On Wed, May 14, 2014 at 2:10 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > I've just spent two days looking at stuff that uses time_t inside > of the kernel, to get a better idea of what we actually need to > do to get provide new user interfaces for the existing architectures. > > My impression so far is that we're better off fixing it for the > existing architectures first and then using the new interfaces > exclusively on new ones, rather than changing over the ABI for > all new architectures at this point, which would likely create > yet another variant to maintain in the long run. > > Using 64-bit time_t on x32 is fine, because it's fast to operate > in user space with 64-bit registers, and the kernel is 64-bit > anyway. Inside of the kernel, we may get into trouble using > a 64-bit time_t on 32-bit architectures because of the overhead > in 64-bit math, e.g. all the timekeeping code that is based on > timespec or some code paths in file systems and network code where > we actually require division of time_t values. > We clearly have to change that code in some for to deal with y2038, > but 64-bit time_t may not be the best option. A lot of the > in-kernel code can probably use ktime_t, which we can change > to a different representation (e.g. 34 bit seconds) if needed, > and all the code that is only interested in relative time > (e.g. nanosleep) doesn't have to change at all. Hi Arnd, >From your comment above, can I assume we don't need this patchset any more? Regards Ley Foon -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
