From: Arend Van Spriel <arend.vanspriel@broadcom.com>
To: Johannes Berg <johannes@sipsolutions.net>,
Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Felix Fietkau" <nbd@nbd.name>,
linux-wireless@vger.kernel.org
Subject: Re: [PATCH 5/5] mac80211: set NETIF_F_LLTX when using intermediate tx queues
Date: Tue, 16 Apr 2019 11:17:53 +0200 [thread overview]
Message-ID: <cd0715bb-b75c-63b0-0ae4-858d14afd500@broadcom.com> (raw)
In-Reply-To: <eab39dd804405854997e50102f3d0ff925feb8d2.camel@sipsolutions.net>
On 4/16/2019 10:37 AM, Johannes Berg wrote:
> On Tue, 2019-04-16 at 16:36 +0800, Herbert Xu wrote:
>> On Tue, Apr 16, 2019 at 10:04:24AM +0200, Arend Van Spriel wrote:
>>>
>>> I was just writing up an email clarifying my question. But let me summarize
>>> this email thread. The patch from Felix adds this flag in mac80211 for
>>> drivers that indicate to support pulling packets from the internal TXQ in
>>> mac80211. I found it is deprecated, but as Felix mentioned it is used in
>>> various parts of the network subsystem, ie. batman-adv, bridge, vlan, tunnel
>>> implementations. So its use seems to be restricted rather than deprecated.
>>> Given your response above I guess my question would be to get details about
>>> what you call "proper design" as I think you are saying with that it is not
>>> needed, right?
>>
>> Essentially the only time it would be OK to use LLTX in its current
>> form is if you have no TX queue/congestion feedback which is clearly
>> not the case with wireless drivers.
>
> It is true because we have an entire buffering layer in mac80211 (in
> this case at least) and never push back to the stack.
Ok, so the crux is the "never push back to the stack" part? Well, the
internal TXQ and how that is used is obviously enabling that ;-)
Regards,
Arend
next prev parent reply other threads:[~2019-04-16 9:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-16 17:06 [PATCH 1/5] mac80211: mesh: drop redundant rcu_read_lock/unlock calls Felix Fietkau
2019-03-16 17:06 ` [PATCH 2/5] mac80211: fix memory accounting with A-MSDU aggregation Felix Fietkau
2019-03-16 18:12 ` Toke Høiland-Jørgensen
2019-03-16 17:06 ` [PATCH 3/5] mac80211: calculate hash for fq without holding fq->lock in itxq enqueue Felix Fietkau
2019-03-16 18:13 ` Toke Høiland-Jørgensen
2019-03-16 17:06 ` [PATCH 4/5] mac80211: run late dequeue late tx handlers without holding fq->lock Felix Fietkau
2019-03-16 18:13 ` Toke Høiland-Jørgensen
2022-12-05 9:46 ` Wen Gong
2022-12-07 6:30 ` Wen Gong
2022-12-12 8:31 ` Wen Gong
2019-03-16 17:06 ` [PATCH 5/5] mac80211: set NETIF_F_LLTX when using intermediate tx queues Felix Fietkau
2019-03-16 18:14 ` Toke Høiland-Jørgensen
2019-04-14 9:44 ` Arend Van Spriel
2019-04-14 11:19 ` Felix Fietkau
2019-04-14 12:34 ` Arend Van Spriel
2019-04-16 7:34 ` Arend Van Spriel
2019-04-16 7:44 ` Herbert Xu
2019-04-16 8:04 ` Arend Van Spriel
2019-04-16 8:36 ` Herbert Xu
2019-04-16 8:37 ` Johannes Berg
2019-04-16 9:17 ` Arend Van Spriel [this message]
2019-04-16 9:29 ` Herbert Xu
2019-04-16 9:33 ` Toke Høiland-Jørgensen
2019-04-16 9:33 ` Johannes Berg
2019-04-16 9:37 ` Herbert Xu
2019-04-16 9:39 ` Johannes Berg
2019-04-16 10:02 ` Toke Høiland-Jørgensen
2019-04-17 2:11 ` Herbert Xu
2019-04-17 8:28 ` Toke Høiland-Jørgensen
2019-04-16 13:13 ` Herbert Xu
2019-04-16 13:18 ` Toke Høiland-Jørgensen
2019-04-17 3:38 ` Herbert Xu
2019-04-17 9:09 ` Toke Høiland-Jørgensen
2019-04-17 9:16 ` Arend Van Spriel
2019-04-17 9:17 ` Toke Høiland-Jørgensen
2019-04-23 12:41 ` Johannes Berg
2019-04-25 8:35 ` Herbert Xu
2019-04-25 8:39 ` Johannes Berg
2019-04-25 8:44 ` Herbert Xu
2019-04-25 8:49 ` Johannes Berg
2019-04-16 19:13 ` Johannes Berg
2019-04-17 2:13 ` Herbert Xu
2019-04-16 9:38 ` Toke Høiland-Jørgensen
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