On 08/01/2013 12:06 AM, Tang Chen wrote: > This patch-set aims to solve some problems at system boot time > to enhance memory hotplug functionality. > > [Background] > > The Linux kernel cannot migrate pages used by the kernel because > of the kernel direct mapping. Since va = pa + PAGE_OFFSET, if the > physical address is changed, we cannot simply update the kernel > pagetable. On the contrary, we have to update all the pointers > pointing to the virtual address, which is very difficult to do. > It does beg the question if that "since" statement should be changed ... we already have it handled differently on Xen PV, but that is kind of "special". There are a whole bunch of other issues with moving kernel memory around: you have to worry what might have a physical address cached somewhere and what might be in active use and so on... I am not really suggesting it as anything but food for thought at this time. -hpa -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>