On Fri, Oct 16 2020 at 12:54, Oleg Nesterov wrote:
> On 10/16, Thomas Gleixner wrote:
>
> But again, I won't argue. And to remind, we do not really need to touch
> arch_do_signal() at all. We can just add
>
> if (test_thread_flag(TIF_NOTIFY_SIGNAL))
> tracehook_notify_signal();
>
> if (!task_sigpending(current))
> return 0;
>
> at the start of get_signal() and avoid the code duplication automatically.
That works as well and is smart, but it's completely non obvious while
if (ti_work & _TIF_NOTIFY_SIGNAL)
tracehook_notify_signal();
arch_do_signal_or_restart(ti_work & _TIF_SIGPENDING);
makes it entirely clear to follow the logic and it just operates on
cached ti_work.
You can still do this for the non generic entry architectures:
if (!IS_ENABLED(CONFIG_GENERIC_ENTRY) &&
(test_thread_flag(TIF_NOTIFY_SIGNAL))
tracehook_notify_signal();
to avoid the churn in arch/*.
Thanks,
tglx
