www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - Hot to destroy a big Array and free RAM

reply Giovanni Di Maria <calimero22 yahoo.it> writes:
How to delete an array and to free RAM

Hi. Can you help me please?
I have tried many experiments but without success.
I have a big array of arrays (matrix[][]).

After to have filled of data i measure the RAM with an utility 
(for example Wise Memory Optimizer).

Then i try to destroy the array in many modes, but the free RAM 
is still the same.

Can you help me please?
Thank you very much
Giovanni Di Maria
Dec 12 2018
parent reply Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:
On Wednesday, December 12, 2018 1:14:47 AM MST Giovanni Di Maria via 
Digitalmars-d wrote:

 How to delete an array and to free RAM

 Hi. Can you help me please?
 I have tried many experiments but without success.
 I have a big array of arrays (matrix[][]).

 After to have filled of data i measure the RAM with an utility
 (for example Wise Memory Optimizer).

 Then i try to destroy the array in many modes, but the free RAM
 is still the same.


As I understand it. under normal circumstances, the GC never returns memory
to the OS. Even if it's collected during a GC cycle, it keeps it around so
that it can be reused when the GC needs to allocate memory again. That being
said, looking at the documentation for core.memory, it looks like
GC.minimize might return unused memory to the OS if it's called:

https://dlang.org/phobos/core_memory.html#.GC.minimize

Regardless, you'll need to make sure that there are no references remaining
to any portion of that memory in your program, or the GC won't even collect
it. The program must no longer have access to any portion of the allocated
block for the GC to be able to safely collect it.

Worst case, if you need more control over how the memory is returned to the
OS, then you may need to use malloc/free or one of the allocators from
std.experimental.allocator rather than using the GC.

BTW, questions like this belong in D.Learn. This newsgroup/forum/list is for
general D discussions, not for questions related to learning how to use D.

- Jonathan M Davis
Dec 12 2018
next sibling parent Giovanni Di Maria <calimero22 yahoo.it> writes:
Hi Jonathan M Davis.
Thank you very very much.
Excuse me for the wrong forum.
Regards.
Ciao
Giovanni
Dec 12 2018
prev sibling parent Giovanni Di Maria <calimero22 yahoo.it> writes:
On Wednesday, 12 December 2018 at 08:34:25 UTC, Jonathan M Davis 
wrote:

 On Wednesday, December 12, 2018 1:14:47 AM MST Giovanni Di 
 Maria via Digitalmars-d wrote:

 [...]


 As I understand it. under normal circumstances, the GC never 
 returns memory to the OS. Even if it's collected during a GC 
 cycle, it keeps it around so that it can be reused when the GC 
 needs to allocate memory again. That being said, looking at the 
 documentation for core.memory, it looks like GC.minimize might 
 return unused memory to the OS if it's called:

 [...]





Hi Jonathan M Davis.
Thank you very very much.
Excuse me for the wrong forum.
Regards.
Ciao
Giovanni
Dec 13 2018