netdev - RE: [PATCH 2/3] NET: [CORE] Stack changes to add multiqueue hardware support API

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <D5C1322C3E673F459512FB59E0DDC329031F07E6@orsmsx414.amr.corp.intel.com>
Date:	Thu, 28 Jun 2007 14:11:11 -0700
From:	"Waskiewicz Jr, Peter P" <peter.p.waskiewicz.jr@...el.com>
To:	"Patrick McHardy" <kaber@...sh.net>,
	"Jeff Garzik" <jeff@...zik.org>
Cc:	<davem@...emloft.net>, <netdev@...r.kernel.org>,
	"Kok, Auke-jan H" <auke-jan.h.kok@...el.com>, <hadi@...erus.ca>
Subject: RE: [PATCH 2/3] NET: [CORE] Stack changes to add multiqueue hardware support API

> -----Original Message-----
> From: Patrick McHardy [mailto:kaber@...sh.net] 
> Sent: Thursday, June 28, 2007 12:37 PM
> To: Jeff Garzik
> Cc: Waskiewicz Jr, Peter P; davem@...emloft.net; 
> netdev@...r.kernel.org; Kok, Auke-jan H; hadi@...erus.ca
> Subject: Re: [PATCH 2/3] NET: [CORE] Stack changes to add 
> multiqueue hardware support API
> 
> Jeff Garzik wrote:
> > Patrick McHardy wrote:
> > 
> >> Yes, but there are users that don't go through qdiscs, 
> like netpoll, 
> >> Having them check the QDISC_RUNNING bit seems ugly.
> > 
> > 
> > Is netpoll the only such user?
> 
> I'm not sure, I just remembered that one :)
> 
> Looking at Peter's multiqueue patch, which should include all 
> hard_start_xmit users (I'm not seeing sch_teql though, 
> Peter?) the only other one is pktgen.

Ugh.  That is another netif_queue_stopped() that needs
netif_subqueue_stopped().  I can send an updated patch for the core to
fix this based from your patches Patrick.

> 
> > netpoll tends to be a special case in every sense of the 
> word, and I 
> > wish it was less so :/
> 
> Indeed.

So what do we do about netpoll then wrt netif_(sub)queue_stopped() being
removed from qdisc_restart()?  The fallout of having netpoll() cause a
queue to stop (queue 0 only) is the skb sent will be requeued, since the
driver will return NETIF_TX_BUSY if this actually happens.  But this is
a corner case, and we won't lose packets; we'll just have increased
latency on that queue.  Should I worry about this or just move forward
with the sch_teql.c change and repost the core patch?

Thanks,
-PJ Waskiewicz
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html