Re: [PATCH 01/10] mm/slab: Decouple ARCH_KMALLOC_MINALIGN from ARCH_DMA_MINALIGN

Catalin Marinas
2022-04-06T08:53:33Z

On Wed, Apr 06, 2022 at 08:59:18AM +0900, Hyeonggon Yoo wrote:
> On Tue, Apr 05, 2022 at 02:57:49PM +0100, Catalin Marinas wrote:
> > In preparation for supporting a dynamic kmalloc() minimum alignment,
> > allow architectures to define ARCH_KMALLOC_MINALIGN independently of
> > ARCH_DMA_MINALIGN. In addition, always define ARCH_DMA_MINALIGN even if
> > an architecture does not override it.
>
> [ +Cc slab maintainer/reviewers ]
>
> I get why you want to set minimum alignment of kmalloc() dynamically.
> That's because cache line size can be different and we cannot statically
> know that, right?
>
> But I don't get why you are trying to decouple ARCH_KMALLOC_MINALIGN
> from ARCH_DMA_MINALIGN. kmalloc'ed buffer is always supposed to be DMA-safe.

Arnd already replied. With this series, kmalloc'ed buffers are still
DMA-safe for the SoC the kernel is running on.

--
Catalin