remote: make add_missing_tags() linear
The add_missing_tags() method currently has quadratic behavior. This is due to a linear number (based on number of tags T) of calls to in_merge_bases_many, which has linear performance (based on number of commits C in the repository). Replace this O(T * C) algorithm with an O(T + C) algorithm by using get_reachable_subset(). We ignore the return list and focus instead on the reachable_flag assigned to the commits we care about, because we need to interact with the tag ref and not just the commit object. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee committed
Nov 2, 2018 at 06:14 UTC
85daa01f6b80cb6eb14c5f484a6da9f0b1247143
1 file changed
+33
-1
remote.c
+33
-1
@@ -1205,9 +1205,36 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
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* sent to the other side.
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*/
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if (sent_tips.nr) {
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+ const int reachable_flag = 1;
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+ struct commit_list *found_commits;
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+ struct commit **src_commits;
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+ int nr_src_commits = 0, alloc_src_commits = 16;
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+ ALLOC_ARRAY(src_commits, alloc_src_commits);
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+
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for_each_string_list_item(item, &src_tag) {
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struct ref *ref = item->util;
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+ struct commit *commit;
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+
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+ if (is_null_oid(&ref->new_oid))
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+ continue;
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+ commit = lookup_commit_reference_gently(the_repository,
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+ &ref->new_oid,
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+ 1);
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+ if (!commit)
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+ /* not pushing a commit, which is not an error */
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+ continue;
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+
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+ ALLOC_GROW(src_commits, nr_src_commits + 1, alloc_src_commits);
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+ src_commits[nr_src_commits++] = commit;
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+ }
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+
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+ found_commits = get_reachable_subset(sent_tips.tip, sent_tips.nr,
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+ src_commits, nr_src_commits,
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+ reachable_flag);
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+
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+ for_each_string_list_item(item, &src_tag) {
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struct ref *dst_ref;
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+ struct ref *ref = item->util;
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struct commit *commit;
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if (is_null_oid(&ref->new_oid))
@@ -1223,7 +1250,7 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
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* Is this tag, which they do not have, reachable from
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* any of the commits we are sending?
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*/
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- if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
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+ if (!(commit->object.flags & reachable_flag))
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continue;
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/* Add it in */
@@ -1231,7 +1258,12 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
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oidcpy(&dst_ref->new_oid, &ref->new_oid);
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dst_ref->peer_ref = copy_ref(ref);
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}
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+
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+ clear_commit_marks_many(nr_src_commits, src_commits, reachable_flag);
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+ free(src_commits);
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+ free_commit_list(found_commits);
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}
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+
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string_list_clear(&src_tag, 0);
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free(sent_tips.tip);
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}