Re: [patch] slab: always follow arch requested alignments

From: Pekka Enberg
Date: Wed Jul 26 2006 - 07:21:06 EST

Hi Heiko,

On 7/22/06, Heiko Carstens <heiko.carstens@xxxxxxxxxx> wrote:
Sorry, I should have mentioned it: on s390 (32 bit) we set
This is needed since our common I/O layer allocates data structures that need
to have an eight byte alignment. Now, if I turn on DEBUG_SLAB, nothing works
anymore, simply because the slab cache code ignores ARCH_KMALLOC_MINALIGN and
uses an BYTES_PER_WORD alignment instead, which it shouldn't:

This is the bit I missed, sorry. I thought that the s390 hardware
mandates 8 byte alignment, but it really doesn't. So you're absolutely
right, you don't need to set ARCH_SLAB_MINALIGN and the alignment
calculation in slab is indeed broken for both, architecture and caller
mandated alignments.

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