Date: Tue, 20 Apr 2004 11:25:56 -0700
From: Andrew Morton <akpm@osdl.org>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: andrea@suse.de, agruen@suse.de, linux-kernel@vger.kernel.org
Subject: Re: slab-alignment-rework.patch in -mc
Message-Id: <20040420112556.400ea49e.akpm@osdl.org>
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Manfred Spraul <manfred@colorfullife.com> wrote:
>
> Andrea Arcangeli wrote:
> 
> >On Tue, Apr 20, 2004 at 12:24:23AM -0700, Andrew Morton wrote:
> >  
> >
> >>So I do think that we should either make "align=0" translate to "pack them
> >>densely" or do the big sweep across all kmem_cache_create() callsites.
> >>    
> >>
> >
> >agreed.
> >  
> >
> What about this proposal:
> SLAB_HWCACHE_ALIGN clear: align to max(sizeof(void*), align).
> SLAB_HWCACHE_ALIGN set: align to max(cpu_align(), align).
> 
> cpu_align is the cpu cache line size - either runtime or compile time.
> 
> Or are there users that want an alignment smaller than sizeof(void*)?

I doubt if this is likely to cause problems, and in cases where we expect
to have really large numbers of objects we could explicitly select an
alignment of 4 anyway.

But why would you choose to make the "SLAB_HWCACHE_ALIGN clear" case use
sizeof(void*) rather than sizeof(int)?
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