On 11/10/2018 06:58, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
>
> to allow additions of new documentation about memory hotplug under the same
> roof.
>
> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
> ---
> Documentation/core-api/index.rst | 2 +-
> Documentation/core-api/memory-hotplug-notifier.rst | 84 ---------------------
> Documentation/core-api/memory-hotplug.rst | 87 ++++++++++++++++++++++
> 3 files changed, 88 insertions(+), 85 deletions(-)
> delete mode 100644 Documentation/core-api/memory-hotplug-notifier.rst
> create mode 100644 Documentation/core-api/memory-hotplug.rst
>
> diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst
> index 4f8a426..29c790f 100644
> --- a/Documentation/core-api/index.rst
> +++ b/Documentation/core-api/index.rst
> @@ -32,7 +32,7 @@ Core utilities
> gfp_mask-from-fs-io
> timekeeping
> boot-time-mm
> - memory-hotplug-notifier
> + memory-hotplug
>
>
> Interfaces for kernel debugging
> diff --git a/Documentation/core-api/memory-hotplug-notifier.rst b/Documentation/core-api/memory-hotplug-notifier.rst
> deleted file mode 100644
> index 35347cc..0000000
> --- a/Documentation/core-api/memory-hotplug-notifier.rst
> +++ /dev/null
> @@ -1,84 +0,0 @@
> -.. _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.
> diff --git a/Documentation/core-api/memory-hotplug.rst b/Documentation/core-api/memory-hotplug.rst
> new file mode 100644
> index 0000000..a99f2f2
> --- /dev/null
> +++ b/Documentation/core-api/memory-hotplug.rst
> @@ -0,0 +1,87 @@
> +.. _memory_hotplug:
> +
> +==============
> +Memory hotplug
> +==============
> +
> +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.
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
