netdev - Re: [PATCH net] virtio-net: suppress bad irq warning for tx napi

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Message-Id: <20210412.161458.652699519749470159.davem@davemloft.net>
Date:   Mon, 12 Apr 2021 16:14:58 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     mst@...hat.com
Cc:     weiwan@...gle.com, netdev@...r.kernel.org, kuba@...nel.org,
        willemb@...gle.com, virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH net] virtio-net: suppress bad irq warning for tx napi

From: "Michael S. Tsirkin" <mst@...hat.com>
Date: Mon, 12 Apr 2021 18:33:45 -0400

> On Mon, Apr 12, 2021 at 06:08:21PM -0400, Michael S. Tsirkin wrote:
>> OK I started looking at this again. My idea is simple.
>> A. disable callbacks before we try to drain skbs
>> B. actually do disable callbacks even with event idx
>> 
>> To make B not regress, we need to
>> C. detect the common case of disable after event triggering and skip the write then.
>> 
>> I added a new event_triggered flag for that.
>> Completely untested - but then I could not see the warnings either.
>> Would be very much interested to know whether this patch helps
>> resolve the sruprious interrupt problem at all ...
>> 
>> 
>> Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
> 
> Hmm a slightly cleaner alternative is to clear the flag when enabling interrupts ...
> I wonder which cacheline it's best to use for this.
> 
> Signed-off-by: Michael S. Tsirkin <mst@...hat.com>

Please make a fresh new submission if you want to use this approach, thanks.