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From:   Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
To:     Johannes Berg <johannes@sipsolutions.net>,
        Jens Axboe <axboe@kernel.dk>,
        Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>
Cc:     "linux-wireless\@vger.kernel.org" <linux-wireless@vger.kernel.org>,
        Networking <netdev@vger.kernel.org>
Subject: Re: iwlwifi warnings in 5.5-rc1
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References: <ceb74ea2-6a1b-4cef-8749-db21a2ee4311@kernel.dk> <9727368004ceef03f72d259b0779c2cf401432e1.camel@sipsolutions.net> <878snjgs5l.fsf@toke.dk> <3420d73e667b01ec64bf0cc9da6232b41e862860.camel@sipsolutions.net> <875zingnzt.fsf@toke.dk> <bfab4987668990ea8d86a98f3e87c3fa31403745.camel@sipsolutions.net> <14bbfcc8408500704c46701251546e7ff65c6fd0.camel@sipsolutions.net>
Date:   Wed, 11 Dec 2019 15:04:59 +0100
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Johannes Berg <johannes@sipsolutions.net> writes:

> Btw, there's *another* issue. You said in the commit log:
>
>     This patch does *not* include any mechanism to wake a throttled TXQ a=
gain,
>     on the assumption that this will happen anyway as a side effect of wh=
atever
>     freed the skb (most commonly a TX completion).
>
> Thinking about this some more, I'm not convinced that this assumption
> holds. You could have been stopped due to the global limit, and now you
> wake some queue but the TXQ is empty - now you should reschedule some
> *other* TXQ since the global limit had kicked in, not the per-TXQ limit,
> and prevented dequeuing, no?

Well if you hit the global limit that means you have 24ms worth of data
queued in the hardware; those should be completed in turn, and enable
more to be dequeued, no?

-Toke