The memory hotplug notifier description is about kernel internals rather
than admin/user visible API. Place it appropriately.
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/memory-hotplug.rst | 83 ---------------------
Documentation/core-api/index.rst | 2 +
Documentation/core-api/memory-hotplug-notifier.rst | 84 ++++++++++++++++++++++
3 files changed, 86 insertions(+), 83 deletions(-)
create mode 100644 Documentation/core-api/memory-hotplug-notifier.rst
diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
index a33090c..0b9c83e 100644
--- a/Documentation/admin-guide/mm/memory-hotplug.rst
+++ b/Documentation/admin-guide/mm/memory-hotplug.rst
@@ -31,7 +31,6 @@ be changed often.
6.1 Memory offline and ZONE_MOVABLE
6.2. How to offline memory
7. Physical memory remove
- 8. Memory hotplug event notifier
9. Future Work List
@@ -414,88 +413,6 @@ Need more implementation yet....
- Notification completion of remove works by OS to firmware.
- Guard from remove if not yet.
-Memory hotplug event notifier
-=============================
-
-Hotplugging events are sent to a notification queue.
-
-There are six types of notification defined in ``include/linux/memory.h``:
-
-MEM_GOING_ONLINE
- Generated before new memory becomes available in order to be able to
- prepare subsystems to handle memory. The page allocator is still unable
- to allocate from the new memory.
-
-MEM_CANCEL_ONLINE
- Generated if MEMORY_GOING_ONLINE fails.
-
-MEM_ONLINE
- Generated when memory has successfully brought online. The callback may
- allocate pages from the new memory.
-
-MEM_GOING_OFFLINE
- Generated to begin the process of offlining memory. Allocations are no
- longer possible from the memory but some of the memory to be offlined
- is still in use. The callback can be used to free memory known to a
- subsystem from the indicated memory block.
-
-MEM_CANCEL_OFFLINE
- Generated if MEMORY_GOING_OFFLINE fails. Memory is available again from
- the memory block that we attempted to offline.
-
-MEM_OFFLINE
- Generated after offlining memory is complete.
-
-A callback routine can be registered by calling::
-
- hotplug_memory_notifier(callback_func, priority)
-
-Callback functions with higher values of priority are called before callback
-functions with lower values.
-
-A callback function must have the following prototype::
-
- int callback_func(
- struct notifier_block *self, unsigned long action, void *arg);
-
-The first argument of the callback function (self) is a pointer to the block
-of the notifier chain that points to the callback function itself.
-The second argument (action) is one of the event types described above.
-The third argument (arg) passes a pointer of struct memory_notify::
-
- struct memory_notify {
- unsigned long start_pfn;
- unsigned long nr_pages;
- int status_change_nid_normal;
- int status_change_nid_high;
- int status_change_nid;
- }
-
-- start_pfn is start_pfn of online/offline memory.
-- nr_pages is # of pages of online/offline memory.
-- status_change_nid_normal is set node id when N_NORMAL_MEMORY of nodemask
- is (will be) set/clear, if this is -1, then nodemask status is not changed.
-- status_change_nid_high is set node id when N_HIGH_MEMORY of nodemask
- is (will be) set/clear, if this is -1, then nodemask status is not changed.
-- status_change_nid is set node id when N_MEMORY of nodemask is (will be)
- set/clear. It means a new(memoryless) node gets new memory by online and a
- node loses all memory. If this is -1, then nodemask status is not changed.
-
- If status_changed_nid* >= 0, callback should create/discard structures for the
- node if necessary.
-
-The callback routine shall return one of the values
-NOTIFY_DONE, NOTIFY_OK, NOTIFY_BAD, NOTIFY_STOP
-defined in ``include/linux/notifier.h``
-
-NOTIFY_DONE and NOTIFY_OK have no effect on the further processing.
-
-NOTIFY_BAD is used as response to the MEM_GOING_ONLINE, MEM_GOING_OFFLINE,
-MEM_ONLINE, or MEM_OFFLINE action to cancel hotplugging. It stops
-further processing of the notification queue.
-
-NOTIFY_STOP stops further processing of the notification queue.
-
Future Work
===========
diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst
index 165d7688..4f8a426 100644
--- a/Documentation/core-api/index.rst
+++ b/Documentation/core-api/index.rst
@@ -32,6 +32,8 @@ Core utilities
gfp_mask-from-fs-io
timekeeping
boot-time-mm
+ memory-hotplug-notifier
+
Interfaces for kernel debugging
===============================
diff --git a/Documentation/core-api/memory-hotplug-notifier.rst b/Documentation/core-api/memory-hotplug-notifier.rst
new file mode 100644
index 0000000..35347cc
--- /dev/null
+++ b/Documentation/core-api/memory-hotplug-notifier.rst
@@ -0,0 +1,84 @@
+.. _memory_hotplug_notifier:
+
+=============================
+Memory hotplug event notifier
+=============================
+
+Hotplugging events are sent to a notification queue.
+
+There are six types of notification defined in ``include/linux/memory.h``:
+
+MEM_GOING_ONLINE
+ Generated before new memory becomes available in order to be able to
+ prepare subsystems to handle memory. The page allocator is still unable
+ to allocate from the new memory.
+
+MEM_CANCEL_ONLINE
+ Generated if MEM_GOING_ONLINE fails.
+
+MEM_ONLINE
+ Generated when memory has successfully brought online. The callback may
+ allocate pages from the new memory.
+
+MEM_GOING_OFFLINE
+ Generated to begin the process of offlining memory. Allocations are no
+ longer possible from the memory but some of the memory to be offlined
+ is still in use. The callback can be used to free memory known to a
+ subsystem from the indicated memory block.
+
+MEM_CANCEL_OFFLINE
+ Generated if MEM_GOING_OFFLINE fails. Memory is available again from
+ the memory block that we attempted to offline.
+
+MEM_OFFLINE
+ Generated after offlining memory is complete.
+
+A callback routine can be registered by calling::
+
+ hotplug_memory_notifier(callback_func, priority)
+
+Callback functions with higher values of priority are called before callback
+functions with lower values.
+
+A callback function must have the following prototype::
+
+ int callback_func(
+ struct notifier_block *self, unsigned long action, void *arg);
+
+The first argument of the callback function (self) is a pointer to the block
+of the notifier chain that points to the callback function itself.
+The second argument (action) is one of the event types described above.
+The third argument (arg) passes a pointer of struct memory_notify::
+
+ struct memory_notify {
+ unsigned long start_pfn;
+ unsigned long nr_pages;
+ int status_change_nid_normal;
+ int status_change_nid_high;
+ int status_change_nid;
+ }
+
+- start_pfn is start_pfn of online/offline memory.
+- nr_pages is # of pages of online/offline memory.
+- status_change_nid_normal is set node id when N_NORMAL_MEMORY of nodemask
+ is (will be) set/clear, if this is -1, then nodemask status is not changed.
+- status_change_nid_high is set node id when N_HIGH_MEMORY of nodemask
+ is (will be) set/clear, if this is -1, then nodemask status is not changed.
+- status_change_nid is set node id when N_MEMORY of nodemask is (will be)
+ set/clear. It means a new(memoryless) node gets new memory by online and a
+ node loses all memory. If this is -1, then nodemask status is not changed.
+
+ If status_changed_nid* >= 0, callback should create/discard structures for the
+ node if necessary.
+
+The callback routine shall return one of the values
+NOTIFY_DONE, NOTIFY_OK, NOTIFY_BAD, NOTIFY_STOP
+defined in ``include/linux/notifier.h``
+
+NOTIFY_DONE and NOTIFY_OK have no effect on the further processing.
+
+NOTIFY_BAD is used as response to the MEM_GOING_ONLINE, MEM_GOING_OFFLINE,
+MEM_ONLINE, or MEM_OFFLINE action to cancel hotplugging. It stops
+further processing of the notification queue.
+
+NOTIFY_STOP stops further processing of the notification queue.
--
2.7.4
