Message-ID: <4b72607d-6db1-5e53-4ee2-30a829cd12c4@nbd.name>
Date:   Tue, 14 Mar 2023 13:36:10 +0100
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Subject: Re: [PATCH] wifi: mac80211: Serialize calls to drv_wake_tx_queue()
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To:     Johannes Berg <johannes@sipsolutions.net>,
        Alexander Wetzel <alexander@wetzel-home.de>
Cc:     linux-wireless@vger.kernel.org, Thomas Mann <rauchwolke@gmx.net>,
        stable@vger.kernel.org,
        =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= <toke@toke.dk>
References: <20230313201542.72325-1-alexander@wetzel-home.de>
 <130d44bccb317cc82d57caf5b8ca1471fe0faed4.camel@sipsolutions.net>
 <55ede120-b055-e834-e617-fe3069227652@wetzel-home.de>
 <519b5bb9-8899-ae7c-4eff-f3116cdfdb56@nbd.name>
 <067780600cd56014c3c820117d139ddb1c352b28.camel@sipsolutions.net>
From:   Felix Fietkau <nbd@nbd.name>
In-Reply-To: <067780600cd56014c3c820117d139ddb1c352b28.camel@sipsolutions.net>
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On 14.03.23 13:32, Johannes Berg wrote:
> On Tue, 2023-03-14 at 13:28 +0100, Felix Fietkau wrote:
>> If you want to address this in the least invasive way, add [...],
>> a global lock to iwlwifi
>> 
> 
> I'm already fixing this, see
> https://lore.kernel.org/r/5674c40151267fea1333f0eda1701b141bbaa170.camel@sipsolutions.net
> 
>> , and a 
>> per-AC lock inside ieee80211_handle_wake_tx_queue().
> 
> I'm not *entirely* sure per AC is sufficient given that you could
> technically map two ACs to the same HW queue with vif->hw_queue[]?
> 
> But again, not really sure all that complexity is still worth it.
Per AC should be sufficient even in that case, because scheduling 
happens per AC regardless of vif hw queue mapping.

- Felix