Re: Crashes if running WordPerfect 5.1

[Stas Sergeev <stsp@aknet.ru>]

Hello.

Bart Oldeman wrote:
>> don't need IPC SHM, and pagemalloc perhaps doesn't really hurt?
> I think I would personnally like it best if there wasn't a pagealloc
> either, but just multiple fd's.
After all I changed my mind again and
think it is not a good idea any more.
By using the kernel's allocator, we assume
it suits whatever the DOS prog may expect,
in particular that the subsequent malloc()s
returns the higher addresses each. There
were the programs that used to crash when
the subsequent malloc() was returning the
address below the one of the previous malloc.
I was reading this:
http://www.uwsg.iu.edu/hypermail/linux/kernel/0406.2/0874.html
In particular the following makes me to worry:
---
  0xbfxxxxxx ... _end_ of all mmaps, new mmaps go below old ones
---
So it seems the kernel guys may break that
our assumption and we'll be screwed. I don't
think we have to propagate the DOS requirements
to the kernel and ask the folks to not do this.
They should not care about what DOS progs do.
Instead we have to wrap that functionality
ourselves and provide whatever DOS progs are
expecting from us.
That's what pagemalloc did. Perhaps dropping
it was a premature decision. To stay on a safe
side, I think we have to put it back.