Subject: bug#56682: Fix the long lines font locking related slowdowns

From: Dmitry Gutov <[email-masked]>
Date: Fri, 5 Aug 2022 15:21:24 +0300

On 05.08.2022 15:16, Gregory Heytings wrote:
> 
>>> If and when it is solved, we could revisit this issue.
>>
>> The locked narrowing currently in effect makes it impossible to 
>> investigate this problem or improve the behavior :-(
>>
> 
> How so?  It is fully backward compatible, just (setq long-line-threshold 
> nil).  If what you want is only to remove the locked narrowing, comment 
> out the relevant line in xdisp.c.

That brings back the performance problems in redisplay, which have a 
more pronounced effect, overshadowing both issues and potential 
improvements in font-lock.