2022-11-09 09:15:00

by Baolin Wang

Subject: [PATCH] Revert "mm: migration: fix the FOLL_GET failure on following huge page"

Revert commit 831568214883 ("mm: migration: fix the FOLL_GET failure on
following huge page"), since after commit 1a6baaa0db73 ("s390/hugetlb:
switch to generic version of follow_huge_pud()") and commit 57a196a58421
("hugetlb: simplify hugetlb handling in follow_page_mask") were merged,
now all the following huge page routines can support FOLL_GET operation.

Signed-off-by: Baolin Wang <[email protected]>
---
mm/migrate.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 1317e5c..53af072 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1908,7 +1908,6 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,

for (i = 0; i < nr_pages; i++) {
unsigned long addr = (unsigned long)(*pages);
- unsigned int foll_flags = FOLL_DUMP;
struct vm_area_struct *vma;
struct page *page;
int err = -EFAULT;
@@ -1917,12 +1916,8 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
if (!vma)
goto set_status;

- /* Not all huge page follow APIs support 'FOLL_GET' */
- if (!is_vm_hugetlb_page(vma))
- foll_flags |= FOLL_GET;
-
/* FOLL_DUMP to ignore special (like zero) pages */
- page = follow_page(vma, addr, foll_flags);
+ page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);

err = PTR_ERR(page);
if (IS_ERR(page))
@@ -1935,8 +1930,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
if (!is_zone_device_page(page))
err = page_to_nid(page);

- if (foll_flags & FOLL_GET)
- put_page(page);
+ put_page(page);
set_status:
*status = err;

--
1.8.3.1

2022-11-09 11:50:21

by Wang, Haiyue

Subject: RE: [PATCH] Revert "mm: migration: fix the FOLL_GET failure on following huge page"

> -----Original Message-----
> From: Baolin Wang <[email protected]>
> Sent: Wednesday, November 9, 2022 16:40
> To: [email protected]
> Cc: Wang, Haiyue <[email protected]>; Huang, Ying <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected]; linux-
> [email protected]
> Subject: [PATCH] Revert "mm: migration: fix the FOLL_GET failure on following huge page"
>
> Revert commit 831568214883 ("mm: migration: fix the FOLL_GET failure on
> following huge page"), since after commit 1a6baaa0db73 ("s390/hugetlb:
> switch to generic version of follow_huge_pud()") and commit 57a196a58421
> ("hugetlb: simplify hugetlb handling in follow_page_mask") were merged,
> now all the following huge page routines can support FOLL_GET operation.
>
> Signed-off-by: Baolin Wang <[email protected]>
> ---

Cool, thanks, my ugly code is gone. ;-)

Acked-by: Haiyue Wang <[email protected]>

> mm/migrate.c | 10 ++--------
> 1 file changed, 2 insertions(+), 8 deletions(-)
>
> --
> 1.8.3.1