	unsigned long ram_start_pfn;
	unsigned long free_ram_start_pfn;
	phys_addr_t memory_start, memory_end;

	memory_end = memory_start = 0;

	/* Find main memory where is the kernel */
	memory_start = memblock_start_of_DRAM();
	memory_end = memblock_end_of_DRAM();

	if (!memory_end) {
		panic("No memory!");
	}

	ram_start_pfn = PFN_UP(memblock_start_of_DRAM());
	/* free_ram_start_pfn is first page after kernel */
	free_ram_start_pfn = PFN_UP(__pa(&_end));
	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
	/* it could update max_pfn */
	if (max_pfn - ram_start_pfn <= MAXMEM_PFN)
		max_low_pfn = max_pfn;
	else {
		max_low_pfn = MAXMEM_PFN + ram_start_pfn;
		if (!IS_ENABLED(CONFIG_HIGHMEM))
			max_pfn = MAXMEM_PFN + ram_start_pfn;
	}
	/* high_memory is related with VMALLOC */
	high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
	min_low_pfn = free_ram_start_pfn;

	/*
	 * initialize the boot-time allocator (with low memory only).
	 *
	 * This makes the memory from the end of the kernel to the end of
	 * RAM usable.
	 */
	memblock_set_bottom_up(true);
	memblock_reserve(PFN_PHYS(ram_start_pfn), PFN_PHYS(free_ram_start_pfn - ram_start_pfn));

	early_init_fdt_reserve_self();
	early_init_fdt_scan_reserved_mem();

	memblock_dump_all();
}