Date:	Tue, 30 Aug 94 18:08:46 GMT
From:	dolan AT fnoc DOT navy DOT mil (Kent Dolan)
To:	dj AT ctron DOT com
Subject:	Re: bugs in exec.c et al
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu

DJ (an androgynous choice of monikers, indeed),

Hmmm,


BB>>> ..., except that DJ says it isn't supposed to work this way;
BB>>> _go32_dpmi_remaining_physical_memory() is supposed to track
BB>>> allocations.
 
KPD>> Huh?  If the allocation only effectively allocates virtual memory, then
KPD>> a function named ...remaining_physical_memory should ignore anything
KPD>> that is not yet occupying physical memory.  Anything else would disobey
KPD>> the principle of least astonishment.

DJ> Now *I* am confused.  The original intent of this function was to see
DJ> how much space one could alloc before swapping happened.  What's the
DJ> best definition for this after swapping everything out for a spawn?
DJ> What *should* it mean?

I'd prefer that it mean what it says.  If you're calling this during a
spawn, then it's the spawned job that is doing the calling, and it wants
to know how much physical memory is available to _it_, _right_ _now_.

If you're calling this _after_ a spawn, while most of the current task is
in virtual memory waiting until it is needed to be swapped back in, then
again you the programmer are interested in how much physical memory is
available _right_ _now_, because you might have some i/o bound subtask that
would run much better in memory, if it and its data would all fit in memory
_right_ _now_, and in that case, you don't really much care about the bunch
of code sitting swapped out to disk, unless it is going to be involved in
the current subtask.

My opinions only, I have several decades of programming expreience, but that
doesn't make me a universal expert.  Nor anything close.

Xanthian.
--
Kent, the man from xanth.
Kent Paul Dolan, CSC contractor at Fleet Numerical.  (408) 656-4363.
(Navy Unix email:   )  (Navy cc:Mail email: )  (real world email:     )
<dolan AT fnoc DOT navy DOT mil>  <dolank AT fnoc DOT navy DOT mil>  <xanthian AT well DOT sf DOT ca DOT us>

- Raw text -