Fix quadratic performance in rewrite_one.

Parent commits are usually older than their children. Thus,
on each iteration of the loop in rewrite_one, add_parents_to_list
traverses all commits previously processed by the loop.
It performs very poorly in case of very long rewrite chains.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Alexander N. Gavrilov 2008-07-12 22:00:57 +04:00 committed by Junio C Hamano
parent e09c4e753c
commit fce87ae538

View File

@ -412,10 +412,26 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
commit->object.flags |= TREESAME; commit->object.flags |= TREESAME;
} }
static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list) static void insert_by_date_cached(struct commit *p, struct commit_list **head,
struct commit_list *cached_base, struct commit_list **cache)
{
struct commit_list *new_entry;
if (cached_base && p->date < cached_base->item->date)
new_entry = insert_by_date(p, &cached_base->next);
else
new_entry = insert_by_date(p, head);
if (cache && (!*cache || p->date < (*cache)->item->date))
*cache = new_entry;
}
static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
struct commit_list **list, struct commit_list **cache_ptr)
{ {
struct commit_list *parent = commit->parents; struct commit_list *parent = commit->parents;
unsigned left_flag; unsigned left_flag;
struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
if (commit->object.flags & ADDED) if (commit->object.flags & ADDED)
return 0; return 0;
@ -445,7 +461,7 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit, str
if (p->object.flags & SEEN) if (p->object.flags & SEEN)
continue; continue;
p->object.flags |= SEEN; p->object.flags |= SEEN;
insert_by_date(p, list); insert_by_date_cached(p, list, cached_base, cache_ptr);
} }
return 0; return 0;
} }
@ -470,7 +486,7 @@ static int add_parents_to_list(struct rev_info *revs, struct commit *commit, str
p->object.flags |= left_flag; p->object.flags |= left_flag;
if (!(p->object.flags & SEEN)) { if (!(p->object.flags & SEEN)) {
p->object.flags |= SEEN; p->object.flags |= SEEN;
insert_by_date(p, list); insert_by_date_cached(p, list, cached_base, cache_ptr);
} }
if(revs->first_parent_only) if(revs->first_parent_only)
break; break;
@ -611,7 +627,7 @@ static int limit_list(struct rev_info *revs)
if (revs->max_age != -1 && (commit->date < revs->max_age)) if (revs->max_age != -1 && (commit->date < revs->max_age))
obj->flags |= UNINTERESTING; obj->flags |= UNINTERESTING;
if (add_parents_to_list(revs, commit, &list) < 0) if (add_parents_to_list(revs, commit, &list, NULL) < 0)
return -1; return -1;
if (obj->flags & UNINTERESTING) { if (obj->flags & UNINTERESTING) {
mark_parents_uninteresting(commit); mark_parents_uninteresting(commit);
@ -1458,10 +1474,12 @@ enum rewrite_result {
static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp) static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
{ {
struct commit_list *cache = NULL;
for (;;) { for (;;) {
struct commit *p = *pp; struct commit *p = *pp;
if (!revs->limited) if (!revs->limited)
if (add_parents_to_list(revs, p, &revs->commits) < 0) if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
return rewrite_one_error; return rewrite_one_error;
if (p->parents && p->parents->next) if (p->parents && p->parents->next)
return rewrite_one_ok; return rewrite_one_ok;
@ -1580,7 +1598,7 @@ static struct commit *get_revision_1(struct rev_info *revs)
if (revs->max_age != -1 && if (revs->max_age != -1 &&
(commit->date < revs->max_age)) (commit->date < revs->max_age))
continue; continue;
if (add_parents_to_list(revs, commit, &revs->commits) < 0) if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
return NULL; return NULL;
} }