Abhishek Kumar <abhishekkumar8222@xxxxxxxxx> 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. Very minor nitpick: this sentence would read better if the names of `generation` and `graph_pos` fields (but especially the 'generation') were quoted. > > This wastage would have been more pronounced as transistion to > generation number v2, which uses 64-bit generation number instead of > current 32-bits. Good. Moving reachability index value into a commit slab was one of prerequisites to switching to the generation number v2, see [2] [2]: https://public-inbox.org/git/cfa2c367-5cd7-add5-0293-caa75b103f34@xxxxxxxxx/t/#u The other prerequisite was proper handling of commit-graph format change, either by using "metadata chunk" as more flexible replacement of mishandled format version field in the commit-graph file header, or as proposed in [3] (and subsequent posts), removing "CDAT" chunk and replacing it with "CDA2" chunk. [3]: https://public-inbox.org/git/xmqq369z7i1b.fsf@xxxxxxxxxxxxxxxxxxxxxx/t/#u Also, we should probably stop mishandling the format version field, that is do not error out [4] when commit-graph version of the file does not match version supported by git code running the command, but just simply not use the commit-graph (like it is done for Bloom filter chunks). [4]: https://github.com/git/git/blob/master/commit-graph.c#L253 > > The third patch ("commit: convert commit->graph_pos to a slab", > 2020-06-04) is currently failing diff-submodule related tests (t4041, > t4059 and t4060) for gcc [1]. I am going to send a second version soon, > fixing that. > > [1]: https://travis-ci.com/github/abhishekkumar2718/git/jobs/343441189 > > Abhishek Kumar (3): > commit: introduce helpers for generation slab > commit: convert commit->generation to a slab > commit: convert commit->graph_pos to a slab > > alloc.c | 2 - > blame.c | 2 +- > bloom.c | 6 +- > commit-graph.c | 116 +++++++++++++++++++++------- > commit-graph.h | 8 ++ > commit-reach.c | 50 ++++++------ > commit.c | 6 +- > commit.h | 6 -- > contrib/coccinelle/generation.cocci | 12 +++ > contrib/coccinelle/graph_pos.cocci | 12 +++ It is nice to see the use of Coccinelle scripts. > revision.c | 16 ++-- > 11 files changed, 158 insertions(+), 78 deletions(-) > create mode 100644 contrib/coccinelle/generation.cocci > create mode 100644 contrib/coccinelle/graph_pos.cocci Best, -- Jakub Narębski
