mem=nn[KMG]     [KNL,BOOT] Force usage of a specific amount of memory

                        Amount of memory to be used when the kernel is not able

                        to see the whole system memory or for test.

                        [IA-32] Use together with memmap= to avoid physical

                        address space collisions. Without memmap= PCI devices

                        could be placed at addresses belonging to unused RAM.


        mem=nopentium   [BUGS=IA-32] Disable usage of 4MB pages for kernel

                        memory.


        memmap=exactmap [KNL,IA-32] Enable setting of an exact

                        E820 memory map, as specified by the user.

                        Such memmap=exactmap lines can be constructed based on

                        BIOS output or other requirements. See the memmap=nn@ss

                        option description.


        memmap=nn[KMG]@ss[KMG]

                        [KNL] Force usage of a specific region of memory

                        Region of memory to be used, from ss to ss+nn.


        memmap=nn[KMG]#ss[KMG]

                        [KNL,ACPI] Mark specific memory as ACPI data.

                        Region of memory to be used, from ss to ss+nn.


        memmap=nn[KMG]$ss[KMG]

                        [KNL,ACPI] Mark specific memory as reserved.

                        Region of memory to be used, from ss to ss+nn.


引入时间为2005年，遗迹参见：http://lwn.net/Articles/132338/

更多命令行请参考 http://www.cyberciti.biz/howto/question/static/linux-kernel-parameters.php