> On May 26, 2016, at 12:30 PM, Bart Van Assche <bart.vanassche@xxxxxxxxxxx> wrote: > > On 05/26/2016 09:24 AM, Yishai Hadas wrote: >> On 5/25/2016 6:58 PM, Chuck Lever wrote: >>> When debugging is disabled, kzalloc returns page-aligned >>> addresses: >> >> Is it defined some where that regular kzalloc/kmalloc guaranties to >> return a page-aligned address as you see in your testing ? if so the >> debug mode should behave the same. Otherwise we can consider using any >> flag allocation that can force that if such exists. >> Let's get other people's input here. > > My understanding is that the fact that k[mz]alloc() returns a page-aligned buffer if the allocation size is > PAGE_SIZE / 2 is a side effect of the implementation and not something callers of that function should rely on. I think the only assumption k[mz]alloc() callers should rely on is that the allocated memory respects ARCH_KMALLOC_MINALIGN. I agree. mlx4_alloc_priv_pages() is carefully designed to correct the alignment of the buffer, so it already assumes that it is not getting a page-aligned buffer. The alignment isn't the problem here, though. It's that the buffer contains a page-boundary. That is guaranteed to be the case for HCAs that support more than 512 sges, so that will have to be addressed (at least in mlx5). -- Chuck Lever -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
