lkml.org 
[lkml]   [2021]   [Dec]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v1 03/11] mm: simplify hugetlb and file-THP handling in __page_mapcount()
On Fri, Dec 17, 2021 at 3:33 AM David Hildenbrand <david@redhat.com> wrote:
>
> Let's return early for hugetlb, which really only relies on the compound
> mapcount so far and does not support PageDoubleMap() yet. Use the chance
> to cleanup the file-THP case to make it easier to grasp. While at it, use
> head_compound_mapcount().
>
> This is a preparation for further changes.
>
> Reviewed-by: Peter Xu <peterx@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Yang Shi <shy828301@gmail.com>

> ---
> mm/util.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/mm/util.c b/mm/util.c
> index 741ba32a43ac..3239e75c148d 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -732,15 +732,18 @@ int __page_mapcount(struct page *page)
> {
> int ret;
>
> - ret = atomic_read(&page->_mapcount) + 1;
> + if (PageHuge(page))
> + return compound_mapcount(page);
> /*
> * For file THP page->_mapcount contains total number of mapping
> * of the page: no need to look into compound_mapcount.
> */
> - if (!PageAnon(page) && !PageHuge(page))
> - return ret;
> + if (!PageAnon(page))
> + return atomic_read(&page->_mapcount) + 1;
> +
> + ret = atomic_read(&page->_mapcount) + 1;
> page = compound_head(page);
> - ret += atomic_read(compound_mapcount_ptr(page)) + 1;
> + ret += head_compound_mapcount(page);
> if (PageDoubleMap(page))
> ret--;
> return ret;
> --
> 2.31.1
>

\
 
 \ /
  Last update: 2021-12-17 20:09    [W:0.347 / U:0.476 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site