Ticket #620 (assigned defect)

Opened 1 year ago

Last modified 1 year ago

memory still reachable in vector_rational_dense_21Vector_rational_dense__init

Reported by: mabshoff Assigned to: mabshoff (accepted)
Priority: major Milestone: sage-3.4
Component: memleak Keywords:
Cc:

Description

This is caused when running Sage 2.8.3.6+malb's fix for #566: 

for i in range(3):
    get_memory_usage()
    m = ModularSymbols(501,2).decomposition(3); 
    del m; ModularSymbols_clear_cache(); 
    get_memory_usage()

and results in 

==8920== LEAK SUMMARY:
==8920==    definitely lost: 1,518,830 bytes in 183,739 blocks.
==8920==    indirectly lost: 288,408 bytes in 610 blocks.
==8920==      possibly lost: 489,439 bytes in 1,002 blocks.
==8920==    still reachable: 160,311,066 bytes in 872,845 blocks.
==8920==         suppressed: 0 bytes in 0 blocks.

The exact problem: 

==8920== 1,612,736 bytes in 446 blocks are still reachable in loss record 2,367 of 2,372
==8920==    at 0x4A05A66: malloc (vg_replace_malloc.c:207)
==8920==    by 0x210A2D65: __pyx_f_21vector_rational_dense_21Vector_rational_dense__init (vector_rational_dense.c:770)
==8920==    by 0x210A0DE7: __pyx_tp_new_21vector_rational_dense_Vector_rational_dense (vector_rational_dense.c:865)
==8920==    by 0x45A272: type_call (typeobject.c:422)
==8920==    by 0x4156A2: PyObject_Call (abstract.c:1860)
==8920==    by 0x480783: PyEval_EvalFrameEx (ceval.c:3775)
==8920==    by 0x4865EF: PyEval_EvalCodeEx (ceval.c:2831)
==8920==    by 0x4CFED0: function_call (funcobject.c:517)
==8920==    by 0x4156A2: PyObject_Call (abstract.c:1860)
==8920==    by 0x41BE0C: instancemethod_call (classobject.c:2497)
==8920==    by 0x4156A2: PyObject_Call (abstract.c:1860)
==8920==    by 0x480783: PyEval_EvalFrameEx (ceval.c:3775)

Cheers,

Michael

Change History

09/07/2007 09:59:28 AM changed by mabshoff

  • status changed from new to assigned.

11/03/2007 07:06:02 AM changed by mabshoff

  • milestone changed from sage-2.9.1 to sage-2.9.

It looks like the ModularSymbols?_clear_cache() does nothing: 

mabshoff@sage:~$ sage
----------------------------------------------------------------------
| SAGE Version 2.8.11, Release Date: 2007-11-02                      |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------

sage: for i in range(3):
....:         print "start: ", get_memory_usage()
....:     m = ModularSymbols(501,2).decomposition(3);
....:     del m;
....:     print "deleted m: ", get_memory_usage()
....:     ModularSymbols_clear_cache();
....:     print "cache cleaned: ", get_memory_usage()
....:
start:  329.03515625
deleted m:  379.66015625
cache cleaned:  379.66015625
start:  379.66015625
deleted m:  391.63671875
cache cleaned:  391.63671875
start:  391.63671875
deleted m:  401.21484375
cache cleaned:  401.21484375

I had a quick look at the code and we play with weak references there, so that might be the cause. Same applies to #621.

Cheers,

Michael

11/03/2007 08:05:11 AM changed by was

  • milestone changed from sage-2.9 to sage-2.8.12.