The kdb trace was accurate, we could actually see the e100 ISR pop from no
where right in the middle of our ans_notify every time the TX queue would
fill up. When we commented out the call to spin_*_irqsave(), it worked fine
under heavy stress for days.
Is it possible it was something wrong with 2.4.0-test10 specifically ?
We had to drop the locks in the final release and never got around to
checking it on other kernel releases (it went on the TO_DO list ;-).
Shmulik.
-----Original Message-----
From: Andrew Morton [mailto:andrewm@uow.edu.au]
Sent: Wednesday, March 07, 2001 1:43 PM
To: Hen, Shmulik
Subject: Re: spinlock help
"Hen, Shmulik" wrote:
>
> How about if the same sequence occurred, but from two different drivers ?
>
> We've had some bad experience with this stuff. Our driver, which acts as
an
> intermediate net driver, would call the hard_start_xmit in the base
driver.
> The base driver, wanting to block receive interrupts would issue a
> 'spin_lock_irqsave(a,b)' and process the packet. If the TX queue is full,
it
> could call an indication entry point in our intermediate driver to signal
it
> to stop sending more packets. Since our indication function handles many
> types of indications but can process them only one at a time, we wanted to
> block other indications while queuing the request.
>
> The whole sequence would look like that:
>
> [our driver]
> ans_send() {
> .
> .
> e100_hard_start_xmit(dev, skb);
> .
> .
> }
>
> [e100.o]
> e100_hard_start_xmit() {
> .
> .
> spin_lock_irqsave(a,b);
> .
> .
> if(tx_queue_full)
> ans_notify(TX_QUEUE_FULL); <--
> .
> .
> spin_unlock_irqrestore(a,b);
> }
>
> [our driver]
> ans_notify() {
> .
> .
> spin_lock_irqsave(c,d);
> queue_request(req_type);
> spin_unlock_irqrestore(c,d); <--
> .
> .
> }
>
> At that point, for some reason, interrupts were back
Sorry, that can't happen.
Really, you must have made a mistake somewhere.
-
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This archive was generated by hypermail 2b29 : Wed Mar 07 2001 - 21:00:22 EST