The move_pages() syscall can be used to find the numa node where a page currently resides. This is not working for device public memory pages, which erroneously report -EFAULT (unmapped or zero page).
Enable by adding a FOLL_DEVICE flag for follow_page(), which move_pages() will use. This could be done unconditionally, but adding a flag seems like a safer change. Cc: Jérôme Glisse <[email protected]> Signed-off-by: Reza Arbab <[email protected]> --- include/linux/mm.h | 1 + mm/gup.c | 2 +- mm/migrate.c | 2 +- 3 files changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index f8c10d3..783cb57 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2368,6 +2368,7 @@ static inline struct page *follow_page(struct vm_area_struct *vma, #define FOLL_MLOCK 0x1000 /* lock present pages */ #define FOLL_REMOTE 0x2000 /* we are working on non-current tsk/mm */ #define FOLL_COW 0x4000 /* internal GUP flag */ +#define FOLL_DEVICE 0x8000 /* return device pages */ static inline int vm_fault_to_errno(int vm_fault, int foll_flags) { diff --git a/mm/gup.c b/mm/gup.c index b2b4d42..6fbad70 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -110,7 +110,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, return NULL; } - page = vm_normal_page(vma, address, pte); + page = _vm_normal_page(vma, address, pte, flags & FOLL_DEVICE); if (!page && pte_devmap(pte) && (flags & FOLL_GET)) { /* * Only return device mapping pages in the FOLL_GET case since diff --git a/mm/migrate.c b/mm/migrate.c index 6954c14..dea0ceb 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1690,7 +1690,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, goto set_status; /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_DUMP); + page = follow_page(vma, addr, FOLL_DUMP | FOLL_DEVICE); err = PTR_ERR(page); if (IS_ERR(page)) -- 1.8.3.1
