From 389ab7f01af988c2a1ec5617eb0c7e220df1ef1c Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Thu, 24 May 2018 16:46:07 +0200 Subject: xdp: introduce xdp_return_frame_rx_napi When sending an xdp_frame through xdp_do_redirect call, then error cases can happen where the xdp_frame needs to be dropped, and returning an -errno code isn't sufficient/possible any-longer (e.g. for cpumap case). This is already fully supported, by simply calling xdp_return_frame. This patch is an optimization, which provides xdp_return_frame_rx_napi, which is a faster variant for these error cases. It take advantage of the protection provided by XDP RX running under NAPI protection. This change is mostly relevant for drivers using the page_pool allocator as it can take advantage of this. (Tested with mlx5). Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov --- include/net/page_pool.h | 5 +++-- include/net/xdp.h | 1 + kernel/bpf/cpumap.c | 2 +- kernel/bpf/devmap.c | 2 +- net/core/xdp.c | 20 ++++++++++++++++---- 5 files changed, 22 insertions(+), 8 deletions(-) diff --git a/include/net/page_pool.h b/include/net/page_pool.h index c79087153148..694d055e01ef 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -115,13 +115,14 @@ void page_pool_destroy(struct page_pool *pool); void __page_pool_put_page(struct page_pool *pool, struct page *page, bool allow_direct); -static inline void page_pool_put_page(struct page_pool *pool, struct page *page) +static inline void page_pool_put_page(struct page_pool *pool, + struct page *page, bool allow_direct) { /* When page_pool isn't compiled-in, net/core/xdp.c doesn't * allow registering MEM_TYPE_PAGE_POOL, but shield linker. */ #ifdef CONFIG_PAGE_POOL - __page_pool_put_page(pool, page, false); + __page_pool_put_page(pool, page, allow_direct); #endif } /* Very limited use-cases allow recycle direct */ diff --git a/include/net/xdp.h b/include/net/xdp.h index 0b689cf561c7..7ad779237ae8 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -104,6 +104,7 @@ struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp) } void xdp_return_frame(struct xdp_frame *xdpf); +void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); void xdp_return_buff(struct xdp_buff *xdp); int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index c95b04ec103e..e0918d180f08 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -578,7 +578,7 @@ static int bq_flush_to_queue(struct bpf_cpu_map_entry *rcpu, err = __ptr_ring_produce(q, xdpf); if (err) { drops++; - xdp_return_frame(xdpf); + xdp_return_frame_rx_napi(xdpf); } processed++; } diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index ff2f3bf59f2f..a9cd5c93dd2b 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -239,7 +239,7 @@ static int bq_xmit_all(struct bpf_dtab_netdev *obj, err = dev->netdev_ops->ndo_xdp_xmit(dev, xdpf); if (err) { drops++; - xdp_return_frame(xdpf); + xdp_return_frame_rx_napi(xdpf); } else { sent++; } diff --git a/net/core/xdp.c b/net/core/xdp.c index bf6758f74339..cb8c4e061a5a 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -308,7 +308,13 @@ err: } EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); -static void xdp_return(void *data, struct xdp_mem_info *mem) +/* XDP RX runs under NAPI protection, and in different delivery error + * scenarios (e.g. queue full), it is possible to return the xdp_frame + * while still leveraging this protection. The @napi_direct boolian + * is used for those calls sites. Thus, allowing for faster recycling + * of xdp_frames/pages in those cases. + */ +static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct) { struct xdp_mem_allocator *xa; struct page *page; @@ -320,7 +326,7 @@ static void xdp_return(void *data, struct xdp_mem_info *mem) xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); page = virt_to_head_page(data); if (xa) - page_pool_put_page(xa->page_pool, page); + page_pool_put_page(xa->page_pool, page, napi_direct); else put_page(page); rcu_read_unlock(); @@ -340,12 +346,18 @@ static void xdp_return(void *data, struct xdp_mem_info *mem) void xdp_return_frame(struct xdp_frame *xdpf) { - xdp_return(xdpf->data, &xdpf->mem); + __xdp_return(xdpf->data, &xdpf->mem, false); } EXPORT_SYMBOL_GPL(xdp_return_frame); +void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) +{ + __xdp_return(xdpf->data, &xdpf->mem, true); +} +EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); + void xdp_return_buff(struct xdp_buff *xdp) { - xdp_return(xdp->data, &xdp->rxq->mem); + __xdp_return(xdp->data, &xdp->rxq->mem, true); } EXPORT_SYMBOL_GPL(xdp_return_buff); -- cgit v1.2.3-59-g8ed1b