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| author | Toshi Kani <toshi.kani@hp.com> | 2013-07-19 19:47:48 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-07-22 11:13:34 +0200 |
| commit | a0842b704b0f7c2d925473676f2012ea5dc39976 (patch) | |
| tree | 6abaf5122cd924cbe083b168ea3e94264b6d6b73 /arch/x86/Kconfig | |
| parent | Linux 3.11-rc2 (diff) | |
| download | linux-a0842b704b0f7c2d925473676f2012ea5dc39976.tar.xz linux-a0842b704b0f7c2d925473676f2012ea5dc39976.zip | |
mm/hotplug, x86: Disable ARCH_MEMORY_PROBE by default
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: Toshi Kani <toshi.kani@hp.com>
Acked-by: KOSAKI 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: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index b32ebf92b0ce..2f9d95775d27 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1344,8 +1344,12 @@ config ARCH_SELECT_MEMORY_MODEL depends on ARCH_SPARSEMEM_ENABLE config ARCH_MEMORY_PROBE - def_bool y + bool "Enable sysfs memory/probe interface" 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 |