netdev - Re: [PATCH 2/4] virtio_net: return NETDEV_TX_BUSY instead of queueing an extra skb.

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]

Date:	Mon, 22 Jun 2009 11:16:03 +0530
From:	Krishna Kumar2 <krkumar2@...ibm.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	David Miller <davem@...emloft.net>,
	Matt Carlson <mcarlson@...adcom.com>, netdev@...r.kernel.org,
	Rusty Russell <rusty@...tcorp.com.au>,
	virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 2/4] virtio_net: return NETDEV_TX_BUSY instead of	queueing an
 extra skb.

Hi Herbert,

> Herbert Xu <herbert@...dor.apana.org.au> wrote on 06/19/2009 10:06:13 AM:
>
> > We either remove the API, or fix it.  I think fixing it is better,
because my
> > driver will be simpler and it's obvious noone wants to rewrite 50
drivers and
> > break several of them.
>
> My preference is obviously in the long term removal of TX_BUSY.
> Due to resource constraints that cannot be done immediately.  So
> at least we should try to stop its proliferation.
>
> BTW removing TX_BUSY does not mean that your driver has to stay
> complicated.  As I have said repeatedly your driver should be
> checking the stop-queue condition after transmission, not before.
>
> In fact queueing it in the driver is just as bad as return TX_BUSY!

I was curious about "queueing it in the driver" part: why is this bad? Do
you
anticipate any performance problems, or does it break QoS, or something
else I
have missed?

thanks,

- KK

--
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