From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCH v2] netpoll: Introduce netpoll_carrier_timeout kernel option Date: Wed, 8 Jul 2009 06:59:02 -0400 Message-ID: <20090708105902.GB6000@hmsreliant.think-freely.org> References: <20090708010030.GA26331@oksana.dev.rtsoft.ru> <20090707180354.2f203648@nehalam> <20090708013011.GA30330@oksana.dev.rtsoft.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stephen Hemminger , David Miller , netdev@vger.kernel.org To: Anton Vorontsov Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:46146 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751443AbZGHK7P (ORCPT ); Wed, 8 Jul 2009 06:59:15 -0400 Content-Disposition: inline In-Reply-To: <20090708013011.GA30330@oksana.dev.rtsoft.ru> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jul 08, 2009 at 05:30:11AM +0400, Anton Vorontsov wrote: > Some PHYs require longer timeouts for carrier detection, and > auto-negotiation process may take indefinite amount of time. > > It may be inconvenient to force longer timeouts for sane PHYs, > so let's introduce a kernel command line option. > > Since we're using module_param(), the option also can be > changed in runtime. > > Signed-off-by: Anton Vorontsov > --- > > On Tue, Jul 07, 2009 at 06:03:54PM -0700, Stephen Hemminger wrote: > > On Wed, 8 Jul 2009 05:00:30 +0400 > > Anton Vorontsov wrote: > > > > > Some PHYs require longer timeouts for carrier detection, and > > > auto-negotiation process may take indefinite amount of time. > > > > > > It may be inconvenient to force longer timeouts for sane PHYs, > > > so let's introduce a kernel command line option. > > > > > > Signed-off-by: Anton Vorontsov > > > --- > > > Documentation/kernel-parameters.txt | 5 +++++ > > > net/core/netpoll.c | 11 ++++++++++- > > > 2 files changed, 15 insertions(+), 1 deletions(-) > > > > A sysctl (or module option) is a less awkward interface for something > > like this. > > Right you are, and it's less code. Wasn't sure if it makes sense > to use module_param() for non-modular code, but afterall it makes > sense indeed, since with it we can change the timeout in runtime. > > > Kernel command line parameters are ugly step children > > loved only by embedded developers. > > So true! ;-) > > How about this patch? > > Thanks, > > Documentation/kernel-parameters.txt | 5 +++++ > net/core/netpoll.c | 6 +++++- > 2 files changed, 10 insertions(+), 1 deletions(-) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index d77fbd8..9347f4a 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -1531,6 +1531,11 @@ and is between 256 and 4096 characters. It is defined in the file > symbolic names: lapic and ioapic > Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic > > + netpoll.carrier_timeout= > + [NET] Specifies amount of time (in seconds) that > + netpoll should wait for a carrier. By default netpoll > + waits 4 seconds. > + I'm not sure the documentation still belongs in kernel-parameters.txt if you make this a module options, but thats just a nit. > > +#include > #include > #include > #include > @@ -50,6 +51,9 @@ static atomic_t trapped; > static void zap_completion_queue(void); > static void arp_reply(struct sk_buff *skb); > > +static unsigned int carrier_timeout = 4; > +module_param(carrier_timeout, uint, 0644); > + > static void queue_process(struct work_struct *work) > { > struct netpoll_info *npinfo = > @@ -732,7 +736,7 @@ int netpoll_setup(struct netpoll *np) > } > > atleast = jiffies + HZ/10; > - atmost = jiffies + 4*HZ; > + atmost = jiffies + carrier_timeout * HZ; > while (!netif_carrier_ok(ndev)) { > if (time_after(jiffies, atmost)) { > printk(KERN_NOTICE > -- > 1.6.3.3 > I don't mind this functionality at all, but I'm looking at the code, and I have a hard time understanding why we bring up an interface here at all. I get that we might want early netpoll access for netconsole or something like that, but looking at the console code I don't see where we buffer anything other than the standard dmesg log. I don't see much reason why we can't just let normal early interface initalization from an initramfs bring up an interface like it normally does. Neil > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >