Hi, Le dimanche 10 mai 2015 à 00:51 -0700, Yuval Shaia a écrit : > By default, IPoIB-CM driver uses 64k MTU. Larger MTU gives better performance. > This MTU plus overhead puts the memory allocation for IP based packets at 32 > 4k pages (order 5), which have to be contiguous. > When the system memory under pressure, it was observed that allocating 128k > contiguous physical memory is difficult and causes serious errors (such as > system becomes unusable). Please add an empty line to start a new paragraph. > This enhancement resolve the issue by removing the physically contiguous memory > requirement using Scatter/Gather feature that exists in Linux stack. > > With this fix Scatter-Gather will be supported also in connected mode. > > This change reverts the some of the change made in commit e112373 use 12 hex-digits identifier: git config [--global] core.abbrev 12 See https://lkml.org/lkml/2010/10/28/287 > ("IPoIB/cm: Reduce connected mode TX object size)". > > The ability to use SG in IPoIB CM is possible because the coupling > between NETIF_F_SG and NETIF_F_CSUM was removed in commit ec5f061 likewise. > ("net: Kill link between CSUM and SG features.") > Commit message is way better than the initial one[1], thanks a lot for all the explanation. [1] http://marc.info/?i=1422357682-8934-1-git-send-email-yuval.shaia@xxxxxxxxxx http://mid.gmane.org/1422357682-8934-1-git-send-email-yuval.shaia@xxxxxxxxxx > Signed-off-by: Yuval Shaia <yuval.shaia@xxxxxxxxxx> > --- > v2: Enhance commit log message > > I'd like to thank John Sobecki <john.sobecki@xxxxxxxxxx> and > Christian Marie <christian@xxxxxxxxx> for helping me with reviewing this patch. > I will be glad if you can ACK it. > --- > drivers/infiniband/ulp/ipoib/ipoib.h | 4 +- > drivers/infiniband/ulp/ipoib/ipoib_cm.c | 107 +++++++++++++++++++++++------ > drivers/infiniband/ulp/ipoib/ipoib_ib.c | 3 +- > drivers/infiniband/ulp/ipoib/ipoib_main.c | 2 +- > 4 files changed, 92 insertions(+), 24 deletions(-) > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib.h b/drivers/infiniband/ulp/ipoib/ipoib.h > index bd94b0a..372c8a2 100644 > --- a/drivers/infiniband/ulp/ipoib/ipoib.h > +++ b/drivers/infiniband/ulp/ipoib/ipoib.h > @@ -239,7 +239,7 @@ struct ipoib_cm_tx { > struct net_device *dev; > struct ipoib_neigh *neigh; > struct ipoib_path *path; > - struct ipoib_cm_tx_buf *tx_ring; > + struct ipoib_tx_buf *tx_ring; > unsigned tx_head; > unsigned tx_tail; > unsigned long flags; > @@ -504,6 +504,8 @@ int ipoib_mcast_stop_thread(struct net_device *dev); > void ipoib_mcast_dev_down(struct net_device *dev); > void ipoib_mcast_dev_flush(struct net_device *dev); > > +int ipoib_dma_map_tx(struct ib_device *ca, struct ipoib_tx_buf *tx_req); > + > #ifdef CONFIG_INFINIBAND_IPOIB_DEBUG > struct ipoib_mcast_iter *ipoib_mcast_iter_init(struct net_device *dev); > int ipoib_mcast_iter_next(struct ipoib_mcast_iter *iter); > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > index 56959ad..eae106e 100644 > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c > @@ -88,6 +88,31 @@ static void ipoib_cm_dma_unmap_rx(struct ipoib_dev_priv *priv, int frags, > ib_dma_unmap_page(priv->ca, mapping[i + 1], PAGE_SIZE, DMA_FROM_DEVICE); > } > > +static void ipoib_cm_dma_unmap_tx(struct ipoib_dev_priv *priv, > + struct ipoib_tx_buf *tx_req) > +{ > + struct sk_buff *skb; > + int i, offs; > + > + skb = tx_req->skb; > + if (skb_shinfo(skb)->nr_frags) { > + offs = 0; > + if (skb_headlen(skb)) { > + ib_dma_unmap_single(priv->ca, tx_req->mapping[0], > + skb_headlen(skb), DMA_TO_DEVICE); > + offs = 1; I would have use a pointer instead of an index: mapping = &tx_req->mapping[1]; > + } else mapping = &tx_req->mapping[0]; > + for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) { , mapping ++ > + const skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; > + > + ib_dma_unmap_page(priv->ca, tx_req->mapping[i + offs], mapping > + skb_frag_size(frag), DMA_TO_DEVICE); > + } > + } else > + ib_dma_unmap_single(priv->ca, tx_req->mapping[0], skb->len, > + DMA_TO_DEVICE); See below, I think scatter/gather can be the default to keep a single code path. > +} > + > static int ipoib_cm_post_receive_srq(struct net_device *dev, int id) > { > struct ipoib_dev_priv *priv = netdev_priv(dev); > @@ -707,11 +732,39 @@ static inline int post_send(struct ipoib_dev_priv *priv, > return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr); > } > > +static inline int post_send_sg(struct ipoib_dev_priv *priv, > + struct ipoib_cm_tx *tx, > + unsigned int wr_id, > + struct sk_buff *skb, > + u64 mapping[MAX_SKB_FRAGS + 1]) > +{ > + struct ib_send_wr *bad_wr; > + int i, off; > + skb_frag_t *frags = skb_shinfo(skb)->frags; > + int nr_frags = skb_shinfo(skb)->nr_frags; > + > + if (skb_headlen(skb)) { > + priv->tx_sge[0].addr = mapping[0]; > + priv->tx_sge[0].length = skb_headlen(skb); > + off = 1; Same here, I would prefer a pointer instead of using offset. sge = &tx_sge[1]; mapping++; > + } else > + off = 0; sge = &tx_sge[0]; > + > + for (i = 0; i < nr_frags; ++i) { > + priv->tx_sge[i + off].addr = mapping[i + off]; > + priv->tx_sge[i + off].length = frags[i].size; sge->addr = *mapping; sge->length = *frags; mapping ++; frags ++; sge ++; > + } > + priv->tx_wr.num_sge = nr_frags + off; > + priv->tx_wr.wr_id = wr_id | IPOIB_OP_CM; > + > + return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr); > +} > + > void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_tx *tx) > { > struct ipoib_dev_priv *priv = netdev_priv(dev); > - struct ipoib_cm_tx_buf *tx_req; > - u64 addr; > + struct ipoib_tx_buf *tx_req; > + u64 addr = 0; > int rc; > > if (unlikely(skb->len > tx->mtu)) { > @@ -735,24 +788,37 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_ > */ > tx_req = &tx->tx_ring[tx->tx_head & (ipoib_sendq_size - 1)]; > tx_req->skb = skb; > - addr = ib_dma_map_single(priv->ca, skb->data, skb->len, DMA_TO_DEVICE); > - if (unlikely(ib_dma_mapping_error(priv->ca, addr))) { > - ++dev->stats.tx_errors; > - dev_kfree_skb_any(skb); > - return; > - } > > - tx_req->mapping = addr; > + if (skb_shinfo(skb)->nr_frags) { > + if (unlikely(ipoib_dma_map_tx(priv->ca, tx_req))) { > + ++dev->stats.tx_errors; > + dev_kfree_skb_any(skb); > + return; > + } > + rc = post_send_sg(priv, tx, tx->tx_head & > + (ipoib_sendq_size - 1), > + skb, tx_req->mapping); > + } else { > + addr = ib_dma_map_single(priv->ca, skb->data, skb->len, > + DMA_TO_DEVICE); Is there any advantage to keep a separate path to handle single fragment ? If not, I believe it would be better (simpler) to use post_send_sg() in all case as it would remove code here and in ipoib_cm_dma_unmap_tx(). > + if (unlikely(ib_dma_mapping_error(priv->ca, addr))) { > + ++dev->stats.tx_errors; > + dev_kfree_skb_any(skb); > + return; > + } > + > + tx_req->mapping[0] = addr; > > - skb_orphan(skb); > - skb_dst_drop(skb); > + skb_orphan(skb); > + skb_dst_drop(skb); > > - rc = post_send(priv, tx, tx->tx_head & (ipoib_sendq_size - 1), > - addr, skb->len); > + rc = post_send(priv, tx, tx->tx_head & (ipoib_sendq_size - 1), > + addr, skb->len); > + } > if (unlikely(rc)) { > ipoib_warn(priv, "post_send failed, error %d\n", rc); > ++dev->stats.tx_errors; > - ib_dma_unmap_single(priv->ca, addr, skb->len, DMA_TO_DEVICE); > + ipoib_cm_dma_unmap_tx(priv, tx_req); > dev_kfree_skb_any(skb); > } else { > dev->trans_start = jiffies; > @@ -777,7 +843,7 @@ void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc) > struct ipoib_dev_priv *priv = netdev_priv(dev); > struct ipoib_cm_tx *tx = wc->qp->qp_context; > unsigned int wr_id = wc->wr_id & ~IPOIB_OP_CM; > - struct ipoib_cm_tx_buf *tx_req; > + struct ipoib_tx_buf *tx_req; > unsigned long flags; > > ipoib_dbg_data(priv, "cm send completion: id %d, status: %d\n", > @@ -791,7 +857,7 @@ void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc) > > tx_req = &tx->tx_ring[wr_id]; > > - ib_dma_unmap_single(priv->ca, tx_req->mapping, tx_req->skb->len, DMA_TO_DEVICE); > + ipoib_cm_dma_unmap_tx(priv, tx_req); > > /* FIXME: is this right? Shouldn't we only increment on success? */ > ++dev->stats.tx_packets; > @@ -1036,6 +1102,9 @@ static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ipoib_ > > struct ib_qp *tx_qp; > > + if (dev->features & NETIF_F_SG) > + attr.cap.max_send_sge = MAX_SKB_FRAGS + 1; > + > tx_qp = ib_create_qp(priv->pd, &attr); > if (PTR_ERR(tx_qp) == -EINVAL) { > ipoib_warn(priv, "can't use GFP_NOIO for QPs on device %s, using GFP_KERNEL\n", > @@ -1170,7 +1239,7 @@ err_tx: > static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p) > { > struct ipoib_dev_priv *priv = netdev_priv(p->dev); > - struct ipoib_cm_tx_buf *tx_req; > + struct ipoib_tx_buf *tx_req; > unsigned long begin; > > ipoib_dbg(priv, "Destroy active connection 0x%x head 0x%x tail 0x%x\n", > @@ -1197,8 +1266,7 @@ timeout: > > while ((int) p->tx_tail - (int) p->tx_head < 0) { > tx_req = &p->tx_ring[p->tx_tail & (ipoib_sendq_size - 1)]; > - ib_dma_unmap_single(priv->ca, tx_req->mapping, tx_req->skb->len, > - DMA_TO_DEVICE); > + ipoib_cm_dma_unmap_tx(priv, tx_req); > dev_kfree_skb_any(tx_req->skb); > ++p->tx_tail; > netif_tx_lock_bh(p->dev); > @@ -1455,7 +1523,6 @@ static void ipoib_cm_stale_task(struct work_struct *work) > spin_unlock_irq(&priv->lock); > } > > - useless white space change ! > static ssize_t show_mode(struct device *d, struct device_attribute *attr, > char *buf) > { > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c > index 63b92cb..f886055 100644 > --- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c > +++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c > @@ -263,8 +263,7 @@ repost: > "for buf %d\n", wr_id); > } > > -static int ipoib_dma_map_tx(struct ib_device *ca, > - struct ipoib_tx_buf *tx_req) > +int ipoib_dma_map_tx(struct ib_device *ca, struct ipoib_tx_buf *tx_req) > { > struct sk_buff *skb = tx_req->skb; > u64 *mapping = tx_req->mapping; > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c > index 9e1b203..4ee2784 100644 > --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c > +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c > @@ -190,7 +190,7 @@ static netdev_features_t ipoib_fix_features(struct net_device *dev, netdev_featu > struct ipoib_dev_priv *priv = netdev_priv(dev); > > if (test_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags)) > - features &= ~(NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO); > + features &= ~(NETIF_F_IP_CSUM | NETIF_F_TSO); > > return features; > } Regards. -- Yann Droneaud OPTEYA -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
