IPoIB/cm: Improve small message bandwidth
Avoid the overhead of freeing/reallocating and mapping/unmapping for
DMA pages that have not been written to by hardware.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 4d59682..3484e8b 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -65,14 +65,14 @@
static int ipoib_cm_tx_handler(struct ib_cm_id *cm_id,
struct ib_cm_event *event);
-static void ipoib_cm_dma_unmap_rx(struct ipoib_dev_priv *priv,
+static void ipoib_cm_dma_unmap_rx(struct ipoib_dev_priv *priv, int frags,
u64 mapping[IPOIB_CM_RX_SG])
{
int i;
ib_dma_unmap_single(priv->ca, mapping[0], IPOIB_CM_HEAD_SIZE, DMA_FROM_DEVICE);
- for (i = 0; i < IPOIB_CM_RX_SG - 1; ++i)
+ for (i = 0; i < frags; ++i)
ib_dma_unmap_single(priv->ca, mapping[i + 1], PAGE_SIZE, DMA_FROM_DEVICE);
}
@@ -90,7 +90,8 @@
ret = ib_post_srq_recv(priv->cm.srq, &priv->cm.rx_wr, &bad_wr);
if (unlikely(ret)) {
ipoib_warn(priv, "post srq failed for buf %d (%d)\n", id, ret);
- ipoib_cm_dma_unmap_rx(priv, priv->cm.srq_ring[id].mapping);
+ ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
+ priv->cm.srq_ring[id].mapping);
dev_kfree_skb_any(priv->cm.srq_ring[id].skb);
priv->cm.srq_ring[id].skb = NULL;
}
@@ -98,8 +99,8 @@
return ret;
}
-static int ipoib_cm_alloc_rx_skb(struct net_device *dev, int id,
- u64 mapping[IPOIB_CM_RX_SG])
+static struct sk_buff *ipoib_cm_alloc_rx_skb(struct net_device *dev, int id, int frags,
+ u64 mapping[IPOIB_CM_RX_SG])
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct sk_buff *skb;
@@ -107,7 +108,7 @@
skb = dev_alloc_skb(IPOIB_CM_HEAD_SIZE + 12);
if (unlikely(!skb))
- return -ENOMEM;
+ return NULL;
/*
* IPoIB adds a 4 byte header. So we need 12 more bytes to align the
@@ -119,10 +120,10 @@
DMA_FROM_DEVICE);
if (unlikely(ib_dma_mapping_error(priv->ca, mapping[0]))) {
dev_kfree_skb_any(skb);
- return -EIO;
+ return NULL;
}
- for (i = 0; i < IPOIB_CM_RX_SG - 1; i++) {
+ for (i = 0; i < frags; i++) {
struct page *page = alloc_page(GFP_ATOMIC);
if (!page)
@@ -136,7 +137,7 @@
}
priv->cm.srq_ring[id].skb = skb;
- return 0;
+ return skb;
partial_error:
@@ -146,7 +147,7 @@
ib_dma_unmap_single(priv->ca, mapping[i + 1], PAGE_SIZE, DMA_FROM_DEVICE);
dev_kfree_skb_any(skb);
- return -ENOMEM;
+ return NULL;
}
static struct ib_qp *ipoib_cm_create_rx_qp(struct net_device *dev,
@@ -309,7 +310,7 @@
}
/* Adjust length of skb with fragments to match received data */
static void skb_put_frags(struct sk_buff *skb, unsigned int hdr_space,
- unsigned int length)
+ unsigned int length, struct sk_buff *toskb)
{
int i, num_frags;
unsigned int size;
@@ -326,7 +327,7 @@
if (length == 0) {
/* don't need this page */
- __free_page(frag->page);
+ skb_fill_page_desc(toskb, i, frag->page, 0, PAGE_SIZE);
--skb_shinfo(skb)->nr_frags;
} else {
size = min(length, (unsigned) PAGE_SIZE);
@@ -344,10 +345,11 @@
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
unsigned int wr_id = wc->wr_id & ~IPOIB_CM_OP_SRQ;
- struct sk_buff *skb;
+ struct sk_buff *skb, *newskb;
struct ipoib_cm_rx *p;
unsigned long flags;
u64 mapping[IPOIB_CM_RX_SG];
+ int frags;
ipoib_dbg_data(priv, "cm recv completion: id %d, op %d, status: %d\n",
wr_id, wc->opcode, wc->status);
@@ -383,7 +385,11 @@
}
}
- if (unlikely(ipoib_cm_alloc_rx_skb(dev, wr_id, mapping))) {
+ frags = PAGE_ALIGN(wc->byte_len - min(wc->byte_len,
+ (unsigned)IPOIB_CM_HEAD_SIZE)) / PAGE_SIZE;
+
+ newskb = ipoib_cm_alloc_rx_skb(dev, wr_id, frags, mapping);
+ if (unlikely(!newskb)) {
/*
* If we can't allocate a new RX buffer, dump
* this packet and reuse the old buffer.
@@ -393,13 +399,13 @@
goto repost;
}
- ipoib_cm_dma_unmap_rx(priv, priv->cm.srq_ring[wr_id].mapping);
- memcpy(priv->cm.srq_ring[wr_id].mapping, mapping, sizeof mapping);
+ ipoib_cm_dma_unmap_rx(priv, frags, priv->cm.srq_ring[wr_id].mapping);
+ memcpy(priv->cm.srq_ring[wr_id].mapping, mapping, (frags + 1) * sizeof *mapping);
ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
wc->byte_len, wc->slid);
- skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len);
+ skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len, newskb);
skb->protocol = ((struct ipoib_header *) skb->data)->proto;
skb->mac.raw = skb->data;
@@ -1193,7 +1199,8 @@
priv->cm.rx_wr.num_sge = IPOIB_CM_RX_SG;
for (i = 0; i < ipoib_recvq_size; ++i) {
- if (ipoib_cm_alloc_rx_skb(dev, i, priv->cm.srq_ring[i].mapping)) {
+ if (!ipoib_cm_alloc_rx_skb(dev, i, IPOIB_CM_RX_SG - 1,
+ priv->cm.srq_ring[i].mapping)) {
ipoib_warn(priv, "failed to allocate receive buffer %d\n", i);
ipoib_cm_dev_cleanup(dev);
return -ENOMEM;
@@ -1228,7 +1235,8 @@
return;
for (i = 0; i < ipoib_recvq_size; ++i)
if (priv->cm.srq_ring[i].skb) {
- ipoib_cm_dma_unmap_rx(priv, priv->cm.srq_ring[i].mapping);
+ ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
+ priv->cm.srq_ring[i].mapping);
dev_kfree_skb_any(priv->cm.srq_ring[i].skb);
priv->cm.srq_ring[i].skb = NULL;
}
