Re: [Help-smalltalk] Strategy to finding memleaks

[Paolo Bonzini]

On 04/09/2011 09:55 AM, Holger Hans Peter Freyther wrote:
> Hi Paolo,
>
> my postgres code is now working like it should and to test it I was letting it
> run in a loop and I see that there is an increase in usage of memory. My first
> try was to use ObjectMemory to force a global garbage collect but that did not
> change anything, I will try with compacting heaps now as well.
>
> Do you have any strategy to find memory leaks? How is this Eden working? If an
> Object is moved there it will never be GCed?

No, absolutely not!  Objects are always GCed.  Eden is where objects are 
_born_, and until they are in the eden reclaiming them is particularly 
efficient.

To find memory leaks, I suggest you use instanceCount and find objects 
with a very large number of instances.  From there, finding the owners 
(which may not have a very large number of instances, but are the roots 
of the leak) is usually easy.  Possibly you can do something like

    x := SomeClass someInstance.
    [o := x allOwners. o isEmpty] whileTrue: [ x := x nextInstance ].
    (o collect: [ :each |each class]) asBag

and recurse on the classes shown in the bag.

Usually, saving the image and doing the above in the REPL will also be 
useful to find leaks.

I believe the archives have some information on finding leaks related to 
Iliad (July 2009, should be).

Paolo