To: linux-kernel@vger.kernel.org
From: mru@kth.se (=?iso-8859-1?q?M=E5ns_Rullg=E5rd?=)
Subject: Re: [BUG] alignment problem in net/core/flow.c:flow_key_compare
Date: Thu, 18 Mar 2004 12:25:57 +0100
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mru@kth.se (M?ns Rullg?rd) writes:

> There is a problem with alignment in the flow_key_compare function in
> net/core/flow.c.  It takes arguments of type struct flowi * and casts
> them to flow_compare_t *, which is 64 bits on 64-bit machines.  It
> then proceeds to read and compare 64-bit values from these pointers.
> The problem is that struct flowi only requires 32-bit alignment, so
> these reads cause numerous unaligned exceptions.  On average, I get
> nearly 1000 unaligned exceptions per second.
>
> The solutions I see are either to force the alignment of struct flowi
> to 64 bits, or to use 32-bit access in flow_key_compare.

I forgot to mention that this is kernel 2.6.4.

-- 
M?ns Rullg?rd
mru@kth.se

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