Messages in this thread | | | Date | Tue, 19 Aug 2008 15:58:45 -0700 (PDT) | Subject | Re: [PATCH] atl1: disable TSO by default | From | David Miller <> |
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From: Jay Cliburn <jacliburn@bellsouth.net> Date: Tue, 19 Aug 2008 17:53:34 -0500
> On Tue, 19 Aug 2008 23:10:37 +1000 > Herbert Xu <herbert@gondor.apana.org.au> wrote: > > > Jay Cliburn <jacliburn@bellsouth.net> wrote: > > > > netdev->features |= NETIF_F_LLTX; > > > > Another new driver using LLTX, this is not good when we're trying > > to get rid of it. > > The atl1 driver was merged in the spring of 2007, so I'm not sure I > consider it new (but your kernel development time horizon is undoubtedly > *way* longer than mine, so you may indeed consider it new). It was > basically a vendor driver that we modified to conform to kernel coding > standards. It started life, we believe, as pretty much a clone of the > e1000 driver circa 2005, so that's likely where it's use of LLTX > came from.
You'll have to forgive us, as we often have a knee jerk reaction to seeing LLTX anywhere :-)
> > Perhaps we could just kill it by ignoring the LLTX flag and always > > grabbing the xmit lock. That should be safe as long as none of these > > drivers grab the xmit lock within their private locks. > > I'd be happy to gin up a patch if you could point me to a driver that > implements properly what you're asking.
TG3 is a good example, but that's just my heavily slanted opinion.
What your work should amount to is:
1) Eliminate local driver TX spinlock.
2) Stop taking #1 in ->hard_start_xmit()
3) Where you take #1 elsewhere, replace with netif_tx_lock() and friends.
4) Stop setting NETIF_F_LLTX.
That should do it, but of course there are usually other details.
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