Re: [Caml-list] Finding "lost" references to OCaml heap values

["Richard W.M. Jones" <rich@annexia.org>]

On Tue, Oct 06, 2015 at 04:53:11PM +0100, Richard W.M. Jones wrote:
> On Tue, Oct 06, 2015 at 01:57:52PM -0000, Maxime Ransan (BLOOMBERG/ 731 LEX) wrote:
> > Just a hint about why the destructor is not called is that when using caml_alloc_custom at  https://github.com/libguestfs/libguestfs/blob/master/v2v/xml-c.c#L139, you are setting the used parameter to 0.  
> > 
> > As mentioned in http://caml.inria.fr/pub/docs/manual-ocaml-4.00/manual033.html#toc150 you can increase the ratio. A quick check would be to use a (used = 1, max = 1).
> 
> I guess this probably doesn't have anything to do with this
> specific problem, since I'm calling the GC explicitly.
> 
> However you're certainly correct that we don't pay any attention to
> passing decent values for caml_alloc_custom used/max.

I was going to add here:

... because it's hard to choose good values!  What's a good 'used' for
a libguestfs handle that might consume 100 MB?  And what's a good
'max' (maybe total physical RAM)?

Also, suppose I choose a large used/max (1/1 for example), is there a
danger that the major GC will do too much work?  The manual is unclear
on whether a bad choice of used/max can cause negative effects.

Rich.

-- 
Richard Jones
Red Hat