From 8965398713d831f6b893805880c249e62e9059ae Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Fri, 13 Nov 2020 12:48:28 +0100 Subject: net: xdp: Introduce bulking for xdp tx return path XDP bulk APIs introduce a defer/flush mechanism to return pages belonging to the same xdp_mem_allocator object (identified via the mem.id field) in bulk to optimize I-cache and D-cache since xdp_return_frame is usually run inside the driver NAPI tx completion loop. The bulk queue size is set to 16 to be aligned to how XDP_REDIRECT bulking works. The bulk is flushed when it is full or when mem.id changes. xdp_frame_bulk is usually stored/allocated on the function call-stack to avoid locking penalties. Current implementation considers only page_pool memory model. Suggested-by: Jesper Dangaard Brouer Co-developed-by: Jesper Dangaard Brouer Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Lorenzo Bianconi Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Ilias Apalodimas Link: https://lore.kernel.org/bpf/e190c03eac71b20c8407ae0fc2c399eda7835f49.1605267335.git.lorenzo@kernel.org --- net/core/xdp.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'net/core/xdp.c') diff --git a/net/core/xdp.c b/net/core/xdp.c index 48aba933a5a8..bbaee7fdd44f 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -380,6 +380,65 @@ void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) } EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); +/* XDP bulk APIs introduce a defer/flush mechanism to return + * pages belonging to the same xdp_mem_allocator object + * (identified via the mem.id field) in bulk to optimize + * I-cache and D-cache. + * The bulk queue size is set to 16 to be aligned to how + * XDP_REDIRECT bulking works. The bulk is flushed when + * it is full or when mem.id changes. + * xdp_frame_bulk is usually stored/allocated on the function + * call-stack to avoid locking penalties. + */ +void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq) +{ + struct xdp_mem_allocator *xa = bq->xa; + int i; + + if (unlikely(!xa)) + 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); + } + /* bq->xa is not cleared to save lookup, if mem.id same in next bulk */ + bq->count = 0; +} +EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk); + +/* Must be called with rcu_read_lock held */ +void xdp_return_frame_bulk(struct xdp_frame *xdpf, + struct xdp_frame_bulk *bq) +{ + struct xdp_mem_info *mem = &xdpf->mem; + struct xdp_mem_allocator *xa; + + if (mem->type != MEM_TYPE_PAGE_POOL) { + __xdp_return(xdpf->data, &xdpf->mem, false); + return; + } + + xa = bq->xa; + if (unlikely(!xa)) { + xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); + bq->count = 0; + bq->xa = xa; + } + + if (bq->count == XDP_BULK_QUEUE_SIZE) + xdp_flush_frame_bulk(bq); + + if (unlikely(mem->id != xa->mem.id)) { + xdp_flush_frame_bulk(bq); + bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); + } + + bq->q[bq->count++] = xdpf->data; +} +EXPORT_SYMBOL_GPL(xdp_return_frame_bulk); + void xdp_return_buff(struct xdp_buff *xdp) { __xdp_return(xdp->data, &xdp->rxq->mem, true); -- cgit v1.2.3