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Re: diskfs_catch_exception
From: |
Marcus Brinkmann |
Subject: |
Re: diskfs_catch_exception |
Date: |
Mon, 9 Dec 2002 21:42:06 +0100 |
User-agent: |
Mutt/1.4i |
On Mon, Dec 09, 2002 at 03:38:40PM -0500, Neal H. Walfield wrote:
> > File system pagers are never mapped into the filesystem address space. The
> > filesystem pagers exist solely for user mappings, and for read/write
> > operations via pager_memcpy (see libdiskfs/rdwr-internal.c). As there is no
> > mapping, there is no need to protect against signals when accessing
> > them.
>
> _diskfs_rdwr_internal creates mappings (via pager_memcpy) of file
> pagers. It also use a preemptor.
Ah, ok, that's interesting. However, from the perspective Marco was taking,
this is only an implementation detail. If the server could install the
mapping directly into the user's task, that would probably be better for
performance (is that how it will be done in L4?), and it would be all the
same for Marco's understanding of diskfs_catch_exception.
Thanks,
Marcus
--
`Rhubarb is no Egyptian god.' GNU http://www.gnu.org marcus@gnu.org
Marcus Brinkmann The Hurd http://www.gnu.org/software/hurd/
Marcus.Brinkmann@ruhr-uni-bochum.de
http://www.marcus-brinkmann.de/