On Wed, Jul 17, 2013 at 7:51 PM, Toshi Kani <[email protected]> wrote: > On Wed, 2013-07-17 at 19:33 -0400, KOSAKI Motohiro wrote: >> On Wed, Jul 17, 2013 at 7:29 PM, Toshi Kani <[email protected]> wrote: >> > On Wed, 2013-07-17 at 19:22 -0400, KOSAKI Motohiro wrote: >> >> On Wed, Jul 17, 2013 at 5:45 PM, Toshi Kani <[email protected]> wrote: >> >> > CONFIG_ARCH_MEMORY_PROBE enables /sys/devices/system/memory/probe >> >> > interface, which allows a given memory address to be hot-added as >> >> > follows. (See Documentation/memory-hotplug.txt for more detail.) >> >> > >> >> > # echo start_address_of_new_memory > /sys/devices/system/memory/probe >> >> > >> >> > This probe interface is required on powerpc. On x86, however, ACPI >> >> > notifies a memory hotplug event to the kernel, which performs its >> >> > hotplug operation as the result. Therefore, users should not be >> >> > required to use this interface on x86. This probe interface is also >> >> > error-prone that the kernel blindly adds a given memory address >> >> > without checking if the memory is present on the system; no probing >> >> > is done despite of its name. The kernel crashes when a user requests >> >> > to online a memory block that is not present on the system. >> >> > >> >> > This patch disables CONFIG_ARCH_MEMORY_PROBE by default on x86, >> >> > and clarifies it in Documentation/memory-hotplug.txt. >> >> >> >> Why don't you completely remove it? Who should use this strange interface? >> > >> > According to the comment below, this probe interface is used on powerpc. >> > So, we cannot remove it, but to disable it on x86. >> >> I meant x86. Why can't we completely remove ARCH_MEMORY_PROBE section >> from x86 Kconfig? > > Oh, I see what you meant. I do not expect any need for end-users, but I > was not sure if someone working on the memory hotplug development might > use it for fake hot-add testing. Yes, if you folks do not see any need, > I will remove it from x86 Kconfig.
Then it's ok to submit your patch now. Acked-by: KOSAKI Motohiro <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
