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From: Magnus Karlsson <magnus.karlsson@gmail.com>
To: magnus.karlsson@intel.com, bjorn@kernel.org, ast@kernel.org,
	daniel@iogearbox.net, netdev@vger.kernel.org,
	maciej.fijalkowski@intel.com, ciara.loftus@intel.com
Cc: jonathan.lemon@gmail.com, bpf@vger.kernel.org,
	anthony.l.nguyen@intel.com
Subject: [PATCH bpf-next 03/13] ice: use xdp_buf instead of rx_buf for xsk zero-copy
Date: Wed, 22 Sep 2021 09:56:03 +0200	[thread overview]
Message-ID: <20210922075613.12186-4-magnus.karlsson@gmail.com> (raw)
In-Reply-To: <20210922075613.12186-1-magnus.karlsson@gmail.com>

From: Magnus Karlsson <magnus.karlsson@intel.com>

In order to use the new xsk batched buffer allocation interface, a
pointer to an array of struct xsk_buff pointers need to be provided so
that the function can put the result of the allocation there. In the
ice driver, we already have a ring that stores pointers to
xdp_buffs. This is only used for the xsk zero-copy driver and is a
union with the structure that is used for the regular non zero-copy
path. Unfortunately, that structure is larger than the xdp_buffs
pointers which mean that there will be a stride (of 20 bytes) between
each xdp_buff pointer. And feeding this into the xsk_buff_alloc_batch
interface will not work since it assumes a regular array of xdp_buff
pointers (each 8 bytes with 0 bytes in-between them on a 64-bit
system).

To fix this, remove the xdp_buff pointer from the rx_buf union and
move it one step higher to the union above which only has pointers to
arrays in it. This solves the problem and we can directly feed the SW
ring of xdp_buff pointers straight into the allocation function in the
next patch when that interface is used. This will improve performance.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_txrx.h | 16 ++-----
 drivers/net/ethernet/intel/ice/ice_xsk.c  | 56 +++++++++++------------
 2 files changed, 33 insertions(+), 39 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
index 1e46e80f3d6f..7c2328529ff8 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.h
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
@@ -164,17 +164,10 @@ struct ice_tx_offload_params {
 };
 
 struct ice_rx_buf {
-	union {
-		struct {
-			dma_addr_t dma;
-			struct page *page;
-			unsigned int page_offset;
-			u16 pagecnt_bias;
-		};
-		struct {
-			struct xdp_buff *xdp;
-		};
-	};
+	dma_addr_t dma;
+	struct page *page;
+	unsigned int page_offset;
+	u16 pagecnt_bias;
 };
 
 struct ice_q_stats {
@@ -270,6 +263,7 @@ struct ice_ring {
 	union {
 		struct ice_tx_buf *tx_buf;
 		struct ice_rx_buf *rx_buf;
+		struct xdp_buff **xdp_buf;
 	};
 	/* CL2 - 2nd cacheline starts here */
 	u16 q_index;			/* Queue number of ring */
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index 5a9f61deeb38..f4ab5259a56c 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -364,7 +364,7 @@ bool ice_alloc_rx_bufs_zc(struct ice_ring *rx_ring, u16 count)
 {
 	union ice_32b_rx_flex_desc *rx_desc;
 	u16 ntu = rx_ring->next_to_use;
-	struct ice_rx_buf *rx_buf;
+	struct xdp_buff **xdp;
 	bool ok = true;
 	dma_addr_t dma;
 
@@ -372,26 +372,26 @@ bool ice_alloc_rx_bufs_zc(struct ice_ring *rx_ring, u16 count)
 		return true;
 
 	rx_desc = ICE_RX_DESC(rx_ring, ntu);
-	rx_buf = &rx_ring->rx_buf[ntu];
+	xdp = &rx_ring->xdp_buf[ntu];
 
 	do {
-		rx_buf->xdp = xsk_buff_alloc(rx_ring->xsk_pool);
-		if (!rx_buf->xdp) {
+		*xdp = xsk_buff_alloc(rx_ring->xsk_pool);
+		if (!xdp) {
 			ok = false;
 			break;
 		}
 
-		dma = xsk_buff_xdp_get_dma(rx_buf->xdp);
+		dma = xsk_buff_xdp_get_dma(*xdp);
 		rx_desc->read.pkt_addr = cpu_to_le64(dma);
 		rx_desc->wb.status_error0 = 0;
 
 		rx_desc++;
-		rx_buf++;
+		xdp++;
 		ntu++;
 
 		if (unlikely(ntu == rx_ring->count)) {
 			rx_desc = ICE_RX_DESC(rx_ring, 0);
-			rx_buf = rx_ring->rx_buf;
+			xdp = rx_ring->xdp_buf;
 			ntu = 0;
 		}
 	} while (--count);
@@ -421,19 +421,19 @@ static void ice_bump_ntc(struct ice_ring *rx_ring)
 /**
  * ice_construct_skb_zc - Create an sk_buff from zero-copy buffer
  * @rx_ring: Rx ring
- * @rx_buf: zero-copy Rx buffer
+ * @xdp_arr: Pointer to the SW ring of xdp_buff pointers
  *
  * This function allocates a new skb from a zero-copy Rx buffer.
  *
  * Returns the skb on success, NULL on failure.
  */
 static struct sk_buff *
-ice_construct_skb_zc(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf)
+ice_construct_skb_zc(struct ice_ring *rx_ring, struct xdp_buff **xdp_arr)
 {
-	unsigned int metasize = rx_buf->xdp->data - rx_buf->xdp->data_meta;
-	unsigned int datasize = rx_buf->xdp->data_end - rx_buf->xdp->data;
-	unsigned int datasize_hard = rx_buf->xdp->data_end -
-				     rx_buf->xdp->data_hard_start;
+	struct xdp_buff *xdp = *xdp_arr;
+	unsigned int metasize = xdp->data - xdp->data_meta;
+	unsigned int datasize = xdp->data_end - xdp->data;
+	unsigned int datasize_hard = xdp->data_end - xdp->data_hard_start;
 	struct sk_buff *skb;
 
 	skb = __napi_alloc_skb(&rx_ring->q_vector->napi, datasize_hard,
@@ -441,13 +441,13 @@ ice_construct_skb_zc(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf)
 	if (unlikely(!skb))
 		return NULL;
 
-	skb_reserve(skb, rx_buf->xdp->data - rx_buf->xdp->data_hard_start);
-	memcpy(__skb_put(skb, datasize), rx_buf->xdp->data, datasize);
+	skb_reserve(skb, xdp->data - xdp->data_hard_start);
+	memcpy(__skb_put(skb, datasize), xdp->data, datasize);
 	if (metasize)
 		skb_metadata_set(skb, metasize);
 
-	xsk_buff_free(rx_buf->xdp);
-	rx_buf->xdp = NULL;
+	xsk_buff_free(xdp);
+	*xdp_arr = NULL;
 	return skb;
 }
 
@@ -521,7 +521,7 @@ int ice_clean_rx_irq_zc(struct ice_ring *rx_ring, int budget)
 	while (likely(total_rx_packets < (unsigned int)budget)) {
 		union ice_32b_rx_flex_desc *rx_desc;
 		unsigned int size, xdp_res = 0;
-		struct ice_rx_buf *rx_buf;
+		struct xdp_buff **xdp;
 		struct sk_buff *skb;
 		u16 stat_err_bits;
 		u16 vlan_tag = 0;
@@ -544,18 +544,18 @@ int ice_clean_rx_irq_zc(struct ice_ring *rx_ring, int budget)
 		if (!size)
 			break;
 
-		rx_buf = &rx_ring->rx_buf[rx_ring->next_to_clean];
-		rx_buf->xdp->data_end = rx_buf->xdp->data + size;
-		xsk_buff_dma_sync_for_cpu(rx_buf->xdp, rx_ring->xsk_pool);
+		xdp = &rx_ring->xdp_buf[rx_ring->next_to_clean];
+		(*xdp)->data_end = (*xdp)->data + size;
+		xsk_buff_dma_sync_for_cpu(*xdp, rx_ring->xsk_pool);
 
-		xdp_res = ice_run_xdp_zc(rx_ring, rx_buf->xdp);
+		xdp_res = ice_run_xdp_zc(rx_ring, *xdp);
 		if (xdp_res) {
 			if (xdp_res & (ICE_XDP_TX | ICE_XDP_REDIR))
 				xdp_xmit |= xdp_res;
 			else
-				xsk_buff_free(rx_buf->xdp);
+				xsk_buff_free(*xdp);
 
-			rx_buf->xdp = NULL;
+			*xdp = NULL;
 			total_rx_bytes += size;
 			total_rx_packets++;
 			cleaned_count++;
@@ -565,7 +565,7 @@ int ice_clean_rx_irq_zc(struct ice_ring *rx_ring, int budget)
 		}
 
 		/* XDP_PASS path */
-		skb = ice_construct_skb_zc(rx_ring, rx_buf);
+		skb = ice_construct_skb_zc(rx_ring, xdp);
 		if (!skb) {
 			rx_ring->rx_stats.alloc_buf_failed++;
 			break;
@@ -813,12 +813,12 @@ void ice_xsk_clean_rx_ring(struct ice_ring *rx_ring)
 	u16 i;
 
 	for (i = 0; i < rx_ring->count; i++) {
-		struct ice_rx_buf *rx_buf = &rx_ring->rx_buf[i];
+		struct xdp_buff **xdp = &rx_ring->xdp_buf[i];
 
-		if (!rx_buf->xdp)
+		if (!xdp)
 			continue;
 
-		rx_buf->xdp = NULL;
+		*xdp = NULL;
 	}
 }
 
-- 
2.29.0


  parent reply	other threads:[~2021-09-22  7:56 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-22  7:56 [PATCH bpf-next 00/13] xsk: i40e: ice: introduce batching for Rx buffer allocation Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 01/13] xsk: get rid of unused entry in struct xdp_buff_xsk Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 02/13] xsk: batched buffer allocation for the pool Magnus Karlsson
2021-09-22  7:56 ` Magnus Karlsson [this message]
2021-09-22  7:56 ` [PATCH bpf-next 04/13] ice: use the xsk batched rx allocation interface Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 05/13] i40e: " Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 06/13] xsk: optimize for aligned case Magnus Karlsson
2021-09-28 23:15   ` Nathan Chancellor
2021-09-29  5:52     ` Magnus Karlsson
2021-09-29 15:33   ` kernel test robot
2021-09-22  7:56 ` [PATCH bpf-next 07/13] selftests: xsk: fix missing initialization Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 08/13] selftests: xsk: put the same buffer only once in the fill ring Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 09/13] selftests: xsk: fix socket creation retry Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 10/13] selftests: xsk: introduce pacing of traffic Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 11/13] selftests: xsk: add single packet test Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 12/13] selftests: xsk: change interleaving of packets in unaligned mode Magnus Karlsson
2021-09-22  7:56 ` [PATCH bpf-next 13/13] selftests: xsk: add frame_headroom test Magnus Karlsson
2021-09-27 22:30 ` [PATCH bpf-next 00/13] xsk: i40e: ice: introduce batching for Rx buffer allocation patchwork-bot+netdevbpf

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