Re: [PATCH v2] arch/sparc: support NR_CPUS = 4096

[David Miller]

From: jane.chu@xxxxxxxxxx
Date: Mon, 5 Jun 2017 20:03:28 -0700

> On sun4v sparc, it looks like kzalloc(64, GFP_KERNEL) ends up
> allocating from kmalloc_caches[6] - a 64-byte kmem-cache allocated
> by kmem_cache_init() with SLAB_HWCACHE_ALIGN flag set, so it's in
> l3-cache-line-size alignment, i.e. 64byte.  I printed out the
> 'mondo' pa and verified that.

Please check this, because that is an implementation detail.  We have
three SLAB allocators.

For example, if the user enables SLOB, I bet you don't get that
alignment.

The only thing we are universally guaranteed is ARCH_KMALLOC_MINALIGN.

Please implement this properly, rather than relying upon things like
the above.

Thank you.