Subject: Re: Problems with mvneta

From: Simon Guinot <[email-masked]>
Date: Tue, 31 Oct 2017 18:09:38 +0100

On Tue, Oct 31, 2017 at 03:27:40PM +0100, Thomas Petazzoni wrote:
> Hello,

Hi Thomas,

> 
> Let's add Simon Guinot in the loop.
> 
> On Tue, 31 Oct 2017 15:23:22 +0100, Sven Müller wrote:
> > After quite a long time of trying to reproduce the issue without any success I got 3 network crashes today. And all errors occurred with a kernel including the patch: 
> > 
> > 2a90f7e1d5d04e4f1060268e0b55a2c702bbd67a
> > 
> > At least according to Andreas' and my problems we can exclude the 6ad2 patch as the source of the errors. 
> 
> Simon, 2a90f7e1d5d04e4f1060268e0b55a2c702bbd67a is your commit, adding
> xmit_more support, and a number of people are reporting stability
> issues with this patch applied.

I wrote an earlier version of this patch. But I think this commit has
been modified by the submitter Marcin Wojtas because I don't remember
anything about the maximum number of descriptors allowed to be flush.

> 
> Do you think you will have some time to look into this ?

No I don't have time to look into that.

But after a quick look, I wonder what is happening if
"txq->pending + frags > MVNETA_TXQ_DEC_SENT_MASK" ? Because IIUC
mvneta_txq_pend_desc_add() is called anyway. And according to the
comment inside the function, it assumes there is less than 255
descriptors to send... It looks suspect.

Simon