diff mbox series

[v2,2/4] mm/fork: Pass new vma pointer into copy_page_range()

Message ID 20200925222600.6832-3-peterx@redhat.com (mailing list archive)
State New, archived
Headers show
Series mm: Break COW for pinned pages during fork() | expand

Commit Message

Peter Xu Sept. 25, 2020, 10:25 p.m. UTC 
This prepares for the future work to trigger early cow on pinned pages during
fork().  No functional change intended.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/linux/mm.h |  2 +-
 kernel/fork.c      |  2 +-
 mm/memory.c        | 14 +++++++++-----
 3 files changed, 11 insertions(+), 7 deletions(-)

Comments

Kirill A . Shutemov Sept. 30, 2020, 1:30 p.m. UTC | #1 
On Fri, Sep 25, 2020 at 06:25:58PM -0400, Peter Xu wrote:
> This prepares for the future work to trigger early cow on pinned pages during
> fork().  No functional change intended.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  include/linux/mm.h |  2 +-
>  kernel/fork.c      |  2 +-
>  mm/memory.c        | 14 +++++++++-----
>  3 files changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index b2f370f0b420..ae914be004b3 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1646,7 +1646,7 @@ struct mmu_notifier_range;
>  void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
>  		unsigned long end, unsigned long floor, unsigned long ceiling);
>  int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
> -			struct vm_area_struct *vma);
> +		    struct vm_area_struct *vma, struct vm_area_struct *new);

It makes dst/src mm_struct arguments redundant. There's always vma->vm_mm.
Peter Xu Sept. 30, 2020, 5:05 p.m. UTC | #2 
On Wed, Sep 30, 2020 at 04:30:55PM +0300, Kirill A. Shutemov wrote:
> >  int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
> > -			struct vm_area_struct *vma);
> > +		    struct vm_area_struct *vma, struct vm_area_struct *new);
> 
> It makes dst/src mm_struct arguments redundant. There's always vma->vm_mm.

Indeed.  I'll post a patch later for it.  Thanks.
diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index b2f370f0b420..ae914be004b3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1646,7 +1646,7 @@  struct mmu_notifier_range;
 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 		unsigned long end, unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
-			struct vm_area_struct *vma);
+		    struct vm_area_struct *vma, struct vm_area_struct *new);
 int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
 		   struct mmu_notifier_range *range,
 		   pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
diff --git a/kernel/fork.c b/kernel/fork.c
index e65d8192d080..da8d360fb032 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -589,7 +589,7 @@  static __latent_entropy int dup_mmap(struct mm_struct *mm,
 
 		mm->map_count++;
 		if (!(tmp->vm_flags & VM_WIPEONFORK))
-			retval = copy_page_range(mm, oldmm, mpnt);
+			retval = copy_page_range(mm, oldmm, mpnt, tmp);
 
 		if (tmp->vm_ops && tmp->vm_ops->open)
 			tmp->vm_ops->open(tmp);
diff --git a/mm/memory.c b/mm/memory.c
index e315b1f1ef08..4c56d7b92b0e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -819,6 +819,7 @@  copy_present_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 
 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		   pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
+		   struct vm_area_struct *new,
 		   unsigned long addr, unsigned long end)
 {
 	pte_t *orig_src_pte, *orig_dst_pte;
@@ -889,6 +890,7 @@  static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 
 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
+		struct vm_area_struct *new,
 		unsigned long addr, unsigned long end)
 {
 	pmd_t *src_pmd, *dst_pmd;
@@ -915,7 +917,7 @@  static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src
 		if (pmd_none_or_clear_bad(src_pmd))
 			continue;
 		if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
-						vma, addr, next))
+				   vma, new, addr, next))
 			return -ENOMEM;
 	} while (dst_pmd++, src_pmd++, addr = next, addr != end);
 	return 0;
@@ -923,6 +925,7 @@  static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src
 
 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		p4d_t *dst_p4d, p4d_t *src_p4d, struct vm_area_struct *vma,
+		struct vm_area_struct *new,
 		unsigned long addr, unsigned long end)
 {
 	pud_t *src_pud, *dst_pud;
@@ -949,7 +952,7 @@  static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src
 		if (pud_none_or_clear_bad(src_pud))
 			continue;
 		if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
-						vma, addr, next))
+				   vma, new, addr, next))
 			return -ENOMEM;
 	} while (dst_pud++, src_pud++, addr = next, addr != end);
 	return 0;
@@ -957,6 +960,7 @@  static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src
 
 static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
+		struct vm_area_struct *new,
 		unsigned long addr, unsigned long end)
 {
 	p4d_t *src_p4d, *dst_p4d;
@@ -971,14 +975,14 @@  static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src
 		if (p4d_none_or_clear_bad(src_p4d))
 			continue;
 		if (copy_pud_range(dst_mm, src_mm, dst_p4d, src_p4d,
-						vma, addr, next))
+				   vma, new, addr, next))
 			return -ENOMEM;
 	} while (dst_p4d++, src_p4d++, addr = next, addr != end);
 	return 0;
 }
 
 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
-		struct vm_area_struct *vma)
+		    struct vm_area_struct *vma, struct vm_area_struct *new)
 {
 	pgd_t *src_pgd, *dst_pgd;
 	unsigned long next;
@@ -1033,7 +1037,7 @@  int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		if (pgd_none_or_clear_bad(src_pgd))
 			continue;
 		if (unlikely(copy_p4d_range(dst_mm, src_mm, dst_pgd, src_pgd,
-					    vma, addr, next))) {
+					    vma, new, addr, next))) {
 			ret = -ENOMEM;
 			break;
 		}