Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3EBFC10F13 for ; Tue, 16 Apr 2019 08:37:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7F3CD2073F for ; Tue, 16 Apr 2019 08:37:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728313AbfDPIhp (ORCPT ); Tue, 16 Apr 2019 04:37:45 -0400 Received: from s3.sipsolutions.net ([144.76.43.62]:56142 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726576AbfDPIhp (ORCPT ); Tue, 16 Apr 2019 04:37:45 -0400 Received: by sipsolutions.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1hGJaz-0003Fv-As; Tue, 16 Apr 2019 10:37:37 +0200 Message-ID: Subject: Re: [PATCH 5/5] mac80211: set NETIF_F_LLTX when using intermediate tx queues From: Johannes Berg To: Herbert Xu , Arend Van Spriel Cc: Toke =?ISO-8859-1?Q?H=F8iland-J=F8rgensen?= , Felix Fietkau , linux-wireless@vger.kernel.org Date: Tue, 16 Apr 2019 10:37:34 +0200 In-Reply-To: <20190416083636.5ttvezqyhzr2worg@gondor.apana.org.au> References: <20190316170634.13125-1-nbd@nbd.name> <20190316170634.13125-5-nbd@nbd.name> <87sgvmvg9g.fsf@toke.dk> <773e4dff-29fd-22b4-e4bc-cd5a94c66dc2@broadcom.com> <20190416074444.pdubbh6fbibdnhi7@gondor.apana.org.au> <73b18131-2777-da5c-a6ee-9d9b3e13cd06@broadcom.com> <20190416083636.5ttvezqyhzr2worg@gondor.apana.org.au> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-2.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org 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. johannes