This is agains mm/mm-unstable, but everything except patch #7 and #8 should apply on current master. Especially patch #1 and #2 should go upstream first, so we can let the other stuff mature a bit longer.
Next attempt to handle the fallout of 474098edac26 ("mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()") where I accidentially missed that follow_page() and smaps implicitly kept the FOLL_NUMA flag clear by not setting it if FOLL_FORCE is absent, to not trigger faults on PROT_NONE-mapped PTEs.
Patch #1 fixes the known issues by reintroducing FOLL_NUMA as FOLL_HONOR_NUMA_FAULT and decoupling it from FOLL_FORCE.
Patch #2 is a cleanup that I think actually fixes some corner cases, so I added a Fixes: tag.
Patch #3 makes KVM explicitly set FOLL_HONOR_NUMA_FAULT in the single case where it is required, and documents the situation.
Patch #4 then stops implicitly setting FOLL_HONOR_NUMA_FAULT. But note that for FOLL_WRITE we always implicitly honor NUMA hinting faults.
Patch #5 and patch #6 cleanup some comments.
Patch #7 improves the KVM functional tests such that patch #8 can actually check for one of the known issues: KSM no longer working on PROT_NONE mappings on x86-64 with CONFIG_NUMA_BALANCING.
Cc: Andrew Morton akpm@linux-foundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: liubo liubo254@huawei.com Cc: Peter Xu peterx@redhat.com Cc: Matthew Wilcox willy@infradead.org Cc: Hugh Dickins hughd@google.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: John Hubbard jhubbard@nvidia.com Cc: Mel Gorman mgorman@suse.de Cc: Shuah Khan shuah@kernel.org Cc: Paolo Bonzini pbonzini@redhat.com
David Hildenbrand (8): mm/gup: reintroduce FOLL_NUMA as FOLL_HONOR_NUMA_FAULT smaps: use vm_normal_page_pmd() instead of follow_trans_huge_pmd() kvm: explicitly set FOLL_HONOR_NUMA_FAULT in hva_to_pfn_slow() mm/gup: don't implicitly set FOLL_HONOR_NUMA_FAULT pgtable: improve pte_protnone() comment mm/huge_memory: remove stale NUMA hinting comment from follow_trans_huge_pmd() selftest/mm: ksm_functional_tests: test in mmap_and_merge_range() if anything got merged selftest/mm: ksm_functional_tests: Add PROT_NONE test
fs/proc/task_mmu.c | 3 +- include/linux/mm.h | 21 +++- include/linux/mm_types.h | 9 ++ include/linux/pgtable.h | 16 ++- mm/gup.c | 23 +++- mm/huge_memory.c | 3 +- .../selftests/mm/ksm_functional_tests.c | 106 ++++++++++++++++-- virt/kvm/kvm_main.c | 13 ++- 8 files changed, 164 insertions(+), 30 deletions(-)