Re: [PATCH 9/9] v4 Update memory-hotplug documentation

From: KAMEZAWA Hiroyuki
Date: Thu Aug 05 2010 - 01:09:10 EST


On Tue, 03 Aug 2010 08:44:16 -0500
Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote:

> Update the memory hotplug documentation to reflect the new behaviors of
> memory blocks reflected in sysfs.
>
> Signed-off-by: Nathan Fontenot <nfont@xxxxxxxxxxxxxx>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

A request from me:

Could you clarify what happens if there are memory hole in [start end)_phys_index.
in Documentation ? (Or add TODO list.)

Thanks,
-Kame


> ---
> Documentation/memory-hotplug.txt | 40 +++++++++++++++++++++++----------------
> 1 file changed, 24 insertions(+), 16 deletions(-)
>
> Index: linux-2.6/Documentation/memory-hotplug.txt
> ===================================================================
> --- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-08-02 14:09:28.000000000 -0500
> +++ linux-2.6/Documentation/memory-hotplug.txt 2010-08-02 14:10:36.000000000 -0500
> @@ -126,36 +126,44 @@ config options.
> --------------------------------
> 4 sysfs files for memory hotplug
> --------------------------------
> -All sections have their device information under /sys/devices/system/memory as
> +All sections have their device information in sysfs. Each section is part of
> +a memory block under /sys/devices/system/memory as
>
> /sys/devices/system/memory/memoryXXX
> -(XXX is section id.)
> +(XXX is the section id.)
>
> -Now, XXX is defined as start_address_of_section / section_size.
> +Now, XXX is defined as (start_address_of_section / section_size) of the first
> +section contained in the memory block.
>
> For example, assume 1GiB section size. A device for a memory starting at
> 0x100000000 is /sys/device/system/memory/memory4
> (0x100000000 / 1Gib = 4)
> This device covers address range [0x100000000 ... 0x140000000)
>
> -Under each section, you can see 4 files.
> +Under each section, you can see 5 files.
>
> -/sys/devices/system/memory/memoryXXX/phys_index
> +/sys/devices/system/memory/memoryXXX/start_phys_index
> +/sys/devices/system/memory/memoryXXX/end_phys_index
> /sys/devices/system/memory/memoryXXX/phys_device
> /sys/devices/system/memory/memoryXXX/state
> /sys/devices/system/memory/memoryXXX/removable
>
> -'phys_index' : read-only and contains section id, same as XXX.
> -'state' : read-write
> - at read: contains online/offline state of memory.
> - at write: user can specify "online", "offline" command
> -'phys_device': read-only: designed to show the name of physical memory device.
> - This is not well implemented now.
> -'removable' : read-only: contains an integer value indicating
> - whether the memory section is removable or not
> - removable. A value of 1 indicates that the memory
> - section is removable and a value of 0 indicates that
> - it is not removable.
> +'phys_index' : read-only and contains section id of the first section
> + in the memory block, same as XXX.
> +'end_phys_index' : read-only and contains section id of the last section
> + in the memory block.
> +'state' : read-write
> + at read: contains online/offline state of memory.
> + at write: user can specify "online", "offline" command
> + which will be performed on al sections in the block.
> +'phys_device' : read-only: designed to show the name of physical memory
> + device. This is not well implemented now.
> +'removable' : read-only: contains an integer value indicating
> + whether the memory block is removable or not
> + removable. A value of 1 indicates that the memory
> + block is removable and a value of 0 indicates that
> + it is not removable. A memory block is removable only if
> + every section in the block is removable.
>
> NOTE:
> These directories/files appear after physical memory hotplug phase.
>
>
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