[RFC,0/3] mm/memory_hotplug: Factor out memory block device handling

Message

David Hildenbrand April 8, 2019, 10:12 a.m. UTC

We only want memory block devices for memory to be onlined/offlined
(add/remove from the buddy). This is required so user space can
online/offline memory and kdump gets notified about newly onlined memory.

Only such memory has the requirement of having to span whole memory blocks.
Let's factor out creation/removal of memory block devices.

This not only allows to clean up arch_add_memory() to get rid of
want_memblock, but also reduces locking overhead and eventually allows
us to handle errors while adding memory in a nicer fashion.

Only did a quick sanity test with DIMM plug/unplug. This should be
sufficient to discuss the general approach. Patches are against
next/master.

David Hildenbrand (3):
  mm/memory_hotplug: Simplify and fix check_hotplug_memory_range()
  mm/memory_hotplug: Create memory block devices after arch_add_memory()
  mm/memory_hotplug: Remove memory block devices before
    arch_remove_memory()

 drivers/base/memory.c  | 108 +++++++++++++++++++++--------------------
 drivers/base/node.c    |   7 ++-
 include/linux/memory.h |   4 +-
 include/linux/node.h   |   6 +--
 mm/memory_hotplug.c    |  38 +++++++--------
 5 files changed, 81 insertions(+), 82 deletions(-)