On Fri, Apr 08, 2022 at 03:42:13PM +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. > > > > After this patch, ARCH_DMA_MINALIGN is expected to be used in static > > alignment annotations and defined by an architecture to be the maximum > > alignment for all supported configurations/SoCs in a single Image. > > ARCH_KMALLOC_MINALIGN, if different, is the minimum alignment guaranteed > > by kmalloc(). > > > > Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > --- > > include/linux/slab.h | 23 ++++++++++++++++++----- > > 1 file changed, 18 insertions(+), 5 deletions(-) > > > > diff --git a/include/linux/slab.h b/include/linux/slab.h > > index 373b3ef99f4e..d58211bdeceb 100644 > > --- a/include/linux/slab.h > > +++ b/include/linux/slab.h > > @@ -187,17 +187,30 @@ bool kmem_valid_obj(void *object); > > void kmem_dump_obj(void *object); > > #endif > > > > +/* > > + * slob does not support independent control of ARCH_KMALLOC_MINALIGN and > > + * ARCH_DMA_MINALIGN. > > + */ > > +#ifdef CONFIG_SLOB > > +#undef ARCH_KMALLOC_MINALIGN > > +#endif > Sorry for the noise. Yeah, the code above is making ARCH_KMALLOC_MINALIGN = ARCH_DMA_MINALIGN. I was confused :( > I think you should replace ARCH_KMALLOC_MINALIGN with ARCH_DMA_MINALIGN > in mm/slob.c too? Or detect minimum kmalloc alignment in runtime like SLAB/SLUB? > > current code seem to break with SLOB on machines that has 128 byte cache lines > because ARCH_KMALLOC_MINALIGN is 64? > > > + > > /* > > * Some archs want to perform DMA into kmalloc caches and need a guaranteed > > * alignment larger than the alignment of a 64-bit integer. > > - * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that. > > + * Setting ARCH_DMA_MINALIGN in arch headers allows that. > > */ > > -#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8 > > +#ifndef ARCH_DMA_MINALIGN > > +#define ARCH_DMA_MINALIGN __alignof__(unsigned long long) > > +#elif ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN) > > #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN > > -#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN > > -#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN) > > -#else > > +#endif > > + > > +#ifndef ARCH_KMALLOC_MINALIGN > > #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) > > +#else > > +#define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN > > +#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE) > > #endif > > > > /* > > > > -- > Thanks, > Hyeonggon -- Thanks, Hyeonggon
