Re: [PATCH] ARCH_SLAB_MINALIGN for 2.6.10-rc3

From: Paul Mundt
Date: Sun Dec 05 2004 - 17:22:04 EST


Hi Manfred,

On Sun, Dec 05, 2004 at 10:30:46PM +0100, Manfred Spraul wrote:
> >--- orig/include/asm-sh64/uaccess.h
> >+++ mod/include/asm-sh64/uaccess.h
> >@@ -313,6 +313,12 @@
> > sh64 at the moment). */
> >#define ARCH_KMALLOC_MINALIGN 8
> >
> >+/*
> >+ * We want 8-byte alignment for the slab caches as well, otherwise we have
> >+ * the same BYTES_PER_WORD (sizeof(void *)) min align in
> >kmem_cache_create().
> >+ */
> >+#define ARCH_SLAB_MINALIGN 8
> >+
> >
> >
> Could you make that dependant on !CONFIG_DEBUG_SLAB? Setting align to a
> non-zero value disables some debug code.
>
align is only being set to ARCH_SLAB_MINALIGN in kmem_cache_create()
where it is otherwise being set to BYTES_PER_WORD as a default. Unless I
am missing something, that will always set it non-zero irregardless of
whether ARCH_SLAB_MINALIGN is set.

Are you suggesting that ARCH_SLAB_MINALIGN be set to 0 in the
CONFIG_DEBUG_SLAB case? In that case, the check should be in mm/slab.c
and not in the arch-specific code (as any other platform wishing to have
fixed slab min alignment would have to do the same checks).

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