Re: [PATCH] IB/mlx5: Reduce mlx5_ib_wq cacheline bouncing

[Sagi Grimberg <sagig-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

>>> Anyway, I'm not sure about the alignment of the memory returned by
>>> kcalloc(), I should have known by the time but don't find time to
>>> figure how it's handled on various SL*B allocator implementation.
>>
>> Can you explain why should I worry about the alignment of kcalloc
>> here?
>
> Say it returns memory aligned on 16 bytes, then accessing some items in
> the array is going to touch 2 cachelines, defeating the purpose of the
> padding or the alignment attribute added to the item structure.

I see, I think the alignment is ARCH_KMALLOC_MINALIGN. I'm not aware
of aligned array allocation. Do you have a suggestion how can I align
the allocation? I can manually pad and align but it would mean I'd need
to save two extra pointers (aligned pointer and orig pointer for kfree)
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