On Wed 12-10-16 08:28:17, zijun_hu wrote: > On 2016/10/12 1:22, Michal Hocko wrote: > > On Tue 11-10-16 21:24:50, zijun_hu wrote: > >> From: zijun_hu <zijun_hu@xxxxxxx> > >> > >> the LSB of a chunk->map element is used for free/in-use flag of a area > >> and the other bits for offset, the sufficient and necessary condition of > >> this usage is that both size and alignment of a area must be even numbers > >> however, pcpu_alloc() doesn't force its @align parameter a even number > >> explicitly, so a odd @align maybe causes a series of errors, see below > >> example for concrete descriptions. > > > > Is or was there any user who would use a different than even (or power of 2) > > alighment? If not is this really worth handling? > > > > it seems only a power of 2 alignment except 1 can make sure it work very well, > that is a strict limit, maybe this more strict limit should be checked I fail to see how any other alignment would actually make any sense what so ever. Look, I am not a maintainer of this code but adding a new code to catch something that doesn't make any sense sounds dubious at best to me. I could understand this patch if you see a problem and want to prevent it from repeating bug doing these kind of changes just in case sounds like a bad idea. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>