From: jan <jan@openbsd.org>
Date: Mon, 10 Jul 2023 19:36:54 +0000 (+0000)
Subject: ix(4): allocate less memory for tx buffers
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=40336254e8d345d7c915f9161674e61646a68517;p=openbsd

ix(4): allocate less memory for tx buffers

TSO packets are limited to MAXMCLBYTES (64k).  Thus, we don't need to
allocate IXGBE_TSO_SIZE (256k) per packet for the transmit buffers.

tested by bluhm

ok bluhm@
---

diff --git a/sys/dev/pci/if_ix.c b/sys/dev/pci/if_ix.c
index 195b5d63895..92b384bb7e0 100644
--- a/sys/dev/pci/if_ix.c
+++ b/sys/dev/pci/if_ix.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ix.c,v 1.198 2023/07/08 09:01:30 jmatthew Exp $	*/
+/*	$OpenBSD: if_ix.c,v 1.199 2023/07/10 19:36:54 jan Exp $	*/
 
 /******************************************************************************
 
@@ -37,6 +37,12 @@
 #include <dev/pci/if_ix.h>
 #include <dev/pci/ixgbe_type.h>
 
+/*
+ * Our TCP/IP Stack could not handle packets greater than MAXMCLBYTES.
+ * This interface could not handle packets greater than IXGBE_TSO_SIZE.
+ */
+CTASSERT(MAXMCLBYTES <= IXGBE_TSO_SIZE);
+
 /*********************************************************************
  *  Driver version
  *********************************************************************/
@@ -2263,7 +2269,7 @@ ixgbe_allocate_transmit_buffers(struct tx_ring *txr)
 	/* Create the descriptor buffer dma maps */
 	for (i = 0; i < sc->num_tx_desc; i++) {
 		txbuf = &txr->tx_buffers[i];
-		error = bus_dmamap_create(txr->txdma.dma_tag, IXGBE_TSO_SIZE,
+		error = bus_dmamap_create(txr->txdma.dma_tag, MAXMCLBYTES,
 			    sc->num_segs, PAGE_SIZE, 0,
 			    BUS_DMA_NOWAIT, &txbuf->map);