On Tue, Oct 17, 2017 at 01:55:43PM +0200, Marek Szyprowski wrote: > If I remember correctly, kernel guarantees that each kmalloced buffer is > always at least aligned to the CPU cache line, so CPU cache can be > invalidated on the allocated buffer without corrupting anything else. Yes, from slab.h: /* * 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. */ #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN) #else #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) #endif Mips sets this for a few subarchitectures, but it seems like you need to set it for yours as well.
