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Message-ID: <79161904-1e56-3046-b381-705e4af11e84@wetzel-home.de>
Date:   Fri, 30 Sep 2022 11:08:28 +0200
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Subject: Re: [PATCH] wifi: mac80211: Use internal TX queues for all drivers
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To:     Johannes Berg <johannes@sipsolutions.net>,
        linux-wireless@vger.kernel.org
References: <20220926161303.13035-1-alexander@wetzel-home.de>
 <da810136f6cf0608167cc8297ce73d11b83974d6.camel@sipsolutions.net>
From:   Alexander Wetzel <alexander@wetzel-home.de>
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On 29.09.22 22:40, Johannes Berg wrote:
> Thanks for doing this!
> 
> It's a bit bad timing right now, so I'll only have a chance to look at
> this in the next couple of weeks, but that also doesn't matter that much
> since 6.0 release is imminent (will likely be Sunday).
> 

Thanks for the warning. I'll then send a v2 to correct skb_get_hash() 
handling in the next days.

> Just wanted to comment on this one thing for now:
> 
> On Mon, 2022-09-26 at 18:13 +0200, Alexander Wetzel wrote:
>> A short look at the in-tree drivers seems to confirm, that mac80211
>> drivers are indeed not directly calling netif_stop_queue(). Which is no
>> longer undesired but outright wrong after this patch.
>> So I *think* we should be fine on that front, too.
>>
> 
> They really couldn't, they don't have (easy) access to the netdev. There
> are ways of getting to the netdev, but they're (intentionally) difficult
> and doing that would've been wrong even previously since mac80211 has
> its own reasons for stopping netdev queues sometimes.
> 
> So unless a driver is already broken, this can't be an issue.
> 
>> I did not try very hard to identify now obsolete code fragments and
>> kept this as simple as possible.
> 
> That's nice enough for now, do you want to do follow-ups to clean up
> more?
> 

The general plan so far is, to move everything to iTXQ first and then 
see what we an throw out. I'll prepare a patch cleaning up that a bit 
more. Don't think that will be much at this stage, so maybe I just add 
that into the v2 of the patch...

I'm basically working with the plan you outlined some years ago:
https://lore.kernel.org/linux-wireless/1507217947.2387.60.camel@sipsolutions.net/

It just turned out to be simpler to start with unifying the TX paths.

>> I've also have a rough draft to move PS (multicast and unicast) to iTXQ
>> we should look at later. That seems to be way more invasive than what we
>> do here. But once PS also has been sorted out moving everything to iTXQ
>> should be straight forward.
> 
> Ohhh! I'm excited about this :-)
>  > johannes

Alexander