From mboxrd@z Thu Jan  1 00:00:00 1970
From: Simon Guinot <simon.guinot@sequanux.org>
Subject: Re: Problems with mvneta
Date: Tue, 31 Oct 2017 18:09:38 +0100
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Cc: Sven =?utf-8?Q?M=C3=BCller?= <musv@gmx.de>,
        Andreas Tobler <andreas.tobler@cloudguard.ch>,
        =?utf-8?Q?Gr=C3=A9gory?= Clement
        <gregory.clement@free-electrons.com>,
        Antoine =?utf-8?Q?T=C3=A9nart?=
        <antoine.tenart@free-electrons.com>, netdev@vger.kernel.org,
        Marcin Wojtas <mw@semihalf.com>
To: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
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On Tue, Oct 31, 2017 at 03:27:40PM +0100, Thomas Petazzoni wrote:
> Hello,

Hi Thomas,

>=20
> Let's add Simon Guinot in the loop.
>=20
> On Tue, 31 Oct 2017 15:23:22 +0100, Sven M=C3=BCller wrote:
> > After quite a long time of trying to reproduce the issue without any su=
ccess I got 3 network crashes today. And all errors occurred with a kernel =
including the patch:=20
> >=20
> > 2a90f7e1d5d04e4f1060268e0b55a2c702bbd67a
> >=20
> > At least according to Andreas' and my problems we can exclude the 6ad2 =
patch as the source of the errors.=20
>=20
> 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.

>=20
> 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

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