• Toshi Kani's avatar
    mm/hotplug, x86: Disable ARCH_MEMORY_PROBE by default · a0842b70
    Toshi Kani authored
    CONFIG_ARCH_MEMORY_PROBE enables the
    /sys/devices/system/memory/probe interface, which allows a given
    memory address to be hot-added as follows:
    
     # echo start_address_of_new_memory > /sys/devices/system/memory/probe
    
    (See Documentation/memory-hotplug.txt for more details.)
    
    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: default avatarToshi Kani <toshi.kani@hp.com>
    Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Cc: linux-mm@kvack.org
    Cc: dave@sr71.net
    Cc: isimatu.yasuaki@jp.fujitsu.com
    Cc: tangchen@cn.fujitsu.com
    Cc: vasilis.liaskovitis@profitbricks.com
    Link: http://lkml.kernel.org/r/1374256068-26016-1-git-send-email-toshi.kani@hp.com
    [ Edited it slightly. ]
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    a0842b70
memory-hotplug.txt 16.1 KB