[v1,00/11] mm/memory_hotplug: online_pages()/offline_pages() cleanups

Message

David Hildenbrand Aug. 19, 2020, 10:11 a.m. UTC

These are a bunch of cleanups for online_pages()/offline_pages() and
related code, mostly getting rid of memory hole handling that is no longer
necessary. There is only a single walk_system_ram_range() call left in
offline_pages(), to make sure we don't have any memory holes. I had some
of these patches lying around for a longer time but didn't have time to
polish them.

In addition, the last patch marks all pageblocks of memory to get onlined
MIGRATE_ISOLATE, so pages that have just been exposed to the buddy cannot
get allocated before onlining is complete. Once heavy lifting is done,
the pageblocks are set to MIGRATE_MOVABLE, such that allocations are
possible.

I played with DIMMs and virtio-mem on x86-64 and didn't spot any surprises.
I verified that the numer of isolated pageblocks is correctly handled when
onlining/offlining.

David Hildenbrand (11):
  mm/memory_hotplug: inline __offline_pages() into offline_pages()
  mm/memory_hotplug: enforce section granularity when onlining/offlining
  mm/memory_hotplug: simplify checking if all pages are isolated in
    offline_pages()
  mm/memory_hotplug: simplify offlining of pages in offline_pages()
  mm/page_alloc: simplify __offline_isolated_pages()
  mm/memory_hotplug: drop nr_isolate_pageblock in offline_pages()
  mm/page_isolation: simplify return value of start_isolate_page_range()
  mm/memory_hotplug: simplify page onlining
  mm/page_alloc: drop stale pageblock comment in memmap_init_zone*()
  mm: pass migratetype into memmap_init_zone() and
    move_pfn_range_to_zone()
  mm/memory_hotplug: mark pageblocks MIGRATE_ISOLATE while onlining
    memory

 arch/ia64/mm/init.c            |   4 +-
 include/linux/memory_hotplug.h |   7 +-
 include/linux/mm.h             |   3 +-
 mm/Kconfig                     |   2 +-
 mm/memory_hotplug.c            | 156 ++++++++++++++-------------------
 mm/memremap.c                  |   3 +-
 mm/page_alloc.c                |  64 ++++----------
 mm/page_isolation.c            |   7 +-
 8 files changed, 98 insertions(+), 148 deletions(-)