Message-ID: <3F3D558D.5050803@colorfullife.com>
Date: Fri, 15 Aug 2003 23:50:05 +0200
From: Manfred Spraul <manfred@colorfullife.com>
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: linux-kernel@vger.kernel.org
Subject: Re: [BUG] slab debug vs. L1 alignement
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Ben wrote:

>Currently, when enabling slab debugging, we lose the property of
>having the objects aligned on a cache line size.
>  
>
Correct. Cache line alignment is advisory. Slab debugging is not the 
only case that violates the alignment, for example 32-byte allocations 
are not padded to the 128 byte cache line size of the Pentium 4 cpus. I 
really doubt we want that.

Have you looked at pci_pool_{create,alloc,free,destroy}? The functions 
were specifically written to provide aligned buffers for DMA operations. 
Perhaps SCSI should use them?

--
    Manfred

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