From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v3 1/2] net: sched: make default fifo qdiscs appear in the dump Date: Sun, 12 Mar 2017 22:53:26 -0700 (PDT) Message-ID: <20170312.225326.432231730454919673.davem@davemloft.net> References: Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: stephen@networkplumber.org, eric.dumazet@gmail.com, jhs@mojatatu.com, phil@nwl.cc, xiyou.wangcong@gmail.com, daniel@iogearbox.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jiri@resnulli.us To: jikos@kernel.org Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:52610 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751610AbdCMFxa (ORCPT ); Mon, 13 Mar 2017 01:53:30 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: From: Jiri Kosina Date: Wed, 8 Mar 2017 16:03:32 +0100 (CET) > From: Jiri Kosina > > The original reason [1] for having hidden qdiscs (potential scalability > issues in qdisc_match_from_root() with single linked list in case of large > amount of qdiscs) has been invalidated by 59cc1f61f0 ("net: sched: convert > qdisc linked list to hashtable"). > > This allows us for bringing more clarity and determinism into the dump by > making default pfifo qdiscs visible. > > We're not turning this on by default though, at it was deemed [2] too > intrusive / unnecessary change of default behavior towards userspace. > Instead, TCA_DUMP_INVISIBLE netlink attribute is introduced, which allows > applications to request complete qdisc hierarchy dump, including the > ones that have always been implicit/invisible. > > Singleton noop_qdisc stays invisible, as teaching the whole infrastructure > about singletons would require quite some surgery with very little gain > (seeing no qdisc or seeing noop qdisc in the dump is probably setting > the same user expectation). > > [1] http://lkml.kernel.org/r/1460732328.10638.74.camel@edumazet-glaptop3.roam.corp.google.com > [2] http://lkml.kernel.org/r/20161021.105935.1907696543877061916.davem@davemloft.net > > Signed-off-by: Jiri Kosina Applied, thanks Jiri.