docs/vm: split memory hotplug notifier description to Documentation/core-api

The memory hotplug notifier description is about kernel internals rather
than admin/user visible API. Place it appropriately.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 83 deletions

diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
index a33090c179d6..0b9c83effaa4 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
 ===========