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

From
Johan Herland <johan@herland.net>
Date
Aug 27, 2009, 22:43 UTC
Message-ID
<200908280043.44261.johan@herland.net>
In-Reply-To
<200908271149.11003.johan@herland.net>
On Thursday 27 August 2009, Johan Herland wrote:
Show 13 quoted lines
> 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.

Show 8 quoted lines
> > 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
Previous: Johan HerlandNext: Johan Herland
Message 36 of 38 in “[PATCHv4 00/12] git notes”
  1. Johan HerlandAug 27, 2009
  2. 01/12 Introduce commit notesJohan Herland, Aug 27, 2009
  3. 02/12 Add a script to edit/inspect notesJohan Herland, Aug 27, 2009
  4. 03/12 Speed up git notes lookupJohan Herland, Aug 27, 2009
  5. 04/12 Add an expensive test for git-notesJohan Herland, Aug 27, 2009
  6. 05/12 Teach "-m <msg>" and "-F <file>" to "git notes edit"Johan Herland, Aug 27, 2009
  7. 06/12 fast-import: Add support for importing commit notesJohan Herland, Aug 27, 2009
  8. 07/12 t3302-notes-index-expensive: Speed up create_repo()Johan Herland, Aug 27, 2009
  9. 08/12 Teach the notes lookup code to parse notes trees with various fanout schemesJohan Herland, Aug 27, 2009
  10. Junio C HamanoAug 27, 2009
  11. Johan HerlandAug 27, 2009
  12. Johannes SchindelinAug 27, 2009
  13. Junio C HamanoAug 27, 2009
  14. Johannes SchindelinAug 28, 2009
  15. Junio C HamanoAug 27, 2009
  16. Shawn O. PearceAug 27, 2009
  17. Junio C HamanoAug 27, 2009
  18. Johan HerlandAug 27, 2009
  19. Jeff KingAug 27, 2009
  20. Junio C HamanoAug 28, 2009
  21. Sverre RabbelierAug 28, 2009
  22. Junio C HamanoAug 28, 2009
  23. Sverre RabbelierAug 28, 2009
  24. Junio C HamanoAug 28, 2009
  25. Sverre RabbelierAug 28, 2009
  26. Junio C HamanoAug 28, 2009
  27. Johannes SchindelinAug 28, 2009
  28. Johan HerlandAug 28, 2009
  29. Johannes SchindelinAug 28, 2009
  30. Johan HerlandAug 28, 2009
  31. Johannes SchindelinAug 27, 2009
  32. 09/12 Selftests verifying semantics when loading notes trees with various fanoutsJohan Herland, Aug 27, 2009
  33. 10/12 notes.c: Implement simple memory pooling of leaf nodesJohan Herland, Aug 27, 2009
  34. Alex RiesenAug 27, 2009
  35. Johan HerlandAug 27, 2009
  36. Johan HerlandAug 27, 2009
  37. 11/12 Add flags to get_commit_notes() to control the format of the note stringJohan Herland, Aug 27, 2009
  38. 12/12 Add '%N'-format for pretty-printing commit notesJohan Herland, Aug 27, 2009

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