On Wed, Jul 17, 2013 at 7:29 PM, Toshi Kani <toshi.kani@xxxxxx> wrote: > On Wed, 2013-07-17 at 19:22 -0400, KOSAKI Motohiro wrote: >> On Wed, Jul 17, 2013 at 5:45 PM, Toshi Kani <toshi.kani@xxxxxx> 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? -- 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>