On 28 Jan 2021, at 2:03, Matthew Wilcox (Oracle) wrote:
> If we know we have a folio, we can call put_folio() instead of put_page()
> and save the overhead of calling compound_head(). Also skips the
> devmap checks.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> include/linux/mm.h | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 7d787229dd40..873d649107ba 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1220,9 +1220,15 @@ static inline __must_check bool try_get_page(struct page *page)
> return true;
> }
>
> +static inline void put_folio(struct folio *folio)
> +{
> + if (put_page_testzero(&folio->page))
> + __put_page(&folio->page);
> +}
> +
> static inline void put_page(struct page *page)
> {
> - page = compound_head(page);
> + struct folio *folio = page_folio(page);
>
> /*
> * For devmap managed pages we need to catch refcount transition from
> @@ -1230,13 +1236,12 @@ static inline void put_page(struct page *page)
> * need to inform the device driver through callback. See
> * include/linux/memremap.h and HMM for details.
> */
> - if (page_is_devmap_managed(page)) {
> - put_devmap_managed_page(page);
> + if (page_is_devmap_managed(&folio->page)) {
> + put_devmap_managed_page(&folio->page);
> return;
> }
>
> - if (put_page_testzero(page))
> - __put_page(page);
> + put_folio(folio);
> }
>
> /*
> --
> 2.29.2
LGTM.
Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
—
Best Regards,
Yan Zi
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