Currently, virtio-mem does not really support ZONE_MOVABLE. While it allows
to online fully plugged memory blocks to ZONE_MOVABLE, it does not allow
to online partially-plugged memory blocks to ZONE_MOVABLE and will never
consider such memory blocks when unplugging memory. This might be
surprising for users (especially, if onlining suddenly fails).
Let's support partially plugged memory blocks in ZONE_MOVABLE, allowing
partially plugged memory blocks to be online to ZONE_MOVABLE and also
unplugging from such memory blocks.
This is especially helpful for testing, but also paves the way for
virtio-mem optimizations, allowing more memory to get reliably unplugged.
Cleanup has_unmovable_pages() and set_migratetype_isolate(), providing
better documentation of how ZONE_MOVABLE interacts with different kind of
unmovable pages (memory offlining vs. alloc_contig_range()).
David Hildenbrand (6):
mm/page_alloc: tweak comments in has_unmovable_pages()
mm/page_isolation: don't dump_page(NULL) in set_migratetype_isolate()
mm/page_isolation: drop WARN_ON_ONCE() in set_migratetype_isolate()
mm/page_isolation: cleanup set_migratetype_isolate()
mm/page_alloc: restrict ZONE_MOVABLE optimization in
has_unmovable_pages() to memory offlining
virtio-mem: don't special-case ZONE_MOVABLE
drivers/virtio/virtio_mem.c | 47 +++++++------------------------------
mm/page_alloc.c | 29 +++++++++--------------
mm/page_isolation.c | 40 ++++++++++++++-----------------
3 files changed, 36 insertions(+), 80 deletions(-)
--
2.26.2
