Changes since v3 [1]: - Switch to "if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))" (David) - Finish collecting reviewed-bys across all patches in the series - Drop the libnvdimm fixup, to be merged through nvdimm.git not -mm [1]: http://lore.kernel.org/r/161052331545.1805594.2356512831689786960.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx --- Andrew, All patches in this series have been reviewed and the kbuild-robot reports a build-success over 172 configs. They pass an updated version of the nvdimm unit tests to exercise corner cases of pfn_to_online_page() and get_dev_pagemap() [2], and apply cleanly to current -next. Please apply, thanks. [2]: http://lore.kernel.org/r/161052209289.1804207.11599120961607513911.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx --- Michal reminds that the discussion about how to ensure pfn-walkers do not get confused by ZONE_DEVICE pages never resolved. A pfn-walker that uses pfn_to_online_page() may inadvertently translate a pfn as online and in the page allocator, when it is offline managed by a ZONE_DEVICE mapping (details in Patch 3: ("mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions")). The 2 proposals under consideration are teach pfn_to_online_page() to be precise in the presence of mixed-zone sections, or teach the memory-add code to drop the System RAM associated with ZONE_DEVICE collisions. In order to not regress memory capacity by a few 10s to 100s of MiB the approach taken in this set is to add precision to pfn_to_online_page(). In the course of validating pfn_to_online_page() a couple other fixes fell out: 1/ soft_offline_page() fails to drop the reference taken in the madvise(..., MADV_SOFT_OFFLINE) case. 2/ memory_failure() uses get_dev_pagemap() to lookup ZONE_DEVICE pages, however that mapping may contain data pages and metadata raw pfns. Introduce pgmap_pfn_valid() to delineate the 2 types and fail the handling of raw metadata pfns. --- Dan Williams (5): mm: Move pfn_to_online_page() out of line mm: Teach pfn_to_online_page() to consider subsection validity mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions mm: Fix page reference leak in soft_offline_page() mm: Fix memory_failure() handling of dax-namespace metadata include/linux/memory_hotplug.h | 17 +--------- include/linux/memremap.h | 6 +++ include/linux/mmzone.h | 22 +++++++++---- mm/memory-failure.c | 26 +++++++++++++-- mm/memory_hotplug.c | 69 ++++++++++++++++++++++++++++++++++++++++ mm/memremap.c | 15 +++++++++ 6 files changed, 128 insertions(+), 27 deletions(-)
