This patch cleans up ZONE_DEVICE page refcounting. Quoting Matthew Wilcox, "it removes a ton of cruft from every call to put_page()" This work was originally done by Ralph Campbell and submitted as RFC. As of today, it has been ack by Theodore Ts'o / Darrick J. Wong, and reviewed by Christoph Hellwig. https://lore.kernel.org/linux-mm/20201001181715.17416-1-rcampbell@nvidia.com...
"MEMORY_DEVICE_COHERENT for CPU-accessible coherent device memory" patchset depends on this patchset. https://lore.kernel.org/linux-mm/20211012171247.2861-1-alex.sierra@amd.com/
Ralph Campbell (2): ext4/xfs: add page refcount helper mm: remove extra ZONE_DEVICE struct page refcount
arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +- drivers/gpu/drm/nouveau/nouveau_dmem.c | 2 +- fs/dax.c | 8 +-- fs/ext4/inode.c | 5 +- fs/fuse/dax.c | 4 +- fs/xfs/xfs_file.c | 4 +- include/linux/dax.h | 10 ++++ include/linux/memremap.h | 7 +-- include/linux/mm.h | 11 ---- lib/test_hmm.c | 2 +- mm/internal.h | 8 +++ mm/memcontrol.c | 6 +-- mm/memremap.c | 69 +++++++------------------- mm/migrate.c | 5 -- mm/page_alloc.c | 3 ++ mm/swap.c | 45 ++--------------- 16 files changed, 60 insertions(+), 131 deletions(-)