On Sun, Jan 12, 2014 at 6:46 PM, Prarit Bhargava <prarit@xxxxxxxxxx> wrote: > > > On 01/11/2014 11:35 AM, 7eggert@xxxxxx wrote: >> >> >> On Fri, 10 Jan 2014, Prarit Bhargava wrote: >> >>> kdump uses memmap=exactmap and mem=X values to configure the memory >>> mapping for the kdump kernel. If memory is hotadded during the boot of >>> the kdump kernel it is possible that the page tables for the new memory >>> cause the kdump kernel to run out of memory. >>> >>> Since the user has specified a specific mapping ACPI Memory Hotplug should be >>> disabled in this case. >> >> I'll ask just in case: Is it possible to want memory hotplug in spite of >> using memmap=exactmap or mem=X? > > Good question -- I can't think of a case. When a user specifies "memmap" or > "mem" IMO they are asking for a very specific memory configuration. Having > extra memory added above what the user has specified seems to defeat the purpose > of "memmap" and "mem". May be yes, may be no. They are often used for a wrokaround to avoid broken firmware issue. If we have no way to explicitly enable hotplug. We will lose a workaround. Perhaps, there is no matter. Today, memory hotplug is only used on high-end machine and their firmware is carefully developped and don't have a serious issue almostly. Though. -- 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>