From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anton Vorontsov Subject: Re: [PATCH v2] netpoll: Introduce netpoll_carrier_timeout kernel option Date: Wed, 8 Jul 2009 16:23:17 +0400 Message-ID: <20090708122317.GA7837@oksana.dev.rtsoft.ru> References: <20090708010030.GA26331@oksana.dev.rtsoft.ru> <20090707180354.2f203648@nehalam> <20090708013011.GA30330@oksana.dev.rtsoft.ru> <20090708105902.GB6000@hmsreliant.think-freely.org> Reply-To: avorontsov@ru.mvista.com Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Stephen Hemminger , David Miller , netdev@vger.kernel.org To: Neil Horman Return-path: Received: from ru.mvista.com ([213.79.90.228]:46037 "EHLO buildserver.ru.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1755907AbZGHMXT (ORCPT ); Wed, 8 Jul 2009 08:23:19 -0400 Content-Disposition: inline In-Reply-To: <20090708105902.GB6000@hmsreliant.think-freely.org> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jul 08, 2009 at 06:59:02AM -0400, Neil Horman wrote: [...] > > 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. There are other module options described in the kernel-parameters.txt. Plus it's really a kernel parameter. ;-) > > > > +#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. The earlier you bring the interface up, the earlier you'll able to catch kernel oopses. netconsole is quite useful when you don't have serial ports. The same applies for KGDBoE -- you might want to start debugging the kernel as soon as possible. Sure, netconsole starts at module_init(), but looking at my dmesg, netconsole initialization starts closer to the top of the log, so it'll catch > 60% of oopses, i.e. all oopses in subsystems that are below net/ in drivers/Makefile. Thanks, -- Anton Vorontsov email: cbouatmailru@gmail.com irc://irc.freenode.net/bd2