On Tue, Jan 17, 2012 at 10:45 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > On 01/16, Will Drewry wrote: >> >> On Mon, Jan 16, 2012 at 12:37 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: >> > >> > Yes, thanks, I forgot about compat tasks again. But this is easy, just >> > we need regs_64_to_32(). >> >> Yup - we could make the assumption that is_compat_task is always >> 32-bit and the pt_regs is always 64-bit, then copy_and_truncate with >> regs_64_to_32. Seems kinda wonky though :/ > > much simpler/faster than what regset does to create the artificial > user_regs_struct32. True, I could collapse pt_regs to looks like the exported ABI pt_regs. Then only compat processes would get the copy overhead. That could be tidy and not break ABI. It would mean that I have to assume that if unsigned long == 64-bit and is_compat_task(), then the task is 32-bit. Do you think if we ever add a crazy 128-bit "supercomputer" arch that we will add a is_compat64_task() so that I could properly collapse? :) I like this idea! >> > Doesn't matter. I think Indan has a better suggestion. >> >> I disagree, but perhaps I'm not fully understanding! > > I have much more chances to be wrong ;) I leave it to you and Indan. We're being very verbose. I hope we can come to a good place! I took a break from my response to reply here :) thanks! will -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
