[GSoC Patch 1/3] commit: introduce helpers for generation slab
- From
Abhishek Kumar <abhishekkumar8222@gmail.com>
- Date
- Jun 4, 2020, 07:27 UTC
- Message-ID
- <20200604072759.19142-2-abhishekkumar8222@gmail.com>
- In-Reply-To
- <20200604072759.19142-1-abhishekkumar8222@gmail.com>
The struct member generation refers to "generation number" (or more broadly, a reachablity index value) used by commit-graph to reduce time taken to walk commits. However, generation is not useful in other contexts and bloats the struct.
Let's move it to a commit-slab and shrink the struct by four bytes.
Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com> --- commit-graph.c | 27 +++++++++++++++++++++++++++ commit-graph.h | 5 +++++ commit.h | 3 --- 3 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/commit-graph.c b/commit-graph.c index e3420ddcbf..63f419048d 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -87,6 +87,33 @@ static int commit_pos_cmp(const void *va, const void *vb) commit_pos_at(&commit_pos, b); } +define_commit_slab(generation_slab, uint32_t); +static struct generation_slab generation_slab = COMMIT_SLAB_INIT(1, generation_slab); + +uint32_t generation(const struct commit *c) +{ + uint32_t *gen = generation_slab_peek(&generation_slab, c); + + return gen ? *gen : GENERATION_NUMBER_INFINITY; +} + +static void set_generation(const struct commit *c, const uint32_t generation) +{ + unsigned int i = generation_slab.slab_count; + uint32_t *gen = generation_slab_at(&generation_slab, c); + + /* + * commit-slab initializes with zero, overwrite this with + * GENERATION_NUMBER_INFINITY + */ + for (; i < generation_slab.slab_count; ++i) { + memset(generation_slab.slab[i], GENERATION_NUMBER_INFINITY, + generation_slab.slab_size * sizeof(uint32_t)); + } + + *gen = generation; +} + static int commit_gen_cmp(const void *va, const void *vb) { const struct commit *a = *(const struct commit **)va; diff --git a/commit-graph.h b/commit-graph.h index 4212766a4f..653bd041ad 100644 --- a/commit-graph.h +++ b/commit-graph.h @@ -8,6 +8,10 @@ #include "object-store.h" #include "oidset.h" +#define GENERATION_NUMBER_INFINITY 0xFFFFFFFF +#define GENERATION_NUMBER_MAX 0x3FFFFFFF +#define GENERATION_NUMBER_ZERO 0 + #define GIT_TEST_COMMIT_GRAPH "GIT_TEST_COMMIT_GRAPH" #define GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD" #define GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS "GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS" @@ -137,4 +141,5 @@ void free_commit_graph(struct commit_graph *); */ void disable_commit_graph(struct repository *r); +uint32_t generation(const struct commit *c); #endif diff --git a/commit.h b/commit.h index 1b2dea5d85..cc610400d5 100644 --- a/commit.h +++ b/commit.h @@ -11,9 +11,6 @@ #include "commit-slab.h" #define COMMIT_NOT_FROM_GRAPH 0xFFFFFFFF -#define GENERATION_NUMBER_INFINITY 0xFFFFFFFF -#define GENERATION_NUMBER_MAX 0x3FFFFFFF -#define GENERATION_NUMBER_ZERO 0 struct commit_list { struct commit *item;
-- 2.27.0