Changes between Version 14 and Version 60 of Ticket #12215


Ignore:
Timestamp:
01/20/12 06:27:23 (16 months ago)
Author:
SimonKing
Comment:

I have updated the second patch, which was about fixing segfaults anyway.

As I already stated: I find it weird that the problem is solved by incrementing the reference count of the domain and codomain of an action when the action is deallocated. But it works, i.e., the doctests that used to segfault with #12313 and the old version of the patches run fine with the new patch version.

I need an expert opinion, though, and the full test suite is also to be run.

Concerning memleaks, here is the example from the ticket description.

With #12313 and the patches from here: 

sage: import sage.structure.unique_representation
sage: len(sage.structure.unique_representation.UniqueRepresentation.__classcall__.cache)
135
sage: 
sage: for i in range(2,1000):
....:         ring = ZZ.quotient(ZZ(i))
....:     vectorspace = ring^2
....: 
sage: import gc
sage: gc.collect()
16641
sage: len(sage.structure.unique_representation.UniqueRepresentation.__classcall__.cache)
227

With #12313 only: 

sage: import sage.structure.unique_representation
sage: len(sage.structure.unique_representation.UniqueRepresentation.__classcall__.cache)
151
sage: 
sage: for i in range(2,1000):
....:         ring = ZZ.quotient(ZZ(i))
....:     vectorspace = ring^2
....: 
sage: import gc
sage: gc.collect()
3805
sage: len(sage.structure.unique_representation.UniqueRepresentation.__classcall__.cache)
5142

So, it is a clear progress, and IIRC the patches comprise tests against at least one memory leak that is fixed. Needs review!

Apply trac12215_weak_cached_function.patch trac12215_segfault_fixes.patch

Legend:

Unmodified
Added
Removed
Modified

  • Ticket #12215

    • Property Cc jdemeyer, mhansen, vbraun added

  • Ticket #12215 – Description

    v14 v60  
    1414Related tickets: 
    1515  * #11521 (needs review, introducing weak references for caching homsets), and 
    16   * #715 (using weak references for caching coerce maps).  
     16  * #715 (needs review, using weak references for caching coerce maps).  
    1717  * #5970 (the polynomial rings cache use strong references, which may now be a duplicate, as I introduce the weak cache in #715) 
    1818 
    … …  
    2020  * not everything in Python can be weakref'ed, for example ``None`` cannot. 
    2121  * some results that are expensive to compute should not just be cached by a weak reference. Perhaps there is place for a permanent cache, or maybe some minimal age before garbage collecting it. 
     22 
     23__Apply__ 
     24 
     25 * [attachment:trac12215_weak_cached_function.patch] 
     26 * [attachment:trac12215_segfault_fixes.patch]