On 04/30, Sudeep Holla wrote: > > On Mon, Mar 18, 2019 at 04:33:22PM +0100, Oleg Nesterov wrote: > > > > And it seems that _TIF_WORK_SYSCALL_ENTRY needs some cleanups too... We > > don't need > > "& _TIF_WORK_SYSCALL_ENTRY" in syscall_trace_enter, and > > _TIF_WORK_SYSCALL_ENTRY > > should not include _TIF_NOHZ? > > > > I was about to post the updated version and checked this to make sure I have > covered everything or not. I had missed the above comment. All architectures > have _TIF_NOHZ in their mask that they check to do work. And from x86, I read > "...syscall_trace_enter(). Also includes TIF_NOHZ for enter_from_user_mode()" > So I don't understand why _TIF_NOHZ needs to be dropped.
I have already forgot this discussion... But after I glanced at this code again I still think the same, and I don't understand why do you disagree. > Also if we need to drop, we can address that separately examining all archs. Sure, and I was only talking about x86. We can keep TIF_NOHZ and even set_tsk_thread_flag(TIF_NOHZ) in context_tracking_cpu_set() if some arch needs this but remove TIF_NOHZ from TIF_WORK_SYSCALL_ENTRY in arch/x86/include/asm/thread_info.h, afaics this shouldn't make any difference. And I see no reason why x86 needs to use TIF_WORK_SYSCALL_ENTRY in syscall_trace_enter(). Oleg.
