Re: [GSOC Patch v2 0/4] Move generation, graph_pos to a slab

Abhishek Kumar [off-list ref] writes:

The struct commit is used in many contexts. However, members
`generation` and `graph_pos` are only used for commit graph related
operations and otherwise waste memory.

This wastage would have been more pronounced as we transition to
generation number v2, which uses 64-bite generation number instead of
current 32-bits.

It would be nice (though not required) to have some specific data:
benchmarks with time and memory (RSS maybe?) of Git commands using
commit-graph and those not using it, before and after this patch series.
Maybe time to run the test suite, or the perf suite...

But this is not a show stopper, in my opinion.

Best,

  Jakub Narębski

Abhishek Kumar (4):
  commit-graph: introduce commit_graph_data_slab
  commit: move members graph_pos, generation to a slab
  commit-graph: use generation directly when writing commit-graph
  commit-graph: minimize commit_graph_data_slab access

 alloc.c                         |   2 -
 blame.c                         |   2 +-
 bloom.c                         |   7 +-
 commit-graph.c                  | 127 ++++++++++++++++++++++++--------
 commit-graph.h                  |  10 +++
 commit-reach.c                  |  69 ++++++++++-------
 commit.c                        |   8 +-
 contrib/coccinelle/commit.cocci |  18 +++++
 revision.c                      |  20 +++--
 9 files changed, 190 insertions(+), 73 deletions(-)