Current Netpoll init does not trust carrier detected
right upon bringing the NIC up and waits for a delay
before allowing boot to continue.
The delay varied with the kernel version:
10 seconds in 2.6.11
3 seconds in 2.6.12
4 seconds in 2.6.13 and later
Any significant delay is undesired in production
environments as 3 seconds boot the entire kernel.
The patch reduces the delay to about 300msec +
NIC startup time.
The adjusted timeout mechanism polls the carrier every 100ms
and polls for a good carrier for N_CARRIER_POLL (3)
_consecutive_ cycles or 10s maximum.
The patch is in use on a dozen x86 systems with 2.6.11
since June.
Signed-off-by: Michael Frank <[EMAIL PROTECTED]>
---
netpoll.c | 54 +++++++++++++++++++++++++++++++-----------------------
1 file changed, 31 insertions(+), 23 deletions(-)
Patch file: netp-timeout-mhfp16
--- linux-2.6.15-rc2-mhf260/net/core/netpoll.c.001 2005-11-21
08:28:58.000000000 +0100
+++ linux-2.6.15-rc2-mhf260/net/core/netpoll.c 2005-11-21 09:08:15.000000000
+0100
@@ -1,7 +1,8 @@
/*
* Common framework for low-level network console, dump, and debugger code
*
- * Sep 8 2003 Matt Mackall <[EMAIL PROTECTED]>
+ * Sep 8 2003 Matt Mackall <[EMAIL PROTECTED]>
+ * Jun 13 2005 Michael Frank <[EMAIL PROTECTED]> Adjust carrier timeout logic
*
* based on the netconsole code from:
*
@@ -69,6 +70,8 @@
(MAX_UDP_CHUNK + sizeof(struct udphdr) + \
sizeof(struct iphdr) + sizeof(struct ethhdr))
+#define N_CARRIER_POLL 3
+
static void zap_completion_queue(void);
static void queue_process(void *p)
@@ -673,6 +676,7 @@
if (!netif_running(ndev)) {
unsigned long atmost, atleast;
+ int pollcarrier;
printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
np->name, np->dev_name);
@@ -686,31 +690,35 @@
}
rtnl_shunlock();
- atleast = jiffies + HZ/10;
- atmost = jiffies + 4*HZ;
- while (!netif_carrier_ok(ndev)) {
- if (time_after(jiffies, atmost)) {
- printk(KERN_NOTICE
- "%s: timeout waiting for carrier\n",
- np->name);
- break;
- }
- cond_resched();
- }
-
- /* If carrier appears to come up instantly, we don't
- * trust it and pause so that we don't pump all our
- * queued console messages into the bitbucket.
+ /* Wait for carrier:
+ * Until carrier detected for N_CARRIER_POLL
+ * consecutive 100ms intervals.
+ *
+ * At most 10s.
*/
-
- if (time_before(jiffies, atleast)) {
- printk(KERN_NOTICE "%s: carrier detect appears"
- " untrustworthy, waiting 4 seconds\n",
- np->name);
- msleep(4000);
+
+ pollcarrier = N_CARRIER_POLL;
+ atmost = jiffies + 10 * HZ;
+
+ while (pollcarrier--) {
+ atleast = jiffies + HZ / 10;
+
+ while (time_before(jiffies, atleast))
+ cond_resched();
+
+ while (!netif_carrier_ok(ndev)) {
+ pollcarrier = N_CARRIER_POLL;
+ if (time_after(jiffies, atmost)) {
+ printk(KERN_NOTICE "%s: timeout"
+ "waiting for carrier",
+ np->name);
+ goto out;
+ }
+ cond_resched();
+ }
}
}
-
+out:
if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
memcpy(np->local_mac, ndev->dev_addr, 6);
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
