bug#19776: 25.0.50; HTML rendering is very slow

[Eli Zaretskii]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: larsi@gnus.org,  dmantipov@yandex.ru,  stefan@marxist.se,
>   19776@debbugs.gnu.org,  rms@gnu.org,  monnier@iro.umontreal.ca
> Date: Mon, 25 Oct 2021 19:52:33 +0200
> 
> >> > Also, if we are stuck in pselect call with a long timeout, we won't
> >> > get around to calling maybe_quit or process_pending_signals, right?
> >> 
> >> pselect will return as soon as input is available.
> >
> > I mean without timerfd, and if there's no input.
> 
> A signal also interrupts pselect.

Yes, but my reading of wait_reading_process_output is that in that
case we loop right back and re-enter pselect.