From: Stephen Hemminger <shemminger@vyatta•com>
To: Sven Joachim <svenjoac@gmx•de>
Cc: davem@davemloft•net, netdev@vger•kernel.org
Subject: [PATCH net-next] sky2: enforce minimum ring size
Date: Thu, 17 Nov 2011 16:37:23 -0800 [thread overview]
Message-ID: <20111117163723.67964841@nehalam.linuxnetplumber.net> (raw)
In-Reply-To: <874ny2bgqa.fsf@turtle.gmx.de>
The hardware has a restriction that the minimum ring size possible
is 128. The number of elements used is controlled by tx_pending and
the overall number of elements in the ring tx_ring_size, therefore it
is okay to limit the number of elements in use to a small value (63)
but still provide a bigger ring.
Signed-off-by: Stephen Hemminger <shemminger@vyatta•com>
--- a/drivers/net/ethernet/marvell/sky2.c 2011-11-17 16:25:40.079898621 -0800
+++ b/drivers/net/ethernet/marvell/sky2.c 2011-11-17 16:33:19.088438709 -0800
@@ -4092,6 +4092,16 @@ static int sky2_set_coalesce(struct net_
return 0;
}
+/*
+ * Hardware is limited to min of 128 and max of 2048 for ring size
+ * and rounded up to next power of two
+ * to avoid division in modulus calclation
+ */
+static unsigned long roundup_ring_size(unsigned long pending)
+{
+ return max(128ul, roundup_pow_of_two(pending+1));
+}
+
static void sky2_get_ringparam(struct net_device *dev,
struct ethtool_ringparam *ering)
{
@@ -4119,7 +4129,7 @@ static int sky2_set_ringparam(struct net
sky2->rx_pending = ering->rx_pending;
sky2->tx_pending = ering->tx_pending;
- sky2->tx_ring_size = roundup_pow_of_two(sky2->tx_pending+1);
+ sky2->tx_ring_size = roundup_ring_size(sky2->tx_pending);
return sky2_reattach(dev);
}
@@ -4714,7 +4724,7 @@ static __devinit struct net_device *sky2
spin_lock_init(&sky2->phy_lock);
sky2->tx_pending = TX_DEF_PENDING;
- sky2->tx_ring_size = roundup_pow_of_two(TX_DEF_PENDING+1);
+ sky2->tx_ring_size = roundup_ring_size(TX_DEF_PENDING);
sky2->rx_pending = RX_DEF_PENDING;
hw->dev[port] = dev;
next prev parent reply other threads:[~2011-11-18 0:37 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-16 23:42 [PATCH 0/6] sky2 patches for net-next Stephen Hemminger
2011-11-16 23:42 ` [PATCH 1/6] sky2: fix hang on shutdown (and other irq issues) Stephen Hemminger
2011-11-17 8:46 ` Sven Joachim
2011-11-17 17:01 ` Stephen Hemminger
2011-11-17 18:37 ` Sven Joachim
2011-11-17 19:18 ` Stephen Hemminger
2011-11-17 20:57 ` Sven Joachim
2011-11-18 0:37 ` [PATCH net-next] sky2: fix hang in napi_disable Stephen Hemminger
2011-11-18 1:52 ` David Miller
2011-11-18 2:10 ` Stephen Hemminger
2011-11-18 2:15 ` David Miller
2011-11-18 2:44 ` David Miller
2011-11-16 23:42 ` [PATCH 2/6] sky2: pci posting issues Stephen Hemminger
2011-11-16 23:42 ` [PATCH 3/6] sky2: rename up/down functions Stephen Hemminger
2011-11-16 23:42 ` [PATCH 4/6] sky2: reduce default Tx ring size Stephen Hemminger
2011-11-17 21:07 ` Sven Joachim
2011-11-17 22:41 ` Stephen Hemminger
2011-11-18 0:37 ` Stephen Hemminger [this message]
2011-11-18 2:44 ` [PATCH net-next] sky2: enforce minimum " David Miller
2011-11-16 23:42 ` [PATCH 5/6] sky2: used fixed RSS key Stephen Hemminger
2011-11-16 23:43 ` [PATCH 6/6] sky2: version 1.30 Stephen Hemminger
2011-11-17 1:36 ` [PATCH 0/6] sky2 patches for net-next David Miller
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