When working with hugetlbfs ptes (which are actually pmds) is not valid to directly use pte functions like pte_present() because the hardware bit layout of pmds and ptes can be different. This is the case on s390. Therefore we have to convert the hugetlbfs ptes first into a valid pte encoding with huge_ptep_get().
Currently the /proc/<pid>/numa_maps code uses hugetlbfs ptes without huge_ptep_get(). On s390 this leads to the following two problems: 1) The pte_present() function returns false (instead of true) for PROT_NONE hugetlb ptes. Therefore PROT_NONE vmas are missing completely in the "numa_maps" output. 2) The pte_dirty() function always returns false for all hugetlb ptes. Therefore these pages are reported as "mapped=xxx" instead of "dirty=xxx". Therefore use huge_ptep_get() to correctly convert the hugetlb ptes. Reviewed-by: Gerald Schaefer <[email protected]> Signed-off-by: Michael Holzheu <[email protected]> --- fs/proc/task_mmu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 85d16c6..4a0c31f 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1552,18 +1552,19 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr, static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask, unsigned long addr, unsigned long end, struct mm_walk *walk) { + pte_t huge_pte = huge_ptep_get(pte); struct numa_maps *md; struct page *page; - if (!pte_present(*pte)) + if (!pte_present(huge_pte)) return 0; - page = pte_page(*pte); + page = pte_page(huge_pte); if (!page) return 0; md = walk->private; - gather_stats(page, md, pte_dirty(*pte), 1); + gather_stats(page, md, pte_dirty(huge_pte), 1); return 0; } -- 2.3.9
