On 04/17/2013 02:55 AM, zhang.yi20@xxxxxxxxxx wrote: > Darren Hart <dvhart@xxxxxxxxxxxxxxx> wrote on 2013/04/17 01:57:10: > >> Again, a functional testcase in futextest would be a good idea. This >> helps validate the patch and also can be used to identify regressions in >> the future. > > I will post the testcase code later. > >> >> What is the max value of comp_idx? Are we at risk of truncating it? >> Looks like not really from my initial look. >> >> This also needs a comment in futex.h describing the usage of the offset >> field in union futex_key as well as above get_futex_key describing the >> key for shared mappings. >> >> > > As far as I know , the max size of one hugepage is 1 GBytes for x86 cpu. > Can some other cpus support greater hugepage even more than 4 GBytes? If > so, we can change the type of 'offset' from int to long to avoid > truncating. I discussed this with Dave Hansen, on CC, and he thought we needed 9 bits, so even on x86 32b we should be covered. -- Darren Hart Intel Open Source Technology Center Yocto Project - Technical Lead - Linux Kernel -- 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>