From: Jesse Brandeburg <jesse.brandeburg@intel.com>
Date: Wed, 27 Oct 2021 12:38:36 -0700
Subject: ice: use prefetch methods
Patch-mainline: v5.17-rc1
Git-commit: cc14db11c8a40f930fc1e4b254a37e0fce745236
References: jsc#PED-376

The kernel provides some prefetch mechanisms to speed up commonly
cold cache line accesses during receive processing. Since these are
software structures it helps to have these strategically placed
prefetches.

Be careful to call BQL prefetch complete only for non XDP queues.

Co-developed-by: Piotr Raczynski <piotr.raczynski@intel.com>
Signed-off-by: Piotr Raczynski <piotr.raczynski@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/ice/ice_txrx.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -3,8 +3,9 @@
 
 /* The driver transmit and receive code */
 
-#include <linux/prefetch.h>
 #include <linux/mm.h>
+#include <linux/netdevice.h>
+#include <linux/prefetch.h>
 #include <linux/bpf_trace.h>
 #include <net/dsfield.h>
 #include <net/xdp.h>
@@ -219,6 +220,10 @@ static bool ice_clean_tx_irq(struct ice_
 	struct ice_tx_desc *tx_desc;
 	struct ice_tx_buf *tx_buf;
 
+	/* get the bql data ready */
+	if (!ice_ring_is_xdp(tx_ring))
+		netdev_txq_bql_complete_prefetchw(txring_txq(tx_ring));
+
 	tx_buf = &tx_ring->tx_buf[i];
 	tx_desc = ICE_TX_DESC(tx_ring, i);
 	i -= tx_ring->count;
@@ -232,6 +237,9 @@ static bool ice_clean_tx_irq(struct ice_
 		if (!eop_desc)
 			break;
 
+		/* follow the guidelines of other drivers */
+		prefetchw(&tx_buf->skb->users);
+
 		smp_rmb();	/* prevent any other reads prior to eop_desc */
 
 		ice_trace(clean_tx_irq, tx_ring, tx_desc, tx_buf);
@@ -2272,6 +2280,9 @@ ice_xmit_frame_ring(struct sk_buff *skb,
 		return NETDEV_TX_BUSY;
 	}
 
+	/* prefetch for bql data which is infrequently used */
+	netdev_txq_bql_enqueue_prefetchw(txring_txq(tx_ring));
+
 	offload.tx_ring = tx_ring;
 
 	/* record the location of the first descriptor for this packet */