Re: [PATCH] slab: fix slab flags for archs use alignment larger 64-bit

From: Giuseppe CAVALLARO
Date: Fri Feb 13 2009 - 05:16:17 EST


Pekka Enberg wrote:
> Hi Giuseppe,
>
> On Fri, Feb 13, 2009 at 12:46 PM, Giuseppe CAVALLARO
> <peppe.cavallaro@xxxxxx> wrote:
>
>> 1) LOG with my patch:
>> root@linux:~# cat /proc/meminfo | grep Slab
>> Slab: 2612 kB
>>
>> 2) LOG without my patch:
>> root@linux:~# cat /proc/meminfo | grep Slab
>> Slab: 2504 kB
>>
>
> That's not too bad. I assume it's L1_CACHE_BYTES set to 32 bytes?
you are perfectly right.
> One big problem with your patch is that on some MIPS configurations
> ARCH_KMALLOC_MINALIGN is as big as 128.
Agree again and problem understood... thanks!
> So if you're going to do this, you can't use ARCH_KMALLOC_MINALIGN directly but add a some
> SLAB_MAX_DEBUG_ALIGN which can be overridden by architecture code.
>
If you like, I can prepare a patch in any case.
Then we can decide if it actually adds complexity and discard it.
Otherwise we could maintain it.
> One obvious question, though, is whether all this is worth the added
> complexity. I mean, we've managed "just fine" without it for years.
> Paul, thoughts?
>
> Pekka
>
>

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