On 12/1/21 15:29, Liam Howlett wrote:
> From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
>
> This simplifies the implementation and is faster than using the linked
> list.
You mean faster because more cache friendly?
OTOH you do max(addr, vma->vm_start) which wasn't the case.
I doubt it matters though and yeah it's much simpler...
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Btw, no signed-off-by Liam?
I now also notice some other patches (e.g. patch 4) have From: and s-o-b by
Liam followed by Matthew, despite it's Liam sending them. I guess that's
less of an issue than the missing one.
Anyway something for you to check and make consistent in the whole series, I
won't point it out individually.
> ---
> mm/mmap.c | 24 +++++++-----------------
> 1 file changed, 7 insertions(+), 17 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 9fee6e6b276f..de78fc0ce809 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -669,29 +669,19 @@ munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
>
> return 0;
> }
> +
> static unsigned long count_vma_pages_range(struct mm_struct *mm,
> unsigned long addr, unsigned long end)
> {
> - unsigned long nr_pages = 0;
> + VMA_ITERATOR(vmi, mm, addr);
> struct vm_area_struct *vma;
> + unsigned long nr_pages = 0;
>
> - /* Find first overlapping mapping */
> - vma = find_vma_intersection(mm, addr, end);
> - if (!vma)
> - return 0;
> -
> - nr_pages = (min(end, vma->vm_end) -
> - max(addr, vma->vm_start)) >> PAGE_SHIFT;
> -
> - /* Iterate over the rest of the overlaps */
> - for (vma = vma->vm_next; vma; vma = vma->vm_next) {
> - unsigned long overlap_len;
> -
> - if (vma->vm_start > end)
> - break;
> + for_each_vma_range(vmi, vma, end) {
> + unsigned long vm_start = max(addr, vma->vm_start);
> + unsigned long vm_end = min(end, vma->vm_end);
>
> - overlap_len = min(end, vma->vm_end) - vma->vm_start;
> - nr_pages += overlap_len >> PAGE_SHIFT;
> + nr_pages += (vm_end - vm_start) / PAGE_SIZE;
> }
>
> return nr_pages;
