[PATCH] clear_commit_marks(): avoid deep recursion
From: Johannes Schindelin <hidden>
Date: 2016-06-15 22:43:40
Subsystem:
the rest · Maintainer:
Linus Torvalds
Before this patch, clear_commit_marks() recursed for each parent. This could be potentially very expensive in terms of stack space. Probably the only reason that this did not lead to problems is the fact that we typically call clear_commit_marks() after marking a relatively small set of commits. Use (sort of) a tail recursion instead: first recurse on the parents other than the first one, and then continue the loop with the first parent. Noticed by Shawn Pearce. Signed-off-by: Johannes Schindelin <redacted> --- commit.c | 23 ++++++++++++++--------- 1 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/commit.c b/commit.c
index 20fb220..ac24266 100644
--- a/commit.c
+++ b/commit.c@@ -441,17 +441,22 @@ struct commit *pop_most_recent_commit(struct commit_list **list, void clear_commit_marks(struct commit *commit, unsigned int mark) { - struct commit_list *parents; + while (commit) { + struct commit_list *parents; - commit->object.flags &= ~mark; - parents = commit->parents; - while (parents) { - struct commit *parent = parents->item; + if (!(mark & commit->object.flags)) + return; - /* Have we already cleared this? */ - if (mark & parent->object.flags) - clear_commit_marks(parent, mark); - parents = parents->next; + commit->object.flags &= ~mark; + + parents = commit->parents; + if (!parents) + return; + + while ((parents = parents->next)) + clear_commit_marks(parents->item, mark); + + commit = commit->parents->item; } }
--
1.5.3.4.1169.g5fb8d