From: jnareb@gmail.com (Jakub Narębski)
To: Abhishek Kumar <abhishekkumar8222@gmail.com>
Cc: git@vger.kernel.org, "Derrick Stolee" <stolee@gmail.com>,
"Jakub Narębski" <jnareb@gmail.com>
Subject: Re: [GSoC Patch 0/3] Move generation, graph_pos to a slab
Date: Fri, 05 Jun 2020 21:00:56 +0200 [thread overview]
Message-ID: <85ftb9wd5j.fsf@gmail.com> (raw)
In-Reply-To: <20200604072759.19142-1-abhishekkumar8222@gmail.com> (Abhishek Kumar's message of "Thu, 4 Jun 2020 12:57:56 +0530")
Abhishek Kumar <abhishekkumar8222@gmail.com> 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@gmail.com/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@gitster.c.googlers.com/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
next prev parent reply other threads:[~2020-06-05 19:01 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 7:27 [GSoC Patch 0/3] Move generation, graph_pos to a slab Abhishek Kumar
2020-06-04 7:27 ` [GSoC Patch 1/3] commit: introduce helpers for generation slab Abhishek Kumar
2020-06-04 14:36 ` Derrick Stolee
2020-06-04 17:35 ` Junio C Hamano
2020-06-05 23:23 ` Jakub Narębski
2020-06-04 7:27 ` [GSoC Patch 2/3] commit: convert commit->generation to a slab Abhishek Kumar
2020-06-04 14:27 ` Derrick Stolee
2020-06-04 17:49 ` Junio C Hamano
2020-06-06 22:03 ` Jakub Narębski
2020-06-04 7:27 ` [GSoC Patch 3/3] commit: convert commit->graph_pos " Abhishek Kumar
2020-06-07 12:12 ` Jakub Narębski
2020-06-04 14:22 ` [GSoC Patch 0/3] Move generation, graph_pos " Derrick Stolee
2020-06-04 17:55 ` Junio C Hamano
2020-06-07 19:53 ` SZEDER Gábor
2020-06-08 5:48 ` Abhishek Kumar
2020-06-08 8:36 ` SZEDER Gábor
2020-06-08 13:45 ` Derrick Stolee
2020-06-08 16:46 ` SZEDER Gábor
2020-06-08 15:21 ` Jakub Narębski
2020-06-05 19:00 ` Jakub Narębski [this message]
2020-06-07 19:32 ` [GSOC Patch v2 0/4] " Abhishek Kumar
2020-06-07 19:32 ` [GSOC Patch v2 1/4] commit-graph: introduce commit_graph_data_slab Abhishek Kumar
2020-06-15 16:27 ` Taylor Blau
2020-06-07 19:32 ` [GSOC Patch v2 2/4] commit: move members graph_pos, generation to a slab Abhishek Kumar
2020-06-08 8:26 ` SZEDER Gábor
2020-06-08 12:35 ` Derrick Stolee
2020-06-07 19:32 ` [GSOC Patch v2 3/4] commit-graph: use generation directly when writing commit-graph Abhishek Kumar
2020-06-08 16:31 ` Jakub Narębski
2020-06-15 16:31 ` Taylor Blau
2020-06-07 19:32 ` [GSOC Patch v2 4/4] commit-graph: minimize commit_graph_data_slab access Abhishek Kumar
2020-06-08 16:22 ` [GSOC Patch v2 0/4] Move generation, graph_pos to a slab Jakub Narębski
2020-06-15 16:24 ` Taylor Blau
2020-06-17 9:14 ` [GSOC Patch v4 " Abhishek Kumar
2020-06-17 9:14 ` [GSOC Patch v4 1/4] object: drop parsed_object_pool->commit_count Abhishek Kumar
2020-06-17 9:14 ` [GSOC Patch v4 2/4] commit-graph: introduce commit_graph_data_slab Abhishek Kumar
2020-06-17 9:14 ` [GSOC Patch v4 3/4] commit: move members graph_pos, generation to a slab Abhishek Kumar
2020-06-17 9:14 ` [GSOC Patch v4 4/4] commit-graph: minimize commit_graph_data_slab access Abhishek Kumar
2020-06-19 13:59 ` [GSOC Patch v4 0/4] Move generation, graph_pos to a slab Derrick Stolee
2020-06-19 17:44 ` Junio C Hamano
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