On Tue, May 11, 2010 at 09:42:03AM +0300, Pekka Enberg wrote: > Hi Dmitry, > > On Tue, May 11, 2010 at 9:33 AM, Dmitry Torokhov > <dmitry.torokhov@xxxxxxxxx> wrote: > >> what guarantee exactly do you have for that statement ? > > > > The data is kmalloced, kmalloc aligns on cacheline boundary AFAIK which > > means that next kmalloc data chunk will not share "our" cacheline. > > No, there are no such guarantees. kmalloc() aligns on > ARCH_KMALLOC_MINALIGN or ARCH_SLAB_MINALIGN depending on which is > bigger but beyond that, there are no guarantees. You can, of course, > use kmem_cache_create() with SLAB_HWCACHE_ALIGN to align on cacheline > boundary. > The architectures that we are trying to deal with here should be forcing kmalloc to the cache boundary already though - otherwise they would not be able to used kmalloced memory for DMA buffers at all. Or am I utterly lost here? -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
