Re: Memory again

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> `garbage-collect' is supposed to give that info.  At least it does give
>> info about the data that's kept under alloc.c's control because
>> of fragmentation (these are counted as "free cells").
> I would like to propose a function which explicitly says how much free memory
> the Emacs process holds.

For the part that alloc.c holds, the "memory-usage" package in ELPA
should do the trick (or can be improved to do it).

> It's especially useful when there is a way to ask system malloc about
> how much free memory is in the heap.

It'd be great to add this data when available, indeed.  Patch welcome.

> This may be helpful to distinguish real heap fragmentation from memory
> leaks and other misuses - if the sum of values returned by
> 'memory-free' is, say, 10% of heap size, then the real fragmentation
> enters into the game.

It may also be important to try and keep track of other allocations,
which are not under alloc.c's control (e.g. allocations performed by
GUI libraries).

>> I agree that we're probably going to see better overall results by
>> improving general memory use than by trying to attack
>> fragmentation problems.
> Among this list's subscribers, Nix <nix@[hidden]> is constantly
> reporting an enormous memory usage caused by Gnus.

I think we still have a leak there somewhere.


        Stefan