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[104.178.186.189]) by smtp.gmail.com with ESMTPSA id 199-20020a2505d0000000b00c4f175716fcsm144589ybf.20.2023.07.10.14.12.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Jul 2023 14:12:02 -0700 (PDT) Date: Mon, 10 Jul 2023 17:12:01 -0400 From: Taylor Blau To: git@vger.kernel.org Cc: Chris Torek , Derrick Stolee , Jeff King , Junio C Hamano , Patrick Steinhardt Subject: [PATCH v5 00/16] refs: implement jump lists for packed backend Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Here is another reroll of my series to implement jump (née skip) lists for the packed refs backend, based on top of the current 'master'. This responds to a review of the entire series that Peff gave a couple of weeks ago[1], which should satisfy all of the comments that he raised, most of which were relatively minor. The notable changes from last time are: - clarifying some commit messages, notably to explicitly state that certain clean-ups do not indicate existing bugs, but are defensive against potential future ones - polishing up some of the API changes, to avoid having `match_name_as_path()` take a ref_filter pointer. - more timing data and documentation in the first substantive patch - clean-up in the upload-pack.c to make the changes clearer As usual, a range-diff is included below for convenience. Thanks in advance for your review! [1]: https://lore.kernel.org/git/20230703062925.GK3502534@coredump.intra.peff.net/ Jeff King (5): refs.c: rename `ref_filter` ref-filter.h: provide `REF_FILTER_INIT` ref-filter: clear reachable list pointers after freeing ref-filter: add `ref_filter_clear()` ref-filter.c: parameterize match functions over patterns Taylor Blau (11): builtin/for-each-ref.c: add `--exclude` option refs: plumb `exclude_patterns` argument throughout refs/packed-backend.c: refactor `find_reference_location()` refs/packed-backend.c: implement jump lists to avoid excluded pattern(s) refs/packed-backend.c: add trace2 counters for jump list revision.h: store hidden refs in a `strvec` refs.h: let `for_each_namespaced_ref()` take excluded patterns refs.h: implement `hidden_refs_to_excludes()` builtin/receive-pack.c: avoid enumerating hidden references upload-pack.c: avoid enumerating hidden refs where possible ls-refs.c: avoid enumerating hidden refs where possible Documentation/git-for-each-ref.txt | 6 + builtin/branch.c | 4 +- builtin/for-each-ref.c | 7 +- builtin/receive-pack.c | 8 +- builtin/tag.c | 4 +- http-backend.c | 2 +- ls-refs.c | 7 +- ref-filter.c | 66 +++++++--- ref-filter.h | 12 ++ refs.c | 85 ++++++++---- refs.h | 29 +++- refs/debug.c | 5 +- refs/files-backend.c | 5 +- refs/packed-backend.c | 204 +++++++++++++++++++++++++---- refs/refs-internal.h | 7 +- revision.c | 4 +- revision.h | 5 +- t/helper/test-reach.c | 2 +- t/helper/test-ref-store.c | 10 ++ t/t0041-usage.sh | 1 + t/t1419-exclude-refs.sh | 122 +++++++++++++++++ t/t3402-rebase-merge.sh | 1 + t/t6300-for-each-ref.sh | 35 +++++ trace2.h | 2 + trace2/tr2_ctr.c | 5 + upload-pack.c | 47 +++++-- 26 files changed, 579 insertions(+), 106 deletions(-) create mode 100755 t/t1419-exclude-refs.sh Range-diff against v4: 1: c12def5a30a ! 1: 5b5ccc40d6b refs.c: rename `ref_filter` @@ Commit message refs.c: rename `ref_filter` The refs machinery has its own implementation of a `ref_filter` (used by - `for-each-ref`), which is distinct from the `ref-filler.h` API (also + `for-each-ref`), which is distinct from the `ref-filter.h` API (also used by `for-each-ref`, among other things). Rename the one within refs.c to more clearly indicate its purpose. 2: 7ce82b6a5a4 ! 2: 0c4e995f1d3 ref-filter.h: provide `REF_FILTER_INIT` @@ Commit message Provide a sane initialization value for `struct ref_filter`, which in a subsequent patch will be used to initialize a new field. - In the meantime, fix a case in test-reach.c where its `ref_filter` is - not even zero-initialized. + In the meantime, ensure that the `ref_filter` struct used in the + test-helper's `cmd__reach()` is zero-initialized. The lack of + initialization is OK, since `commit_contains()` only looks at the single + `with_commit_tag_algo` field that *is* initialized directly above. + + So this does not fix a bug, but rather prevents one from biting us in + the future. Signed-off-by: Jeff King Signed-off-by: Taylor Blau 3: 7e6bf7766d0 ! 3: cea1e88d358 ref-filter: clear reachable list pointers after freeing @@ Metadata ## Commit message ## ref-filter: clear reachable list pointers after freeing - In reach_filter(), we pop all commits from the reachable lists, leaving - them empty. But because we're operating on a list pointer that was - passed by value, the original filter.reachable_from pointer is left - dangling. + In `reach_filter()`, we pop all commits from the reachable lists, + leaving them empty. But because we're operating on a list pointer that + was passed by value, the original `filter.reachable_from` and + `filter.unreachable_from` pointers are left dangling. + + As is the case with the previous commit, nobody touches either of these + fields after calling `reach_filter()`, so leaving them dangling is OK. + But this future proofs against dangerous situations. Signed-off-by: Jeff King Signed-off-by: Taylor Blau 4: 777e71004d6 = 4: 00a4532d54d ref-filter: add `ref_filter_clear()` 5: 39e9b0f50d0 ! 5: 3ab03ac20df ref-filter.c: parameterize match functions over patterns @@ ref-filter.c: static int get_ref_atom_value(struct ref_array_item *ref, int atom */ -static int match_pattern(const struct ref_filter *filter, const char *refname) +static int match_pattern(const char **patterns, const char *refname, -+ const int ignore_case) ++ int ignore_case) { - const char **patterns = filter->name_patterns; unsigned flags = 0; @@ ref-filter.c: static int match_pattern(const struct ref_filter *filter, const ch * wildcard (e.g. the same ref matches "refs/heads/m*", too). */ -static int match_name_as_path(const struct ref_filter *filter, const char *refname) -+static int match_name_as_path(const struct ref_filter *filter, -+ const char **pattern, -+ const char *refname) ++static int match_name_as_path(const char **pattern, const char *refname, ++ int ignore_case) { - const char **pattern = filter->name_patterns; int namelen = strlen(refname); unsigned flags = WM_PATHNAME; +- if (filter->ignore_case) ++ if (ignore_case) + flags |= WM_CASEFOLD; + + for (; *pattern; pattern++) { @@ ref-filter.c: static int filter_pattern_match(struct ref_filter *filter, const char *refname) if (!*filter->name_patterns) return 1; /* No pattern always matches */ if (filter->match_as_path) - return match_name_as_path(filter, refname); - return match_pattern(filter, refname); -+ return match_name_as_path(filter, filter->name_patterns, refname); ++ return match_name_as_path(filter->name_patterns, refname, ++ filter->ignore_case); + return match_pattern(filter->name_patterns, refname, + filter->ignore_case); } 6: c4fd47fd750 ! 6: aa881ca06fa builtin/for-each-ref.c: add `--exclude` option @@ ref-filter.c: static int filter_pattern_match(struct ref_filter *filter, const c + if (!filter->exclude.nr) + return 0; + if (filter->match_as_path) -+ return match_name_as_path(filter, filter->exclude.v, refname); ++ return match_name_as_path(filter->exclude.v, refname, ++ filter->ignore_case); + return match_pattern(filter->exclude.v, refname, filter->ignore_case); +} + 7: e6b50c50219 = 7: 81e223de0c8 refs: plumb `exclude_patterns` argument throughout 8: a0990b2916c = 8: 25c099a528c refs/packed-backend.c: refactor `find_reference_location()` 9: 386ed468fa7 ! 9: af0ce43cc90 refs/packed-backend.c: implement jump lists to avoid excluded pattern(s) @@ Commit message $ hyperfine \ 'git for-each-ref --format="%(objectname) %(refname)" | grep -vE "^[0-9a-f]{40} refs/pull/"' \ + 'git.prev for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull"' \ 'git.compile for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull"' Benchmark 1: git for-each-ref --format="%(objectname) %(refname)" | grep -vE "^[0-9a-f]{40} refs/pull/" - Time (mean ± σ): 802.7 ms ± 2.1 ms [User: 691.6 ms, System: 147.0 ms] - Range (min … max): 800.0 ms … 807.7 ms 10 runs + Time (mean ± σ): 798.1 ms ± 3.3 ms [User: 687.6 ms, System: 146.4 ms] + Range (min … max): 794.5 ms … 805.5 ms 10 runs - Benchmark 2: git.compile for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull" - Time (mean ± σ): 4.7 ms ± 0.3 ms [User: 0.7 ms, System: 4.0 ms] - Range (min … max): 4.3 ms … 6.7 ms 422 runs + Benchmark 2: git.prev for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull" + Time (mean ± σ): 98.9 ms ± 1.4 ms [User: 93.1 ms, System: 5.7 ms] + Range (min … max): 97.0 ms … 104.0 ms 29 runs + + Benchmark 3: git.compile for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull" + Time (mean ± σ): 4.5 ms ± 0.2 ms [User: 0.7 ms, System: 3.8 ms] + Range (min … max): 4.1 ms … 5.8 ms 524 runs Summary 'git.compile for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull"' ran - 172.03 ± 9.60 times faster than 'git for-each-ref --format="%(objectname) %(refname)" | grep -vE "^[0-9a-f]{40} refs/pull/"' + 21.87 ± 1.05 times faster than 'git.prev for-each-ref --format="%(objectname) %(refname)" --exclude="refs/pull"' + 176.52 ± 8.19 times faster than 'git for-each-ref --format="%(objectname) %(refname)" | grep -vE "^[0-9a-f]{40} refs/pull/"' + + (Comparing stock git and this patch isn't quite fair, since an earlier + commit in this series adds a naive implementation of the `--exclude` + option. `git.prev` is built from the previous commit and includes this + naive implementation). Using the jump list is fairly straightforward (see the changes to `refs/packed-backend.c::next_record()`), but constructing the list is @@ ref-filter.c: static int for_each_fullref_in_pattern(struct ref_filter *filter, /* + ## refs.h ## +@@ refs.h: int for_each_ref(each_ref_fn fn, void *cb_data); + */ + int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data); + ++/* ++ * references matching any pattern in "exclude_patterns" are omitted from the ++ * result set on a best-effort basis. ++ */ + int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix, + const char **exclude_patterns, + each_ref_fn fn, void *cb_data); + ## refs/packed-backend.c ## @@ refs/packed-backend.c: static int cmp_packed_ref_records(const void *v1, const void *v2) * Compare a snapshot record at `rec` to the specified NUL-terminated @@ refs/packed-backend.c: struct packed_ref_iterator { + iter->jump_cur++; + if (iter->pos < curr->end) { + iter->pos = curr->end; ++ /* jumps are coalesced, so only one jump is necessary */ + break; + } + } @@ refs/packed-backend.c: static struct ref_iterator_vtable packed_ref_iterator_vta + + for (pattern = excluded_patterns; *pattern; pattern++) { + struct jump_list_entry *e; ++ const char *start, *end; + + /* + * We can't feed any excludes with globs in them to the @@ refs/packed-backend.c: static struct ref_iterator_vtable packed_ref_iterator_vta + if (has_glob_special(*pattern)) + continue; + ++ start = find_reference_location(snapshot, *pattern, 0); ++ end = find_reference_location_end(snapshot, *pattern, 0); ++ ++ if (start == end) ++ continue; /* nothing to jump over */ ++ + ALLOC_GROW(iter->jump, iter->jump_nr + 1, iter->jump_alloc); + + e = &iter->jump[iter->jump_nr++]; -+ e->start = find_reference_location(snapshot, *pattern, 0); -+ e->end = find_reference_location_end(snapshot, *pattern, 0); ++ e->start = start; ++ e->end = end; + } + + if (!iter->jump_nr) { @@ refs/packed-backend.c: static struct ref_iterator_vtable packed_ref_iterator_vta + + for (i = 1, j = 1; i < iter->jump_nr; i++) { + struct jump_list_entry *ours = &iter->jump[i]; -+ -+ if (ours->start == ours->end) { -+ /* ignore empty regions (no matching entries) */ -+ continue; -+ } else if (ours->start <= last_disjoint->end) { ++ if (ours->start <= last_disjoint->end) { + /* overlapping regions extend the previous one */ + last_disjoint->end = last_disjoint->end > ours->end + ? last_disjoint->end : ours->end; @@ refs/packed-backend.c: static struct ref_iterator_vtable packed_ref_iterator_vta + /* otherwise, insert a new region */ + iter->jump[j++] = *ours; + last_disjoint = ours; -+ + } + } + 10: 49c8f5173aa ! 10: e150941c1d1 refs/packed-backend.c: add trace2 counters for jump list @@ Commit message ## refs/packed-backend.c ## @@ - #include "../chdir-notify.h" + #include "../statinfo.h" #include "../wrapper.h" #include "../write-or-die.h" +#include "../trace2.h" @@ refs/packed-backend.c: static int next_record(struct packed_ref_iterator *iter) if (iter->pos < curr->end) { iter->pos = curr->end; + trace2_counter_add(TRACE2_COUNTER_ID_PACKED_REFS_JUMPS, 1); + /* jumps are coalesced, so only one jump is necessary */ break; } - } ## t/t1419-exclude-refs.sh ## @@ t/t1419-exclude-refs.sh: TEST_PASSES_SANITIZE_LEAK=true 11: dd856a3982b = 11: a5093d52008 revision.h: store hidden refs in a `strvec` 12: 845904853ee < -: ----------- refs/packed-backend.c: ignore complicated hidden refs rules 13: 8d4d7cc22ee ! 12: 7e72c23c8a4 refs.h: let `for_each_namespaced_ref()` take excluded patterns @@ refs.h: int for_each_glob_ref_in(each_ref_fn fn, const char *pattern, int head_ref_namespaced(each_ref_fn fn, void *cb_data); -int for_each_namespaced_ref(each_ref_fn fn, void *cb_data); ++/* ++ * references matching any pattern in "exclude_patterns" are omitted from the ++ * result set on a best-effort basis. ++ */ +int for_each_namespaced_ref(const char **exclude_patterns, + each_ref_fn fn, void *cb_data); -: ----------- > 13: f99d89d53b9 refs.h: implement `hidden_refs_to_excludes()` 14: 49c665f9f8f ! 14: 96aada36f9b builtin/receive-pack.c: avoid enumerating hidden references @@ builtin/receive-pack.c: static void write_head_info(void) - for_each_ref(show_ref_cb, &seen); + refs_for_each_fullref_in(get_main_ref_store(the_repository), "", -+ hidden_refs.v, show_ref_cb, &seen); ++ hidden_refs_to_excludes(&hidden_refs), ++ show_ref_cb, &seen); for_each_alternate_ref(show_one_alternate_ref, &seen); oidset_clear(&seen); if (!sent_capabilities) 15: 19bf4a52d69 ! 15: 8544a647798 upload-pack.c: avoid enumerating hidden refs where possible @@ upload-pack.c: static int get_common_commits(struct upload_pack_data *data, +static int allow_hidden_refs(enum allow_uor allow_uor) +{ -+ return allow_uor & (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1); ++ if ((allow_uor & ALLOW_ANY_SHA1) == ALLOW_ANY_SHA1) ++ return 1; ++ return !(allow_uor & (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1)); +} + +static void for_each_namespaced_ref_1(each_ref_fn fn, + struct upload_pack_data *data) +{ ++ const char **excludes = NULL; + /* + * If `data->allow_uor` allows fetching hidden refs, we need to + * mark all references (including hidden ones), to check in @@ upload-pack.c: static int get_common_commits(struct upload_pack_data *data, + * hidden references. + */ + if (allow_hidden_refs(data->allow_uor)) -+ for_each_namespaced_ref(NULL, fn, data); -+ else -+ for_each_namespaced_ref(data->hidden_refs.v, fn, data); ++ excludes = hidden_refs_to_excludes(&data->hidden_refs); ++ ++ for_each_namespaced_ref(excludes, fn, data); +} ++ + static int is_our_ref(struct object *o, enum allow_uor allow_uor) { - int allow_hidden_ref = (allow_uor & - (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1)); - return o->flags & ((allow_hidden_ref ? HIDDEN_REF : 0) | OUR_REF); -+ return o->flags & ((allow_hidden_refs(allow_uor) ? HIDDEN_REF : 0) | OUR_REF); ++ return o->flags & ((allow_hidden_refs(allow_uor) ? 0 : HIDDEN_REF) | OUR_REF); } /* 16: ea6cbaf292f ! 16: dff068c469f ls-refs.c: avoid enumerating hidden refs where possible @@ ls-refs.c: int ls_refs(struct repository *r, struct packet_reader *request) refs_for_each_fullref_in_prefixes(get_main_ref_store(r), get_git_namespace(), data.prefixes.v, - NULL, send_ref, &data); -+ data.hidden_refs.v, send_ref, &data); ++ hidden_refs_to_excludes(&data.hidden_refs), ++ send_ref, &data); packet_fflush(stdout); strvec_clear(&data.prefixes); strbuf_release(&data.buf);