Re: [PATCH for v3.18] mm/slab: fix unalignment problem on Malta with EVA due to slab merge

[Christoph Lameter]

On Fri, 31 Oct 2014, Joonsoo Kim wrote:

> alloc_unbound_pwq() allocates slab object from pool_workqueue. This
> kmem_cache requires 256 bytes alignment, but, current merging code
> doesn't honor that, and merge it with kmalloc-256. kmalloc-256 requires
> only cacheline size alignment so that above failure occurs. However,
> in x86, kmalloc-256 is luckily aligned in 256 bytes, so the problem
> didn't happen on it.

That luck will run out when you enable debugging. But then that also
usually means disablign merging.

> To fix this problem, this patch introduces alignment mismatch check
> in find_mergeable(). This will fix the problem.

Acked-by: Christoph Lameter <cl@xxxxxxxxx>
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