D's New GC and Object Allocation Pools

[Mike via Digitalmars-d]

On Sunday, 26 October 2014 at 03:37:47 UTC, Maxime 
Chevalier-Boisvert wrote:
>
> I also wanted to ask if there was an implementation of an 
> object pool in the standard library. If not, I'm wondering what 
> the best way to implement this is. Is there any way to overload 
> new and destroy?

I'm not an authority on the subject, but I believe all you need 
to do is provide alternate implementations for _d_newclass[1] and 
destroy[2].  I experimented with this a little bit about a year 
ago, and it worked well for me.  I modified druntime for my 
experiments, but there may be a way to link in your 
implementations instead of the defaults at link time, thus giving 
you an "override" effect.

>
> I was thinking of using the templated emplace operator from 
> std.conv to allocate class objects into a large flat array, and 
> to derive pool-allocated classes from a PoolObject base class. 
> This base class would contain linked list pointers to implement 
> a free list, as well as templated static methods to allocate 
> and free the objects. Any advice welcome.

If you haven't already, check out the Memory Management article 
on the D Wiki [3].  It's a nice article that was written some 
time ago by an unknown author and migrated to the wiki last year 
to help keep it maintained.  I particularly like Explicit Class 
Allocation[4], Mark/Release[5], and Free Lists[6] as alternatives.

Mike

[1] - 
https://github.com/D-Programming-Language/druntime/blob/master/src/rt/lifetime.d#L60
[2] - 
https://github.com/D-Programming-Language/druntime/blob/master/src/object_.d#L2379
[3] - http://wiki.dlang.org/Memory_Management
[4] - 
http://wiki.dlang.org/Memory_Management#Explicit_Class_Instance_Allocation
[5] - http://wiki.dlang.org/Memory_Management#Mark.2FRelease
[6] - http://wiki.dlang.org/Memory_Management#Free_Lists