On architectures that support hugepages composed of contiguous pte as well as block entries at the same level in the page table, huge_pte_offset() is not able to determine the right offset to return when it encounters a swap entry (which is used to mark poisoned as well as migrated pages in the page table).
huge_pte_offset() needs to know the size of the hugepage at the requested address to determine the offset to return - the current entry or the first entry of a set of contiguous hugepages. This came up while enabling support for memory failure handling on arm64[0]. Patch 1 adds a hstate parameter to huge_pte_offset() to provide additional information about the target address. It also updates the signatures (and usage) of huge_pte_offset() for architectures that override the generic implementation. This patch has been compile tested on ia64 and x86. Patch 2 uses the size determined by the parameter added in Patch 1, to return the correct page table offset. The patchset is based on top of v4.11-rc3 and the arm64 huge page cleanup for break-before-make[1]. Thanks, Punit [0] http://marc.info/?l=linux-arm-kernel&m=148772028907925&w=2 [1] https://www.spinics.net/lists/arm-kernel/msg570422.html Punit Agrawal (2): mm/hugetlb.c: add hstate parameter to huge_pte_offset() arm64: hugetlbpages: Correctly handle swap entries in huge_pte_offset() arch/arm64/mm/hugetlbpage.c | 33 +++++++++++++++++---------------- arch/ia64/mm/hugetlbpage.c | 4 ++-- arch/metag/mm/hugetlbpage.c | 2 +- arch/mips/mm/hugetlbpage.c | 2 +- arch/parisc/mm/hugetlbpage.c | 2 +- arch/powerpc/mm/hugetlbpage.c | 2 +- arch/s390/mm/hugetlbpage.c | 2 +- arch/sh/mm/hugetlbpage.c | 2 +- arch/sparc/mm/hugetlbpage.c | 2 +- arch/tile/mm/hugetlbpage.c | 2 +- arch/x86/mm/hugetlbpage.c | 2 +- fs/userfaultfd.c | 7 +++++-- include/linux/hugetlb.h | 2 +- mm/hugetlb.c | 18 +++++++++--------- mm/page_vma_mapped.c | 2 +- mm/pagewalk.c | 2 +- 16 files changed, 45 insertions(+), 41 deletions(-) -- 2.11.0
