On Tue, Oct 27, 2020 at 08:04:08PM +0100, Lorenzo Bianconi wrote:
> Introduce the capability to batch page_pool ptr_ring refill since it is
> usually run inside the driver NAPI tx completion loop.
>
> Suggested-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
> include/net/page_pool.h | 26 ++++++++++++++++++++++++++
> net/core/page_pool.c | 33 +++++++++++++++++++++++++++++++++
> net/core/xdp.c | 9 ++-------
> 3 files changed, 61 insertions(+), 7 deletions(-)
>
> diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> index 81d7773f96cd..b5b195305346 100644
> --- a/include/net/page_pool.h
> +++ b/include/net/page_pool.h
> @@ -152,6 +152,8 @@ struct page_pool *page_pool_create(const struct page_pool_params *params);
> void page_pool_destroy(struct page_pool *pool);
> void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *));
> void page_pool_release_page(struct page_pool *pool, struct page *page);
> +void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> + int count);
> #else
> static inline void page_pool_destroy(struct page_pool *pool)
> {
> @@ -165,6 +167,11 @@ static inline void page_pool_release_page(struct page_pool *pool,
> struct page *page)
> {
> }
> +
> +static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> + int count)
> +{
> +}
> #endif
>
> void page_pool_put_page(struct page_pool *pool, struct page *page,
> @@ -215,4 +222,23 @@ static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid)
> if (unlikely(pool->p.nid != new_nid))
> page_pool_update_nid(pool, new_nid);
> }
> +
> +static inline void page_pool_ring_lock(struct page_pool *pool)
> + __acquires(&pool->ring.producer_lock)
> +{
> + if (in_serving_softirq())
> + spin_lock(&pool->ring.producer_lock);
> + else
> + spin_lock_bh(&pool->ring.producer_lock);
> +}
> +
> +static inline void page_pool_ring_unlock(struct page_pool *pool)
> + __releases(&pool->ring.producer_lock)
> +{
> + if (in_serving_softirq())
> + spin_unlock(&pool->ring.producer_lock);
> + else
> + spin_unlock_bh(&pool->ring.producer_lock);
> +}
> +
> #endif /* _NET_PAGE_POOL_H */
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index ef98372facf6..84fb21f8865e 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -11,6 +11,8 @@
> #include <linux/device.h>
>
> #include <net/page_pool.h>
> +#include <net/xdp.h>
> +
> #include <linux/dma-direction.h>
> #include <linux/dma-mapping.h>
> #include <linux/page-flags.h>
> @@ -408,6 +410,37 @@ void page_pool_put_page(struct page_pool *pool, struct page *page,
> }
> EXPORT_SYMBOL(page_pool_put_page);
>
> +void page_pool_put_page_bulk(struct page_pool *pool, void **data,
> + int count)
> +{
> + struct page *page_ring[XDP_BULK_QUEUE_SIZE];
> + int i, len = 0;
> +
> + for (i = 0; i < count; i++) {
> + struct page *page = virt_to_head_page(data[i]);
> +
> + if (unlikely(page_ref_count(page) != 1 ||
> + !pool_page_reusable(pool, page))) {
> + page_pool_release_page(pool, page);
> + put_page(page);
> + continue;
> + }
> +
> + if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
> + page_pool_dma_sync_for_device(pool, page, -1);
> +
> + page_ring[len++] = page;
> + }
> +
> + page_pool_ring_lock(pool);
> + for (i = 0; i < len; i++) {
> + if (__ptr_ring_produce(&pool->ring, page_ring[i]))
> + page_pool_return_page(pool, page_ring[i]);
Can we add a comment here on why the explicit spinlock needs to protect
page_pool_return_page() as well instead of just using ptr_ring_produce()?
> + }
> + page_pool_ring_unlock(pool);
> +}
> +EXPORT_SYMBOL(page_pool_put_page_bulk);
> +
> static void page_pool_empty_ring(struct page_pool *pool)
> {
> struct page *page;
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 93eabd789246..9f9a8d14df38 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -383,16 +383,11 @@ EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
> void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
> {
> struct xdp_mem_allocator *xa = bq->xa;
> - int i;
>
> - if (unlikely(!xa))
> + if (unlikely(!xa || !bq->count))
> return;
>
> - for (i = 0; i < bq->count; i++) {
> - struct page *page = virt_to_head_page(bq->q[i]);
> -
> - page_pool_put_full_page(xa->page_pool, page, false);
> - }
> + page_pool_put_page_bulk(xa->page_pool, bq->q, bq->count);
> bq->count = 0;
> }
> EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk);
> --
> 2.26.2
>
Thanks
/Ilias
