From 52d7e21fd5677829353f7490723adf5f61999d84 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Thu, 11 Oct 2018 07:58:16 +0300 Subject: docs/core-api: rename memory-hotplug-notifier to memory-hotplug to allow additions of new documentation about memory hotplug under the same roof. Signed-off-by: Mike Rapoport Reviewed-by: David Hildenbrand Signed-off-by: Jonathan Corbet --- 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 (limited to 'Documentation/core-api') diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst index 4f8a4266eb7c..29c790f571a5 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 35347cc3a43a..000000000000 --- 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 000000000000..a99f2f264725 --- /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. -- cgit v1.2.3