Testing the latest linux git tree turned up a few bugs with page migration to and from ZONE_DEVICE private and anonymous pages. Hopefully this series clarifies how ZONE_DEVICE private struct page uses the same mapping and index fields from the source anonymous page mapping. Changes from v2 to v3: Patch #1 is basically new (like v1 but with comments from v2) to accommodate Matthew Wilcox's NAK of v2 and Christoph's objection to adding _zd_pad fields in v1. Patch #2 adds reviewed-by Patch #3 adds comments explaining the reason for setting "subpage". Changes from v1 to v2: Patch #1 merges ZONE_DEVICE page struct into a union of lru and a struct for ZONE_DEVICE fields. So, basically a new patch. Patch #2 updates the code comments for clearing page->mapping as suggested by John Hubbard. Patch #3 is unchanged from the previous posting but note that Andrew Morton has v1 queued in v5.2-mmotm-2019-07-18-16-08. Ralph Campbell (3): mm: document zone device struct page reserved fields mm/hmm: fix ZONE_DEVICE anon page mapping reuse mm/hmm: Fix bad subpage pointer in try_to_unmap_one include/linux/mm_types.h | 9 ++++++++- kernel/memremap.c | 4 ++++ mm/rmap.c | 1 + 3 files changed, 13 insertions(+), 1 deletion(-) -- 2.20.1
