Re: [PATCHv4 10/12] notes.c: Implement simple memory pooling of leaf nodes

[Johan Herland <johan@herland.net>]

On Thursday 27 August 2009, Johan Herland wrote:
> On Thursday 27 August 2009, Alex Riesen wrote:
> > On Thu, Aug 27, 2009 at 03:43, Johan Herland<johan@herland.net> wrote:
> > > When allocating a new memory pool, the older pool is leaked, but this
> > > is no worse than the current situation, where (pretty much) all
> > > leaf_nodes are leaked anyway.
> >
> > Could you return the unused nodes back into the mempool?
> > By making the pool a preallocated list, perhaps?
>
> Yes, maintaining a free-list is certainly possible. However, the number
> of free()d leaf_nodes is relatively small (only subtree entries are
> free()d after unpacking them into the tree structure), so I'm not sure it
> pays off, runtime-wise.

I played around with the free-list idea, but it cost more than the memory 
pooling code saved in the first place. I'm leaning towards dropping the 
whole memory pooling idea, as the small run-time improvement is probably not 
worth the added complexity. We'll see. I'll re-evaluate once I've refactored 
the code according to the other threads of this discussion.

> > And then it is trivial to provide a deallocation function for the
> > mempool, which something really concerned about the memleak can call
> > (like when or if libgit get more usable in an application context).
>
> Yes, I plan to provide a free_notes() function that free()s all the
> memory associated with the notes data structure. This would of course
> keep references to all the mempools, and deallocate them (along with all
> the int_nodes).

This still stands, of course. Should be part of the next iteration.


...Johan

-- 
Johan Herland, <johan@herland.net>
www.herland.net