Re: [PATCH net-next v2 08/18] page_pool: make page_pool_put_page_bulk() actually handle array of pages

Maciej Fijalkowski
2024-10-17T11:33:50Z

On Tue, Oct 15, 2024 at 04:53:40PM +0200, Alexander Lobakin wrote:
> Currently, page_pool_put_page_bulk() indeed takes an array of pointers
> to the data, not pages, despite the name. As one side effect, when
> you're freeing frags from &skb_shared_info, xdp_return_frame_bulk()
> converts page pointers to virtual addresses and then
> page_pool_put_page_bulk() converts them back.
> Make page_pool_put_page_bulk() actually handle array of pages. Pass
> frags directly and use virt_to_page() when freeing xdpf->data, so that
> the PP core will then get the compound head and take care of the rest.

OTOH this one makes sense to me as a part of this patchset, plus i like
that you are getting rid of virt to page dances.

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

Any small improvements observed when doing micro benchmarks on your side?

>
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
> ---
> include/net/page_pool/types.h | 8 ++++----
> include/net/xdp.h | 2 +-
> net/core/page_pool.c | 6 +++---
> net/core/xdp.c | 4 ++--
> 4 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
> index c022c410abe3..6c1be99a5959 100644
> --- a/include/net/page_pool/types.h
> +++ b/include/net/page_pool/types.h
> @@ -259,8 +259,8 @@ void page_pool_disable_direct_recycling(struct page_pool *pool);
> void page_pool_destroy(struct page_pool *pool);
> void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
> const struct xdp_mem_info *mem);
> -void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> - int count);
> +void page_pool_put_page_bulk(struct page_pool *pool, struct page **data,
> + u32 count);
> #else
> static inline void page_pool_destroy(struct page_pool *pool)
> {
> @@ -272,8 +272,8 @@ static inline void page_pool_use_xdp_mem(struct page_pool *pool,
> {
> }
>
> -static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> - int count)
> +static inline void page_pool_put_page_bulk(struct page_pool *pool,
> + struct page **data, u32 count)
> {
> }
> #endif
> diff --git a/include/net/xdp.h b/include/net/xdp.h
> index 3e748bb916d3..4416cd4b5086 100644
> --- a/include/net/xdp.h
> +++ b/include/net/xdp.h
> @@ -194,7 +194,7 @@ xdp_frame_is_frag_pfmemalloc(const struct xdp_frame *frame)
> struct xdp_frame_bulk {
> int count;
> void *xa;
> - void *q[XDP_BULK_QUEUE_SIZE];
> + struct page *q[XDP_BULK_QUEUE_SIZE];
> };
>
> static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index a813d30d2135..ad219206ee8d 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -854,8 +854,8 @@ EXPORT_SYMBOL(page_pool_put_unrefed_page);
> * Please note the caller must not use data area after running
> * page_pool_put_page_bulk(), as this function overwrites it.
> */
> -void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> - int count)
> +void page_pool_put_page_bulk(struct page_pool *pool, struct page **data,
> + u32 count)
> {
> int i, bulk_len = 0;
> bool allow_direct;
> @@ -864,7 +864,7 @@ void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> allow_direct = page_pool_napi_local(pool);
>
> for (i = 0; i < count; i++) {
> - netmem_ref netmem = page_to_netmem(virt_to_head_page(data[i]));
> + netmem_ref netmem = page_to_netmem(compound_head(data[i]));
>
> /* It is not the last user for the page frag case */
> if (!page_pool_is_last_ref(netmem))
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index bd2aa340baad..779e646f347b 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -556,12 +556,12 @@ void xdp_return_frame_bulk(struct xdp_frame *xdpf,
> for (i = 0; i < sinfo->nr_frags; i++) {
> skb_frag_t *frag = &sinfo->frags[i];
>
> - bq->q[bq->count++] = skb_frag_address(frag);
> + bq->q[bq->count++] = skb_frag_page(frag);
> if (bq->count == XDP_BULK_QUEUE_SIZE)
> xdp_flush_frame_bulk(bq);
> }
> }
> - bq->q[bq->count++] = xdpf->data;
> + bq->q[bq->count++] = virt_to_page(xdpf->data);
> }
> EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
>
> --
> 2.46.2
>