On Mon, Sep 24, 2018 at 03:17:16PM +0000, Christopher Lameter wrote: > On Mon, 24 Sep 2018, Bart Van Assche wrote: > > > /* > > * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned > > * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN > > * aligned pointers. > > */ > > kmalloc alignment is only guaranteed to ARCH_KMALLOC_MINALIGN. That power > of 2 byte caches (without certain options) are aligned to the power of 2 > is due to the nature that these objects are stored in SLUB. Other > allocators may behave different and actually different debug options > result in different alignments. You cannot rely on that. > > ARCH_KMALLOC minalign shows the mininum alignment guarantees. If that is > not sufficient and you do not want to change the arch guarantees then you > can open you own slab cache with kmem_cache_create() where you can specify > different alignment requirements. Christopher, thank you for clarifying the point! Then looks it should be reasonable for XFS to switch to kmem_cache_create() for addressing this issue. Thanks, Ming
