[petsc-dev] memory leaks in BCGSL when using KSPReset()

[Lisandro Dalcin]

On 12 April 2011 10:26, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
> On Apr 11, 2011, at 10:02 PM, Lisandro Dalcin wrote:
>
>> After adding this test in petsc4py-dev/test/test_ksp.py :
>>
>>    def testResetAndSolve(self):
>>        self.ksp.reset()
>>        self.testSolve()
>>        self.ksp.reset()
>>        self.testSolve()
>>        self.ksp.reset()
>>
>> it seems there is some memory bleeding:
>>
>> [0]Total space allocated 256 bytes
>> [ 0]80 bytes KSPSetUp_BCGSL() line 476 in
>> /home/devel/petsc/dev/src/ksp/ksp/impls/bcgsl/bcgsl.c
>>      [0]  KSPSetUp() line 184 in
>> /home/devel/petsc/dev/src/ksp/ksp/interface/itfunc.c
>>      [0]  KSPSolve() line 332 in
>> /home/devel/petsc/dev/src/ksp/ksp/interface/itfunc.c
>>
>> These are workspace arrays that are re-allocated at every KSPSetup_BCGSL call.
>>
>> Not sure about the proper way to fix this, but I would deallocate the
>> arrays at KSPReset_BCGSL. Can anyone help me with this?
>>
>    This could be a problem in many places: for example if eigenvalue computing is done with CG then I think those arrays will be reallocated.
>

Indeed. I'm not testing eigenvalue computing. I could try to add the
options to my testsuite and see what happens.

>   Previously I guess KSPSetUp_XXX() never had a reason to be called more than once, with reset now it is. So that means that all arrays allocated in KSPSetUp_XXX() should be freed in KSPReset_XXX()? If this is correct then it is easily fixed by moving them from KSPDestroy_XXX().
>

Well, In my latest push I was lazy enough as to not remove the
PetscFree() call to Reset_XXX. After all, PetscFree() nullifies the
pointer, so we are safe. If you want me to fix this, let me know.

PS: Could any of you check BCGLS for a few "ksp->setupstage =
KSP_SETUP_NEW;" lines? That really smells, such hack forces a full
(not just in the subype)
KSPSetup() in the next KSPSolve().

-- 
Lisandro Dalcin
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