[PATCH 07/10] huge mm: move_huge_pmd does not need new_vma

Hugh Dickins
2016-04-05T20:51:18Z

Remove move_huge_pmd()'s redundant new_vma arg: all it was used for was
a VM_NOHUGEPAGE check on new_vma flags, but the new_vma is cloned from
the old vma, so a trans_huge_pmd in the new_vma will be as acceptable
as it was in the old vma, alignment and size permitting.

Signed-off-by: Hugh Dickins <hughd@google.com>
---
include/linux/huge_mm.h | 4 +---
mm/huge_memory.c | 7 ++-----
mm/mremap.c | 5 ++---
3 files changed, 5 insertions(+), 11 deletions(-)

--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -28,9 +28,7 @@ extern int zap_huge_pmd(struct mmu_gathe
extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
unsigned char *vec);
-extern bool move_huge_pmd(struct vm_area_struct *vma,
- struct vm_area_struct *new_vma,
- unsigned long old_addr,
+extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
unsigned long new_addr, unsigned long old_end,
pmd_t *old_pmd, pmd_t *new_pmd);
extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1704,20 +1704,17 @@ int zap_huge_pmd(struct mmu_gather *tlb,
return 1;
}

-bool move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
- unsigned long old_addr,
+bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
unsigned long new_addr, unsigned long old_end,
pmd_t *old_pmd, pmd_t *new_pmd)
{
spinlock_t *old_ptl, *new_ptl;
pmd_t pmd;
-
struct mm_struct *mm = vma->vm_mm;

if ((old_addr & ~HPAGE_PMD_MASK) ||
(new_addr & ~HPAGE_PMD_MASK) ||
- old_end - old_addr < HPAGE_PMD_SIZE ||
- (new_vma->vm_flags & VM_NOHUGEPAGE))
+ old_end - old_addr < HPAGE_PMD_SIZE)
return false;

/*
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -198,9 +198,8 @@ unsigned long move_page_tables(struct vm
/* See comment in move_ptes() */
if (need_rmap_locks)
anon_vma_lock_write(vma->anon_vma);
- moved = move_huge_pmd(vma, new_vma, old_addr,
- new_addr, old_end,
- old_pmd, new_pmd);
+ moved = move_huge_pmd(vma, old_addr, new_addr,
+ old_end, old_pmd, new_pmd);
if (need_rmap_locks)
anon_vma_unlock_write(vma->anon_vma);
if (moved) {