On Thu, Feb 19, 2015 at 05:33:59PM +0100, Vojtech Pavlik wrote: > On Thu, Feb 19, 2015 at 10:24:29AM -0600, Josh Poimboeuf wrote: > > > > No, these tasks will _never_ make syscalls. So you need to guarantee > > > they don't accidentally enter the kernel while you flip them. Something > > > like so should do. > > > > > > You set TIF_ENTER_WAIT on them, check they're still in userspace, flip > > > them then clear TIF_ENTER_WAIT. > > > > Ah, that's a good idea. But how do we check if they're in user space? > > I don't see the benefit in holding them in a loop - you can just as well > flip them from the syscall code as kGraft does.
But we were talking specifically about HPC tasks which never make syscalls. -- Josh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
