Re: PATCH 2.6.21-rc1 aoe: handle zero _count pages in bios

From: Sam Hopkins
Date: Fri Mar 02 2007 - 11:12:26 EST


> Well, given that bi_end_io() is called after the "io" has completed, I'm
> assuming that networking has completely finished with the memory by the
> time bi_end_io() gets called.
>
> I guess one can envisage situations where that might not happen, but they'd
> be terribly buggy ones, surely.

This is actually quite common when using broadcom chipsets that take a
long time to clean out the tx ring. We send a command skb out to
write some data, get the response some tens of ms later and the
command skb (with the pages) still sits in the tx ring. I've gone to
some lengths to limit the skb memory used in aoe to help with the
OOM/swap issue and this has given me headaches.

Sam

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