[PATCH 8/8] v3 Update memory-hotplug documentation
nfont at austin.ibm.com
Tue Jul 20 13:59:59 EST 2010
Update the memory hotplug documentation to reflect the new behaviors of
memory blocks reflected in sysfs.
Signed-off-by: Nathan Fontent <nfont at austin.ibm.com>
Documentation/memory-hotplug.txt | 40 +++++++++++++++++++++++----------------
1 file changed, 24 insertions(+), 16 deletions(-)
--- linux-2.6.orig/Documentation/memory-hotplug.txt 2010-06-23 15:06:53.000000000 -0500
+++ linux-2.6/Documentation/memory-hotplug.txt 2010-07-19 21:00:11.000000000 -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
-(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 conatined 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.
-'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.
+'start_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.
These directories/files appear after physical memory hotplug phase.
More information about the Linuxppc-dev