lkml.org 
[lkml]   [2022]   [Jun]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v10 10/69] mmap: use the VMA iterator in count_vma_pages_range()
Date
* David Hildenbrand <david@redhat.com> [220621 17:13]:
> On 21.06.22 22:46, Liam Howlett wrote:
> > From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> >
> > This simplifies the implementation and is faster than using the linked
> > list.
> >
> > Link: https://lkml.kernel.org/r/20220504010716.661115-12-Liam.Howlett@oracle.com
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
> > Acked-by: Vlastimil Babka <vbabka@suse.cz>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: David Howells <dhowells@redhat.com>
> > Cc: SeongJae Park <sj@kernel.org>
> > Cc: Will Deacon <will@kernel.org>
> > Cc: Davidlohr Bueso <dave@stgolabs.net>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > mm/mmap.c | 24 +++++++-----------------
> > 1 file changed, 7 insertions(+), 17 deletions(-)
> >
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index 6be7833c781b..d7e6baa2f40f 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -675,29 +675,19 @@ 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);
>
> I thought using max_t and min_t was the latest advisory. I might be
> wrong and simply kept doing it that way ;)

They are the same type so I think this is okay.

>
> >
> > - overlap_len = min(end, vma->vm_end) - vma->vm_start;
> > - nr_pages += overlap_len >> PAGE_SHIFT;
> > + nr_pages += (vm_end - vm_start) / PAGE_SIZE;
>
> PHYS_PFN(vm_end - vm_start)
>
> > }
> >
> > return nr_pages;
>
> Reviewed-by: David Hildenbrand <david@redhat.com>
>
> --
> Thanks,
>
> David / dhildenb
>
\
 
 \ /
  Last update: 2022-06-24 15:11    [W:0.087 / U:0.880 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site