linux.git/Documentation/core-api/memory-hotplug.rst, branch v6.18.21

mm,memory_hotplug: drop status_change_nid parameter from memory_notify

2025-07-13T23:38:17+00:00

There no users left of status_change_nid, so drop it from memory_notify
struct.

Link: https://lkml.kernel.org/r/20250616135158.450136-12-osalvador@suse.de
Signed-off-by: Oscar Salvador 
Suggested-by: David Hildenbrand 
Acked-by: David Hildenbrand 
Reviewed-by: Vlastimil Babka 
Cc: Harry Yoo 
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joanthan Cameron 
Cc: Rakie Kim 
Signed-off-by: Andrew Morton

mm,memory_hotplug: implement numa node notifier

2025-07-13T23:38:15+00:00

There are at least six consumers of hotplug_memory_notifier that what they
really are interested in is whether any numa node changed its state, e.g:
going from having memory to not having memory and vice versa.

Implement a specific notifier for numa nodes when their state gets
changed, which will later be used by those consumers that are only
interested in numa node state changes.

Add documentation as well.

[dan.carpenter@linaro.org: set failure reason in offline_pages()]
  Link: https://lkml.kernel.org/r/be4fd31b-7d09-46b0-8329-6d0464ffa7a5@sabinyo.mountain
Link: https://lkml.kernel.org/r/20250616135158.450136-4-osalvador@suse.de
Signed-off-by: Oscar Salvador 
Signed-off-by: Dan Carpenter 
Reviewed-by: Jonathan Cameron 
Reviewed-by: Harry Yoo 
Reviewed-by: Vlastimil Babka 
Acked-by: David Hildenbrand 
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Rakie Kim 
Signed-off-by: Andrew Morton

mm,memory_hotplug: remove status_change_nid_normal and update documentation

2025-07-13T23:38:14+00:00

Now that the last user of status_change_nid_normal is gone, we can remove
it.  Update documentation accordingly.

Link: https://lkml.kernel.org/r/20250616135158.450136-3-osalvador@suse.de
Signed-off-by: Oscar Salvador 
Reviewed-by: Vlastimil Babka 
Acked-by: David Hildenbrand 
Cc: Harry Yoo 
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joanthan Cameron 
Cc: Rakie Kim 
Signed-off-by: Andrew Morton

mm/memory_hotplug: remove HIGHMEM leftovers

2021-11-06T20:30:42+00:00

We don't support CONFIG_MEMORY_HOTPLUG on 32 bit and consequently not
HIGHMEM.  Let's remove any leftover code -- including the unused
"status_change_nid_high" field part of the memory notifier.

Link: https://lkml.kernel.org/r/20210929143600.49379-5-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Oscar Salvador 
Cc: Alex Shi 
Cc: Andy Lutomirski 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: Greg Kroah-Hartman 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Jason Wang 
Cc: Jonathan Corbet 
Cc: Michael Ellerman 
Cc: "Michael S. Tsirkin" 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: "Rafael J. Wysocki" 
Cc: Shuah Khan 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

docs/core-api: memory-hotplug: add some details about locking internals

2018-10-12T17:14:19+00:00

Let's document the magic a bit, especially why device_hotplug_lock is
required when adding/removing memory and how it all play together with
requests to online/offline memory from user space.

[ rppt: moved the text to Documentation/core-api/memory-hotplug.rst ]

Link: http://lkml.kernel.org/r/20180925091457.28651-7-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Pavel Tatashin 
Reviewed-by: Rashmica Gupta 
Cc: Jonathan Corbet 
Cc: Michal Hocko 
Cc: Balbir Singh 
Cc: Benjamin Herrenschmidt 
Cc: Boris Ostrovsky 
Cc: Dan Williams 
Cc: Greg Kroah-Hartman 
Cc: Haiyang Zhang 
Cc: Heiko Carstens 
Cc: John Allen 
Cc: Joonsoo Kim 
Cc: Juergen Gross 
Cc: Kate Stewart 
Cc: "K. Y. Srinivasan" 
Cc: Len Brown 
Cc: Martin Schwidefsky 
Cc: Mathieu Malaterre 
Cc: Michael Ellerman 
Cc: Michael Neuling 
Cc: Nathan Fontenot 
Cc: Oscar Salvador 
Cc: Paul Mackerras 
Cc: Philippe Ombredanne 
Cc: Rafael J. Wysocki 
Cc: "Rafael J. Wysocki" 
Cc: Stephen Hemminger 
Cc: Thomas Gleixner 
Cc: Vlastimil Babka 
Cc: YASUAKI ISHIMATSU 
Signed-off-by: Andrew Morton 
Signed-off-by: Mike Rapoport 
Signed-off-by: Jonathan Corbet

docs/core-api: rename memory-hotplug-notifier to memory-hotplug

2018-10-12T17:13:57+00:00

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