[581] in linux-net channel archive
Re: Corrupt skb lists with lance driver
daemon@ATHENA.MIT.EDU (Alan Cox)
Wed Jun 28 06:45:21 1995
From: iialan@iifeak.swan.ac.uk (Alan Cox)
To: gpg109@rsphy1.anu.edu.au (Paul Gortmaker)
Date: Wed, 28 Jun 1995 10:09:05 +0100 (BST)
Cc: linux-net@vger.rutgers.edu
In-Reply-To: <9506280121.AA12963@rsphy9.anu.edu.au> from "Paul Gortmaker" at Jun 28, 95 11:21:44 am
> With respect to "double lock on device queue" and "freed while locked"
> events with the lance driver:
Double lock is a bug, freed while locked is a perfectly safe and real
occurence in some cases. It simply means the driver hasn't yet done
a dev_kfree_skb() when the ack arrives for TCP and TCP wants to free the
queued (and now known to be received) frame.
> Of course, using bounce buffers for every Tx packet increases the CPU
> overhead with the extra memcpy() per Tx, but I can still Tx > 850kB/s
> via ftp, so it is far from crippled. This is probably a good workaround
> until the problem is solved properly. I will try to figure it out if
> I get the free time and nobody else does it first.
Depends vastly on your system. The extra copy will cost a lot on slower
systems or machines which have a lot of other work to do.
Alan
