From c2bc6e6ab0ade70c475a73d06326e677e70840d2 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 18 Jun 2019 11:14:32 -0700 Subject: [PATCH] commit-graph: create options for split files The split commit-graph feature is now fully implemented, but needs some more run-time configurability. Allow direct callers to 'git commit-graph write --split' to specify the values used in the merge strategy and the expire time. Update the documentation to specify these values. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- Documentation/git-commit-graph.txt | 21 ++++++++++- Documentation/technical/commit-graph.txt | 7 ++-- builtin/commit-graph.c | 25 ++++++++++--- builtin/commit.c | 2 +- builtin/gc.c | 3 +- commit-graph.c | 35 ++++++++++++------ commit-graph.h | 12 +++++- t/t5324-split-commit-graph.sh | 47 ++++++++++++++++++++++++ 8 files changed, 128 insertions(+), 24 deletions(-) diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt index 624470e198..365e145e82 100644 --- a/Documentation/git-commit-graph.txt +++ b/Documentation/git-commit-graph.txt @@ -26,7 +26,7 @@ OPTIONS Use given directory for the location of packfiles and commit-graph file. This parameter exists to specify the location of an alternate that only has the objects directory, not a full `.git` directory. The - commit-graph file is expected to be at `/info/commit-graph` and + commit-graph file is expected to be in the `/info` directory and the packfiles are expected to be in `/pack`. @@ -51,6 +51,25 @@ or `--stdin-packs`.) + With the `--append` option, include all commits that are present in the existing commit-graph file. ++ +With the `--split` option, write the commit-graph as a chain of multiple +commit-graph files stored in `/info/commit-graphs`. The new commits +not already in the commit-graph are added in a new "tip" file. This file +is merged with the existing file if the following merge conditions are +met: ++ +* If `--size-multiple=` is not specified, let `X` equal 2. If the new +tip file would have `N` commits and the previous tip has `M` commits and +`X` times `N` is greater than `M`, instead merge the two files into a +single file. ++ +* If `--max-commits=` is specified with `M` a positive integer, and the +new tip file would have more than `M` commits, then instead merge the new +tip with the previous tip. ++ +Finally, if `--expire-time=` is not specified, let `datetime` +be the current time. After writing the split commit-graph, delete all +unused commit-graph whose modified times are older than `datetime`. 'read':: diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt index aed4350a59..729fbcb32f 100644 --- a/Documentation/technical/commit-graph.txt +++ b/Documentation/technical/commit-graph.txt @@ -248,10 +248,11 @@ When writing a set of commits that do not exist in the commit-graph stack of height N, we default to creating a new file at level N + 1. We then decide to merge with the Nth level if one of two conditions hold: - 1. The expected file size for level N + 1 is at least half the file size for - level N. + 1. `--size-multiple=` is specified or X = 2, and the number of commits in + level N is less than X times the number of commits in level N + 1. - 2. Level N + 1 contains more than 64,0000 commits. + 2. `--max-commits=` is specified with non-zero C and the number of commits + in level N + 1 is more than C commits. This decision cascades down the levels: when we merge a level we create a new set of commits that then compares to the next level. diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c index ff8bc3c8b9..6c0b5b17e0 100644 --- a/builtin/commit-graph.c +++ b/builtin/commit-graph.c @@ -10,7 +10,7 @@ static char const * const builtin_commit_graph_usage[] = { N_("git commit-graph [--object-dir ]"), N_("git commit-graph read [--object-dir ]"), N_("git commit-graph verify [--object-dir ]"), - N_("git commit-graph write [--object-dir ] [--append|--split] [--reachable|--stdin-packs|--stdin-commits]"), + N_("git commit-graph write [--object-dir ] [--append|--split] [--reachable|--stdin-packs|--stdin-commits] "), NULL }; @@ -25,7 +25,7 @@ static const char * const builtin_commit_graph_read_usage[] = { }; static const char * const builtin_commit_graph_write_usage[] = { - N_("git commit-graph write [--object-dir ] [--append|--split] [--reachable|--stdin-packs|--stdin-commits]"), + N_("git commit-graph write [--object-dir ] [--append|--split] [--reachable|--stdin-packs|--stdin-commits] "), NULL }; @@ -135,6 +135,7 @@ static int graph_read(int argc, const char **argv) } extern int read_replace_refs; +static struct split_commit_graph_opts split_opts; static int graph_write(int argc, const char **argv) { @@ -158,9 +159,19 @@ static int graph_write(int argc, const char **argv) N_("include all commits already in the commit-graph file")), OPT_BOOL(0, "split", &opts.split, N_("allow writing an incremental commit-graph file")), + OPT_INTEGER(0, "max-commits", &split_opts.max_commits, + N_("maximum number of commits in a non-base split commit-graph")), + OPT_INTEGER(0, "size-multiple", &split_opts.size_multiple, + N_("maximum ratio between two levels of a split commit-graph")), + OPT_EXPIRY_DATE(0, "expire-time", &split_opts.expire_time, + N_("maximum number of commits in a non-base split commit-graph")), OPT_END(), }; + split_opts.size_multiple = 2; + split_opts.max_commits = 0; + split_opts.expire_time = 0; + argc = parse_options(argc, argv, NULL, builtin_commit_graph_write_options, builtin_commit_graph_write_usage, 0); @@ -176,8 +187,11 @@ static int graph_write(int argc, const char **argv) read_replace_refs = 0; - if (opts.reachable) - return write_commit_graph_reachable(opts.obj_dir, flags); + if (opts.reachable) { + if (write_commit_graph_reachable(opts.obj_dir, flags, &split_opts)) + return 1; + return 0; + } string_list_init(&lines, 0); if (opts.stdin_packs || opts.stdin_commits) { @@ -197,7 +211,8 @@ static int graph_write(int argc, const char **argv) if (write_commit_graph(opts.obj_dir, pack_indexes, commit_hex, - flags)) + flags, + &split_opts)) result = 1; UNLEAK(lines); diff --git a/builtin/commit.c b/builtin/commit.c index b001ef565d..9216e9c043 100644 --- a/builtin/commit.c +++ b/builtin/commit.c @@ -1670,7 +1670,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix) "not exceeded, and then \"git reset HEAD\" to recover.")); if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) && - write_commit_graph_reachable(get_object_directory(), 0)) + write_commit_graph_reachable(get_object_directory(), 0, NULL)) return 1; repo_rerere(the_repository, 0); diff --git a/builtin/gc.c b/builtin/gc.c index 20c8f1bfe8..0aa8eac747 100644 --- a/builtin/gc.c +++ b/builtin/gc.c @@ -666,7 +666,8 @@ int cmd_gc(int argc, const char **argv, const char *prefix) if (gc_write_commit_graph && write_commit_graph_reachable(get_object_directory(), - !quiet && !daemonized ? COMMIT_GRAPH_PROGRESS : 0)) + !quiet && !daemonized ? COMMIT_GRAPH_PROGRESS : 0, + NULL)) return 1; if (auto_gc && too_many_loose_objects()) diff --git a/commit-graph.c b/commit-graph.c index 0cc2ceb349..315088d205 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -768,6 +768,8 @@ struct write_commit_graph_context { unsigned append:1, report_progress:1, split:1; + + const struct split_commit_graph_opts *split_opts; }; static void write_graph_chunk_fanout(struct hashfile *f, @@ -1116,14 +1118,15 @@ static int add_ref_to_list(const char *refname, return 0; } -int write_commit_graph_reachable(const char *obj_dir, unsigned int flags) +int write_commit_graph_reachable(const char *obj_dir, unsigned int flags, + const struct split_commit_graph_opts *split_opts) { struct string_list list = STRING_LIST_INIT_DUP; int result; for_each_ref(add_ref_to_list, &list); result = write_commit_graph(obj_dir, NULL, &list, - flags); + flags, split_opts); string_list_clear(&list, 0); return result; @@ -1498,20 +1501,25 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx) return 0; } -static int split_strategy_max_commits = 64000; -static float split_strategy_size_mult = 2.0f; - static void split_graph_merge_strategy(struct write_commit_graph_context *ctx) { struct commit_graph *g = ctx->r->objects->commit_graph; uint32_t num_commits = ctx->commits.nr; uint32_t i; + int max_commits = 0; + int size_mult = 2; + + if (ctx->split_opts) { + max_commits = ctx->split_opts->max_commits; + size_mult = ctx->split_opts->size_multiple; + } + g = ctx->r->objects->commit_graph; ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1; - while (g && (g->num_commits <= split_strategy_size_mult * num_commits || - num_commits > split_strategy_max_commits)) { + while (g && (g->num_commits <= size_mult * num_commits || + (max_commits && num_commits > max_commits))) { if (strcmp(g->obj_dir, ctx->obj_dir)) break; @@ -1675,7 +1683,10 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx) DIR *dir; struct dirent *de; size_t dirnamelen; - time_t expire_time = time(NULL); + timestamp_t expire_time = time(NULL); + + if (ctx->split_opts && ctx->split_opts->expire_time) + expire_time -= ctx->split_opts->expire_time; strbuf_addstr(&path, ctx->obj_dir); strbuf_addstr(&path, "/info/commit-graphs"); @@ -1719,7 +1730,8 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx) int write_commit_graph(const char *obj_dir, struct string_list *pack_indexes, struct string_list *commit_hex, - unsigned int flags) + unsigned int flags, + const struct split_commit_graph_opts *split_opts) { struct write_commit_graph_context *ctx; uint32_t i, count_distinct = 0; @@ -1734,6 +1746,7 @@ int write_commit_graph(const char *obj_dir, ctx->append = flags & COMMIT_GRAPH_APPEND ? 1 : 0; ctx->report_progress = flags & COMMIT_GRAPH_PROGRESS ? 1 : 0; ctx->split = flags & COMMIT_GRAPH_SPLIT ? 1 : 0; + ctx->split_opts = split_opts; if (ctx->split) { struct commit_graph *g; @@ -1761,8 +1774,8 @@ int write_commit_graph(const char *obj_dir, ctx->approx_nr_objects = approximate_object_count(); ctx->oids.alloc = ctx->approx_nr_objects / 32; - if (ctx->split && ctx->oids.alloc > split_strategy_max_commits) - ctx->oids.alloc = split_strategy_max_commits; + if (ctx->split && split_opts && ctx->oids.alloc > split_opts->max_commits) + ctx->oids.alloc = split_opts->max_commits; if (ctx->append) { prepare_commit_graph_one(ctx->r, ctx->obj_dir); diff --git a/commit-graph.h b/commit-graph.h index 802d35254f..a84c22a560 100644 --- a/commit-graph.h +++ b/commit-graph.h @@ -75,17 +75,25 @@ int generation_numbers_enabled(struct repository *r); #define COMMIT_GRAPH_PROGRESS (1 << 1) #define COMMIT_GRAPH_SPLIT (1 << 2) +struct split_commit_graph_opts { + int size_multiple; + int max_commits; + timestamp_t expire_time; +}; + /* * The write_commit_graph* methods return zero on success * and a negative value on failure. Note that if the repository * is not compatible with the commit-graph feature, then the * methods will return 0 without writing a commit-graph. */ -int write_commit_graph_reachable(const char *obj_dir, unsigned int flags); +int write_commit_graph_reachable(const char *obj_dir, unsigned int flags, + const struct split_commit_graph_opts *split_opts); int write_commit_graph(const char *obj_dir, struct string_list *pack_indexes, struct string_list *commit_hex, - unsigned int flags); + unsigned int flags, + const struct split_commit_graph_opts *split_opts); int verify_commit_graph(struct repository *r, struct commit_graph *g); diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh index 76068ee407..1b699a543c 100755 --- a/t/t5324-split-commit-graph.sh +++ b/t/t5324-split-commit-graph.sh @@ -169,4 +169,51 @@ test_expect_success 'create fork and chain across alternate' ' graph_git_behavior 'alternate: commit 13 vs 6' commits/13 commits/6 +test_expect_success 'test merge stragety constants' ' + git clone . merge-2 && + ( + cd merge-2 && + git config core.commitGraph true && + test_line_count = 2 $graphdir/commit-graph-chain && + test_commit 14 && + git commit-graph write --reachable --split --size-multiple=2 && + test_line_count = 3 $graphdir/commit-graph-chain + + ) && + git clone . merge-10 && + ( + cd merge-10 && + git config core.commitGraph true && + test_line_count = 2 $graphdir/commit-graph-chain && + test_commit 14 && + git commit-graph write --reachable --split --size-multiple=10 && + test_line_count = 1 $graphdir/commit-graph-chain && + ls $graphdir/graph-*.graph >graph-files && + test_line_count = 1 graph-files + ) && + git clone . merge-10-expire && + ( + cd merge-10-expire && + git config core.commitGraph true && + test_line_count = 2 $graphdir/commit-graph-chain && + test_commit 15 && + git commit-graph write --reachable --split --size-multiple=10 --expire-time=1980-01-01 && + test_line_count = 1 $graphdir/commit-graph-chain && + ls $graphdir/graph-*.graph >graph-files && + test_line_count = 3 graph-files + ) && + git clone --no-hardlinks . max-commits && + ( + cd max-commits && + git config core.commitGraph true && + test_line_count = 2 $graphdir/commit-graph-chain && + test_commit 16 && + test_commit 17 && + git commit-graph write --reachable --split --max-commits=1 && + test_line_count = 1 $graphdir/commit-graph-chain && + ls $graphdir/graph-*.graph >graph-files && + test_line_count = 1 graph-files + ) +' + test_done -- 2.47.1