如何從linux內核獲取物理內存，包括保留內存？

Question

來自 linux 的 proc.txt：

MemTotal: Total usable ram (i.e. physical ram minus a few reserved

但是如何從 linux 內核獲取包括保留內存在內的整個物理內存？

Answer 1

physpages = get_num_physpages();

pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
#ifdef  CONFIG_HIGHMEM
        ", %luK highmem"
#endif
        "%s%s)\n",
        nr_free_pages() << (PAGE_SHIFT - 10),
        physpages << (PAGE_SHIFT - 10),
        codesize >> 10, datasize >> 10, rosize >> 10,
        (init_data_size + init_code_size) >> 10, bss_size >> 10,
        (physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
        totalcma_pages << (PAGE_SHIFT - 10),
#ifdef  CONFIG_HIGHMEM
        totalhigh_pages() << (PAGE_SHIFT - 10),
#endif
        str ? ", " : "", str ? str : "");

所以get_num_physpages << (PAGE_SHIFT - 10)將獲得整個物理內存。