Subject: Re: Partial fix for the NetBSD VM problem
To: Greg Hudson <email@example.com>
From: Phil Knaack <firstname.lastname@example.org>
Date: 03/04/1996 14:16:21
>After this patch, the following problems will remain:
> * If you modify a file through the filesystem, the changes
> will not necessarily affect mmap()'d regions until an
> * If you modify an mmap()'d region with MAP_SHARE, the changes
> will not necessarily affect the filesystem until an msync()
> or munmap().
> [ vm_mmap.c patch ]
Just at a cursory glance, and with the understanding that I don't
know a heck of a lot about what POSIX.1 says, it seems to me that the second
point is one which seems more than reasonable, and not a bug.
By the same token, the first one seems almost *correct* to me.
Perhaps I'm thinking in a different paradigm, but it seems to me
to be dangerous to "assume" that these two problems do not exist in any
given system a package you're designing may be run on.
It just seems to me as a design _flaw_ for a design solution to
use _both_ read/write and mmap on the same file. Sort of a lack of
purity of design thing.
My 2 pfennig.
Phillip F Knaack email@example.com
Database Programmer, NCREMP Student Development Group
ISU Extension Project Vincent, Iowa State University