From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH v4] net: Introduce realloc_netdev_mq() Date: Thu, 03 Dec 2009 22:29:42 +0100 Message-ID: <4B182DC6.5030800@gmail.com> References: <20091101132017.GA2598@ami.dom.local> <20091102.033533.08766686.davem@davemloft.net> <20091102123029.GA7790@ff.dom.local> <20091102.043907.236634594.davem@davemloft.net> <20091203143918.GA20526@ff.dom.local> <4B17D697.8000105@gmail.com> <20091203163640.GA2584@ami.dom.local> <20091203165449.GA2960@ami.dom.local> <4B17EFE3.4080301@gmail.com> <20091203202937.GA11436@ami.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , mchan@broadcom.com, kaber@trash.net, netdev@vger.kernel.org To: Jarek Poplawski Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:56143 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750976AbZLCV3n (ORCPT ); Thu, 3 Dec 2009 16:29:43 -0500 In-Reply-To: <20091203202937.GA11436@ami.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: Jarek Poplawski a =E9crit : > On Thu, Dec 03, 2009 at 06:05:39PM +0100, Eric Dumazet wrote: >> Jarek Poplawski a =E9crit : >>> On Thu, Dec 03, 2009 at 05:36:40PM +0100, Jarek Poplawski wrote: >>>> On Thu, Dec 03, 2009 at 04:17:43PM +0100, Eric Dumazet wrote: >>>>> if (realloc_netdev_mq(dev, real_queues)) >>>>> dev->real_num_tx_queues =3D real_queues; >>>>> >>>>> In this case the memory error is not fatal. >>>> Good point! We can consider doing this inside the function too? >>> Hmm... Of course, not exactly this - I mean using min(). >> Sure, allowing to reduce the count in case new allocation failed. >> >> And report an error if caller wanted to increase number of queues an= d allocation failed. >=20 > Hmm... After re-thinking it looks a bit too complex to me. I think, > there is no reason to not report this error since in most cases it > shouldn't be fatal. That's why I skipped this check in the changelog > example. Unless I miss something? >=20 > Thanks, > Jarek P. > ---------------> (take 4) >=20 > This patch separates allocation of TX subqueues from alloc_netdev_mq(= ) > to realloc_netdev_mq() to allow for resizing like in this example: >=20 > some_nic_probe() > { > ... > dev =3D alloc_etherdev_mq(sizeof(*bp), 1) > ... > if (MSI-X_available && device_supports_MSI-X_and_multiqueue) > realloc_netdev_mq(dev, TX_MAX_RINGS) > register_netdev(dev) > ... > } >=20 > Alternatively, it can be done in reverse order: starting from the > highest queue_count and reallocating with a lower one. >=20 > The main difference is to hold in num_tx_queues something that is > really available, instead of max possible value for all configs, in > case of drivers allocating net_device at the beginning of the probe. >=20 > The description of alloc_netdev_mq() is fixed btw. >=20 > Reported-by: Eric Dumazet > Signed-off-by: Jarek Poplawski > Cc: Eric Dumazet Nice patch, thanks :) Acked-by: Eric Dumazet