Subject: [merged] mm-hotplug-x86-disable-arch_memory_probe-by-default.patch removed from -mm tree To: toshi.kani@xxxxxx,dave@xxxxxxxx,hpa@xxxxxxxxx,isimatu.yasuaki@xxxxxxxxxxxxxx,kosaki.motohiro@xxxxxxxxxxxxxx,mingo@xxxxxxx,tangchen@xxxxxxxxxxxxxx,tglx@xxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 31 Jul 2013 11:30:58 -0700 The patch titled Subject: mm/hotplug, x86: disable ARCH_MEMORY_PROBE by default has been removed from the -mm tree. Its filename was mm-hotplug-x86-disable-arch_memory_probe-by-default.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Toshi Kani <toshi.kani@xxxxxx> Subject: mm/hotplug, x86: disable ARCH_MEMORY_PROBE by default 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, regular users do not need this interface on x86. This probe interface is also error-prone and misleading 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 interface is currently used for testing as it can fake a hotplug event. This patch disables CONFIG_ARCH_MEMORY_PROBE by default on x86, adds its Kconfig menu entry on x86, and clarifies its use in Documentation/ memory-hotplug.txt. Signed-off-by: Toshi Kani <toshi.kani@xxxxxx> Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Dave Hansen <dave@xxxxxxxx> Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/memory-hotplug.txt | 14 ++++++++------ arch/x86/Kconfig | 7 ++++++- 2 files changed, 14 insertions(+), 7 deletions(-) diff -puN Documentation/memory-hotplug.txt~mm-hotplug-x86-disable-arch_memory_probe-by-default Documentation/memory-hotplug.txt --- a/Documentation/memory-hotplug.txt~mm-hotplug-x86-disable-arch_memory_probe-by-default +++ a/Documentation/memory-hotplug.txt @@ -210,13 +210,15 @@ If memory device is found, memory hotplu 4.2 Notify memory hot-add event by hand ------------ -In some environments, especially virtualized environment, firmware will not -notify memory hotplug event to the kernel. For such environment, "probe" -interface is supported. This interface depends on CONFIG_ARCH_MEMORY_PROBE. +On powerpc, the firmware does not notify a memory hotplug event to the kernel. +Therefore, "probe" interface is supported to notify the event to the kernel. +This interface depends on CONFIG_ARCH_MEMORY_PROBE. -Now, CONFIG_ARCH_MEMORY_PROBE is supported only by powerpc but it does not -contain highly architecture codes. Please add config if you need "probe" -interface. +CONFIG_ARCH_MEMORY_PROBE is supported on powerpc only. On x86, this config +option is disabled by default since ACPI notifies a memory hotplug event to +the kernel, which performs its hotplug operation as the result. Please +enable this option if you need the "probe" interface for testing purposes +on x86. Probe interface is located at /sys/devices/system/memory/probe diff -puN arch/x86/Kconfig~mm-hotplug-x86-disable-arch_memory_probe-by-default arch/x86/Kconfig --- a/arch/x86/Kconfig~mm-hotplug-x86-disable-arch_memory_probe-by-default +++ a/arch/x86/Kconfig @@ -1344,8 +1344,13 @@ config ARCH_SELECT_MEMORY_MODEL depends on ARCH_SPARSEMEM_ENABLE config ARCH_MEMORY_PROBE - def_bool y + bool "Enable sysfs memory/probe interface" + default n depends on X86_64 && MEMORY_HOTPLUG + help + This option enables a sysfs memory/probe interface for testing. + See Documentation/memory-hotplug.txt for more information. + If you are unsure how to answer this question, answer N. config ARCH_PROC_KCORE_TEXT def_bool y _ Patches currently in -mm which might be from toshi.kani@xxxxxx are linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html