* Vlastimil Babka <vbabka@xxxxxxx> [211209 10:54]:
> 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.
Thanks for catching this. I will clean up the s-o-b for the next
revision.
>
> > ---
> > 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;
>
