[PATCH v1 0/6] mm / virtio-mem: support ZONE_MOVABLE

David Hildenbrand
2020-06-30T14:26:57Z

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(-)

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2.26.2