On Wed, 19 Dec 2018 12:06:51 -0800
Jonathan Lemon <jonathan.le...@gmail.com> wrote:
> Return pfmemalloc pages back to the page allocator, instead of
> holding them in the page pool.
Have you experience this issue in practice or is it theory?
> While here, also use the __page_pool_return_page() API.
Don't combine several unrelated changed in one patch.
> Signed-off-by: Jonathan Lemon <jonathan.le...@gmail.com>
> ---
> net/core/page_pool.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 43a932cb609b..091007ff14a3 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -233,7 +233,7 @@ void __page_pool_put_page(struct page_pool *pool,
> *
> * refcnt == 1 means page_pool owns page, and can recycle it.
> */
> - if (likely(page_ref_count(page) == 1)) {
> + if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) {
I don't like adding this in the hot-path. Instead we could move this
to the page alloc slow-path, and reject allocating pages with
pgmemalloc in the first place.
> /* Read barrier done in page_ref_count / READ_ONCE */
>
> if (allow_direct && in_serving_softirq())
> @@ -259,8 +259,7 @@ void __page_pool_put_page(struct page_pool *pool,
> * doing refcnt based recycle tricks, meaning another process
> * will be invoking put_page.
> */
> - __page_pool_clean_page(pool, page);
> - put_page(page);
> + __page_pool_return_page(pool, page);
> }
> EXPORT_SYMBOL(__page_pool_put_page);
>
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
