Re: Latest changes in redisplay code

[Eli Zaretskii]

> Date: Wed, 06 Feb 2013 11:37:30 +0400
> From: Dmitry Antipov <address@hidden>
> CC: address@hidden
> 
> On 02/05/2013 10:01 PM, Eli Zaretskii wrote:
> 
> > In any case, the potential for problems is still there, because now
> > w->base_line_pos gets reset to zero in many more places than it was
> > before.  Previously, only xdisp.c would manipulate this attribute in a
> > few well-defined places.  Now it can be reset by any function that
> > calls adjust_window_count, including wset_buffer, which is called from
> > many primitives, most of them outside xdisp.c.  Therefore, it's quite
> > possible that we will now have to count from the beginning of the
> > buffer much more frequently than we did before.  In large buffers,
> > this could be quite a hit.
> 
> Hm. I'll try to reproduce such a situation and check what happens.
> Maybe we should invalidate window_end_valid and base_line_pos only
> if either window is really switched to another buffer or buffer
> is changed.

That'd be hard, because there are many places that switch to another
buffer temporarily, and they all call adjust_window_count.