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SubjectRe: [PATCH v4 56/66] mm/mlock: Use maple tree iterators instead of vma linked list
On 12/1/21 15:30, Liam Howlett wrote:
> From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
> ---
> mm/mlock.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/mm/mlock.c b/mm/mlock.c
> index e263d62ae2d0..feb691eb4c64 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -563,6 +563,7 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
> unsigned long nstart, end, tmp;
> struct vm_area_struct *vma, *prev;
> int error;
> + MA_STATE(mas, &current->mm->mm_mt, start, start);
>
> VM_BUG_ON(offset_in_page(start));
> VM_BUG_ON(len != PAGE_ALIGN(len));
> @@ -571,11 +572,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
> return -EINVAL;
> if (end == start)
> return 0;
> - vma = find_vma(current->mm, start);
> - if (!vma || vma->vm_start > start)
> + vma = mas_walk(&mas);
> + if (!vma)
> return -ENOMEM;
>
> - prev = vma->vm_prev;
> + prev = mas_prev(&mas, 0);

Could be only done as an 'else' of the 'if' below?

> if (start > vma->vm_start)
> prev = vma;
>
> @@ -597,7 +598,7 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
> if (nstart >= end)
> break;
>
> - vma = prev->vm_next;
> + vma = find_vma(prev->vm_mm, prev->vm_end);
> if (!vma || vma->vm_start != nstart) {
> error = -ENOMEM;
> break;
> @@ -618,15 +619,12 @@ static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
> {
> struct vm_area_struct *vma;
> unsigned long count = 0;
> + MA_STATE(mas, &mm->mm_mt, start, start);
>
> if (mm == NULL)
> mm = current->mm;
>
> - vma = find_vma(mm, start);
> - if (vma == NULL)
> - return 0;
> -
> - for (; vma ; vma = vma->vm_next) {
> + mas_for_each(&mas, vma, start + len) {

Could be for_each_vma_range()?

> if (start >= vma->vm_end)
> continue;

Unnecessary? (even before this patch, I think?)

> if (start + len <= vma->vm_start)

Unnecessary after your patch?

> @@ -741,6 +739,7 @@ static int apply_mlockall_flags(int flags)
> {
> struct vm_area_struct *vma, *prev = NULL;
> vm_flags_t to_add = 0;
> + unsigned long addr = 0;
>
> current->mm->def_flags &= VM_LOCKED_CLEAR_MASK;
> if (flags & MCL_FUTURE) {
> @@ -759,7 +758,7 @@ static int apply_mlockall_flags(int flags)
> to_add |= VM_LOCKONFAULT;
> }
>
> - for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
> + mt_for_each(&current->mm->mm_mt, vma, addr, ULONG_MAX) {
> vm_flags_t newflags;
>
> newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;

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