custom memory management

[Wiktor Zychla [C# MVP]]

suppose I implement a custom caching mechanism for my custom ORM
implementation. suppose I'd like the client code to be able to define the
maximum amount of memory the cache is allowed to occupy.

however, I have no idea how from within the code I can even retrieve the
amount of memory an object takes. the System.GC.GetTotalMemory method seem
to retrieve the total amount of allocated memory while I would be interested
in monitoring the memory usage for a selected object.

what I need is just a right direction of research.

Thanks in advance
Wiktor Zychla

 

[Nicholas Paldino [.NET/C# MVP]]

Wiktor,

The two ways I could think of doing this would be to hook into the
debugging interface in the CLR, or to provide a custom host which would be
able to report the memory consumed by your particular object(s).

The thing is though, why the need for this kind of mechanism? It's
surely more trouble than it's worth, and there is usually not a justifiable
need (not saying yours isn't, but it would help to know why, given that you
have GC to take care of memory management issues for you).

 

[Ben Voigt [C++ MVP]]

suppose I implement a custom caching mechanism for my custom ORM
implementation. suppose I'd like the client code to be able to define the
maximum amount of memory the cache is allowed to occupy.

however, I have no idea how from within the code I can even retrieve the
amount of memory an object takes. the System.GC.GetTotalMemory method seem
to retrieve the total amount of allocated memory while I would be
interested in monitoring the memory usage for a selected object.

First you must define the boundary of your object. Is it:

(A) the memory block on the heap which the reference points to
(B) the set of all blocks reachable from that object (i.e. consider the
object as a GC root)
(C) the set of all blocks which could be freed if the object was eliminated
from the cache
(D) something else