Subject: Re: kernel map entry merging and PR 24039
To: None <>
From: YAMAMOTO Takashi <>
List: tech-kern
Date: 12/02/2004 23:26:43

> >can you explain what's an important difference?  thanks.
> using up memory is simply not the same as reserving it.  reserved
> memory can be used for something at a later point in time.  used
> memory cannot.

memory used for map entries can be used for something else
when it's no longer needed (ie. after the map is unmapped.)

> imho, using 2000 instead of 200 (or even 20) map entries cannot be
> considered a reaonable solution to any problem.  unless the problem is
> that you have too much ram.  :)

if you have only 20 entries and haven't seen the deadlock problem,
it just means you're lucky enough.
i don't think it's reasonable to rely on the pure luck at all.

and of course, regardless of what pmap(1) shows, you always have
>=1000 reserved entries.