From: Nathan Fontenot <nfont@austin.ibm.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org
Cc: Greg KH <greg@kroah.com>,
steiner@sgi.com, Robin Holt <holt@sgi.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Dave Hansen <dave@linux.vnet.ibm.com>
Subject: [PATCH 9/9] v3 Update memory hotplug documentation
Date: Fri, 01 Oct 2010 13:37:49 -0500 [thread overview]
Message-ID: <4CA62A7D.8030905@austin.ibm.com> (raw)
In-Reply-To: <4CA62700.7010809@austin.ibm.com>
Update the memory hotplug documentation to reflect the new behaviors of
memory blocks reflected in sysfs.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
---
Documentation/memory-hotplug.txt | 47 +++++++++++++++++++++++++--------------
1 file changed, 31 insertions(+), 16 deletions(-)
Index: linux-next/Documentation/memory-hotplug.txt
===================================================================
--- linux-next.orig/Documentation/memory-hotplug.txt 2010-09-29 14:56:24.000000000 -0500
+++ linux-next/Documentation/memory-hotplug.txt 2010-09-30 14:59:47.000000000 -0500
@@ -126,36 +126,51 @@
--------------------------------
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. The files 'phys_index' and
+'end_phys_index' under each directory report the beginning and end section id's
+for the memory block covered by the sysfs directory. It is expected that all
+memory sections in this range are present and no memory holes exist in the
+range. Currently there is no way to determine if there is a memory hole, but
+the existence of one should not affect the hotplug capabilities of 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 4 or 5 files, the end_phys_index file being
+a recent addition and not present on older kernels.
-/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.
next prev parent reply other threads:[~2010-10-01 18:37 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-01 18:22 [PATCH 0/9] v3 De-couple sysfs memory directories from memory sections Nathan Fontenot
2010-10-01 18:28 ` [PATCH 1/9] v3 Move find_memory_block routine Nathan Fontenot
2010-10-01 18:40 ` Robin Holt
2010-10-05 5:01 ` KAMEZAWA Hiroyuki
2010-10-01 18:29 ` [PATCH 2/9] v3 Add mutex for adding/removing memory blocks Nathan Fontenot
2010-10-01 18:45 ` Robin Holt
2010-10-05 5:06 ` KAMEZAWA Hiroyuki
2010-10-01 18:30 ` [PATCH 3/9] v3 Add section count to memory_block struct Nathan Fontenot
2010-10-01 18:46 ` Robin Holt
2010-10-05 5:08 ` KAMEZAWA Hiroyuki
2010-10-01 18:31 ` [PATCH 4/9] v3 Allow memory blocks to span multiple memory sections Nathan Fontenot
2010-10-01 18:52 ` Robin Holt
2010-10-01 18:56 ` Nathan Fontenot
2010-10-01 19:00 ` Nathan Fontenot
2010-10-01 19:20 ` Robin Holt
2010-10-05 5:13 ` KAMEZAWA Hiroyuki
2010-10-01 18:33 ` [PATCH 5/9] v3 rename phys_index properties of memory block struct Nathan Fontenot
2010-10-01 18:54 ` Robin Holt
2010-10-05 5:14 ` KAMEZAWA Hiroyuki
2010-10-01 18:34 ` [PATCH 6/9] v3 Update node sysfs code Nathan Fontenot
2010-10-01 18:55 ` Robin Holt
2010-10-05 5:15 ` KAMEZAWA Hiroyuki
2010-10-01 18:35 ` [PATCH 7/9] v3 Define memory_block_size_bytes for powerpc/pseries Nathan Fontenot
2010-10-01 18:56 ` Robin Holt
2010-10-03 17:55 ` Balbir Singh
2010-10-03 18:07 ` Robin Holt
2010-10-03 18:11 ` Dave Hansen
2010-10-03 18:27 ` Balbir Singh
2010-10-04 14:45 ` Nathan Fontenot
2010-10-01 18:37 ` [PATCH 8/9] v3 Define memory_block_size_bytes for x86_64 with CONFIG_X86_UV set Nathan Fontenot
2010-10-01 18:57 ` Robin Holt
2010-10-01 18:37 ` Nathan Fontenot [this message]
2010-10-01 18:58 ` [PATCH 9/9] v3 Update memory hotplug documentation Robin Holt
2010-10-05 5:18 ` KAMEZAWA Hiroyuki
2010-10-21 12:05 ` [PATCH 0/9] v3 De-couple sysfs memory directories from memory sections Nikanth Karthikesan
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