From: Heiner Kallweit <hkallweit1@gmail.com>
To: Nikolai Zhubr <zhubr.2@gmail.com>, netdev <netdev@vger.kernel.org>
Cc: Jeff Garzik <jgarzik@pobox.com>
Subject: Re: Realtek 8139 problem on 486.
Date: Mon, 31 May 2021 21:05:14 +0200 [thread overview]
Message-ID: <bf4e6e02-06ce-3001-29c8-9f0bd3f58cd8@gmail.com> (raw)
In-Reply-To: <60B514A0.1020701@gmail.com>
On 31.05.2021 18:53, Nikolai Zhubr wrote:
> Hi all,
>
> 31.05.2021 2:17, Nikolai Zhubr:
> [...]
>> However indeed, it seems a problem was introduced with a rework of
>> interrupt handling (rtl8139_interrupt) in 2.6.3, because I have already
>> pushed all other differences from 2.6.3 to 2.6.2 and it still keeps
>> working fine.
>> My resulting minimized diff is still ~300 lines, it is too big and
>> complicated to be usefull to post here as is.
>
> Some more input.
>
> I was able to minimize the problematic diff to basically one screenfull, it is quite comprehencable now, and I'm including it below. It is the change in status/event handling due to a switch to NAPI that intruduced the problem.
> Now, in some more detailed tests, I observe that _receiving_ still works fine. It is _sending_ that suffers, and apparently, only when trying to send a lot at a time. In such case I see these warnings:
>
> NETDEV WATCHDOG: eth0: transmit timed out
> eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1
>
> It looks like the queue of tx frames somehow gets messed up.
>
> The essential diff fragment:
> ================================================
> dev->open = rtl8139_open;
> dev->hard_start_xmit = rtl8139_start_xmit;
> + dev->poll = rtl8139_poll;
> dev->weight = 64;
> dev->stop = rtl8139_close;
> dev->get_stats = rtl8139_get_stats;
> @@ -2015,7 +2010,7 @@
> tp->stats.rx_bytes += pkt_size;
> tp->stats.rx_packets++;
>
> - netif_rx (skb);
> + netif_receive_skb (skb);
> } else {
> if (net_ratelimit())
> printk (KERN_WARNING
> @@ -2138,10 +2133,8 @@
> u16 status, ackstat;
> int link_changed = 0; /* avoid bogus "uninit" warning */
> int handled = 0;
> - int boguscnt = max_interrupt_work;
>
> spin_lock (&tp->lock);
> - do {
> status = RTL_R16 (IntrStatus);
>
> /* shared irq? */
> @@ -2169,8 +2162,14 @@
> if (ackstat)
> RTL_W16 (IntrStatus, ackstat);
>
> - if (netif_running (dev) && (status & RxAckBits))
> - rtl8139_rx (dev, tp, 1000000000);
> + /* Receive packets are processed by poll routine.
> + If not running start it now. */
> + if (status & RxAckBits){
> + if (netif_rx_schedule_prep(dev)) {
> + RTL_W16_F (IntrMask, rtl8139_norx_intr_mask);
> + __netif_rx_schedule (dev);
> + }
> + }
>
> /* Check uncommon events with one test. */
> if (unlikely(status & (PCIErr | PCSTimeout | RxUnderrun | RxErr)))
> @@ -2182,16 +2181,6 @@
> if (status & TxErr)
> RTL_W16 (IntrStatus, TxErr);
> }
> - boguscnt--;
> - } while (boguscnt > 0);
> -
> ================================================
>
>
> Thank you,
>
> Regards,
> Nikolai
>
>
>
>>
>>
Issue could be related to rx and tx processing now potentially running in parallel.
I only have access to the current 8139too source code, hopefully the following
works on the old version:
In the end of rtl8139_start_xmit() there's
if ((tp->cur_tx - NUM_TX_DESC) == tp->dirty_tx)
netif_stop_queue (dev);
Try changing this to
if (tp->cur_tx - NUM_TX_DESC == tp->dirty_tx) {
smp_wmb();
netif_stop_queue (dev);
smp_mb__after_atomic(); /* if this doesn't exist yet, use mb() */
if (tp->cur_tx - NUM_TX_DESC != tp->dirty_tx)
netif_start_queue(dev);
}
And at the end of rtl8139_tx_interrupt() change
if (tp->dirty_tx != dirty_tx) {
tp->dirty_tx = dirty_tx;
mb();
netif_wake_queue (dev);
}
to
if (tp->dirty_tx != dirty_tx) {
tp->dirty_tx = dirty_tx;
mb();
if (netif_queue_stopped(dev) && tp->cur_tx - NUM_TX_DESC != tp->dirty_tx)
netif_wake_queue (dev);
}
next prev parent reply other threads:[~2021-05-31 19:05 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-29 14:08 Realtek 8139 problem on 486 Nikolai Zhubr
2021-05-29 18:42 ` Heiner Kallweit
2021-05-29 21:44 ` tedheadster
2021-05-30 0:49 ` Nikolai Zhubr
2021-05-30 10:36 ` Nikolai Zhubr
2021-05-30 17:27 ` Nikolai Zhubr
2021-05-30 20:54 ` Arnd Bergmann
2021-05-30 23:17 ` Nikolai Zhubr
2021-05-31 16:53 ` Nikolai Zhubr
2021-05-31 18:39 ` Arnd Bergmann
2021-05-31 22:18 ` Nikolai Zhubr
2021-05-31 22:30 ` Heiner Kallweit
2021-06-01 7:20 ` Arnd Bergmann
2021-06-01 10:53 ` Nikolai Zhubr
2021-06-01 11:42 ` Heiner Kallweit
2021-06-01 16:09 ` Nikolai Zhubr
2021-06-01 21:48 ` Heiner Kallweit
2021-06-01 23:37 ` Nikolai Zhubr
2021-06-02 9:12 ` Arnd Bergmann
2021-06-07 23:07 ` Nikolai Zhubr
2021-06-08 7:44 ` Arnd Bergmann
2021-06-08 20:32 ` Nikolai Zhubr
2021-06-08 20:45 ` Arnd Bergmann
2021-06-08 22:07 ` Nikolai Zhubr
2021-06-09 7:09 ` Arnd Bergmann
2021-06-12 17:40 ` Nikolai Zhubr
2021-06-12 22:41 ` Arnd Bergmann
2021-06-13 14:10 ` Nikolai Zhubr
2021-06-13 21:52 ` Arnd Bergmann
2021-06-03 18:32 ` Maciej W. Rozycki
2021-06-04 7:36 ` Arnd Bergmann
2021-06-20 0:34 ` Thomas Gleixner
2021-06-20 10:19 ` Arnd Bergmann
2021-06-21 4:10 ` Maciej W. Rozycki
2021-06-21 11:22 ` Arnd Bergmann
2021-06-21 14:42 ` Maciej W. Rozycki
2021-06-21 15:20 ` Arnd Bergmann
2021-06-22 11:12 ` David Laight
2021-06-22 12:42 ` Nikolai Zhubr
2021-06-22 13:22 ` Arnd Bergmann
2021-06-22 18:42 ` Nikolai Zhubr
2021-06-22 19:26 ` Arnd Bergmann
2021-06-23 1:04 ` Maciej W. Rozycki
2021-06-24 17:56 ` Nikolai Zhubr
2021-06-24 18:25 ` Maciej W. Rozycki
2021-07-14 23:32 ` Maciej W. Rozycki
2021-07-15 7:32 ` Nikolai Zhubr
2021-07-16 23:48 ` Maciej W. Rozycki
2021-06-23 16:31 ` Nikolai Zhubr
2021-06-23 23:39 ` Maciej W. Rozycki
2021-06-24 8:28 ` Arnd Bergmann
2021-07-02 19:02 ` Nikolai Zhubr
2021-07-03 9:10 ` Arnd Bergmann
2021-07-08 19:21 ` Nikolai Zhubr
2021-07-09 7:31 ` Arnd Bergmann
2021-07-09 12:43 ` David Laight
2021-06-01 17:44 ` Maciej W. Rozycki
2021-06-02 15:14 ` Nikolai Zhubr
2021-06-02 15:28 ` Arnd Bergmann
2021-05-31 19:05 ` Heiner Kallweit [this message]
2021-05-31 18:29 ` Denis Kirjanov
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