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[85.73.10.175]) by smtp.gmail.com with ESMTPSA id q6sm3336559wma.0.2020.10.29.21.32.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Oct 2020 21:32:56 -0700 (PDT) Date: Fri, 30 Oct 2020 06:32:54 +0200 From: Ilias Apalodimas To: Lorenzo Bianconi Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, lorenzo.bianconi@redhat.com, davem@davemloft.net, kuba@kernel.org, brouer@redhat.com Subject: Re: [PATCH v2 net-next 1/4] net: xdp: introduce bulking for xdp tx return path Message-ID: <20201030043254.GA100756@apalos.home> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Lorenzo, On Thu, Oct 29, 2020 at 08:28:44PM +0100, Lorenzo Bianconi wrote: > 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. > Convert mvneta driver to xdp_return_frame_bulk APIs. > > Suggested-by: Jesper Dangaard Brouer > Signed-off-by: Lorenzo Bianconi > --- > drivers/net/ethernet/marvell/mvneta.c | 5 ++- > include/net/xdp.h | 9 ++++ > net/core/xdp.c | 61 +++++++++++++++++++++++++++ > 3 files changed, 74 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c > index 54b0bf574c05..43ab8a73900e 100644 > --- a/drivers/net/ethernet/marvell/mvneta.c > +++ b/drivers/net/ethernet/marvell/mvneta.c > @@ -1834,8 +1834,10 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp, > struct netdev_queue *nq, bool napi) > { > unsigned int bytes_compl = 0, pkts_compl = 0; > + struct xdp_frame_bulk bq; > int i; > > + bq.xa = NULL; > for (i = 0; i < num; i++) { > struct mvneta_tx_buf *buf = &txq->buf[txq->txq_get_index]; > struct mvneta_tx_desc *tx_desc = txq->descs + > @@ -1857,9 +1859,10 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp, > if (napi && buf->type == MVNETA_TYPE_XDP_TX) > xdp_return_frame_rx_napi(buf->xdpf); > else > - xdp_return_frame(buf->xdpf); > + xdp_return_frame_bulk(buf->xdpf, &bq); > } > } > + xdp_flush_frame_bulk(&bq); > > netdev_tx_completed_queue(nq, pkts_compl, bytes_compl); > } Sorry I completely forgot to mention this on the v1 review. I think this belongs to a patch of it's own similar to mellanox and mvpp2 drivers > diff --git a/include/net/xdp.h b/include/net/xdp.h > index 3814fb631d52..a1f48a73e6df 100644 > --- a/include/net/xdp.h > +++ b/include/net/xdp.h > @@ -104,6 +104,12 @@ struct xdp_frame { > struct net_device *dev_rx; /* used by cpumap */ > }; > > +#define XDP_BULK_QUEUE_SIZE 16 > +struct xdp_frame_bulk { > + int count; > + void *xa; > + void *q[XDP_BULK_QUEUE_SIZE]; > +}; > > static inline struct skb_shared_info * > xdp_get_shared_info_from_frame(struct xdp_frame *frame) > @@ -194,6 +200,9 @@ struct xdp_frame *xdp_convert_buff_to_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); > +void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq); > +void xdp_return_frame_bulk(struct xdp_frame *xdpf, > + struct xdp_frame_bulk *bq); > > /* When sending xdp_frame into the network stack, then there is no > * return point callback, which is needed to release e.g. DMA-mapping > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 48aba933a5a8..66ac275a0360 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -380,6 +380,67 @@ 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->count = 0; > +} > +EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk); > + > +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; > + } > + > + rcu_read_lock(); > + > + 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 (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; > + > + rcu_read_unlock(); > +} > +EXPORT_SYMBOL_GPL(xdp_return_frame_bulk); > + > void xdp_return_buff(struct xdp_buff *xdp) > { > __xdp_return(xdp->data, &xdp->rxq->mem, true); > -- > 2.26.2 > Cheers /Ilias