Re: writable swap cache explained (it's weird)

[Richard Gooch <Richard.Gooch@atnf.CSIRO.AU>]

Linus Torvalds writes:
> 
> 
> On Thu, 30 Jul 1998, Benjamin C.R. LaHaise wrote:
> > 
> > (a) sounds like the Obvious Thing To Do in the mmap method for /proc, but
> > will break xdos.  Wtf were they thinking in writing that insane code?
> > Hmmm, this bug probably applies to 2.0 too....  in a much more subtle
> > fashion.
> 
> The insane code is indeed insane, but I think I understand why they did
> it: they didn't want to mess around with sysv shared memory regions.
> 
> I'd love to just completely get rid of mmap() on /proc/self/mem, because
> it actually is a bad idea completely (not just the shared mappings - even
> a private mapping of another mapping that is shared has simply completely
> untenable logical problems). 
> 
> I'd much more prefer for somebody to take the time to change dosemu to use
> the standard (and supported) sysv shared memory setup than to make any
> kernel changes.. 

I think it would be better if they used the new POSIX.4 SHM support
(shm_open(3) and friends). To do that, though, the shmfs patch would
need to be included in the kernel, though. Yeah, yeah, I know: feature
freeze. But when has that ever stopped you? ;-)

				Regards,

					Richard....
--
This is a majordomo managed list.  To unsubscribe, send a message with
the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org