Revert "name-rev: release unused name strings"

This reverts commit 2d53975488.

3656f84278 (name-rev: prefer shorter names over following merges,
2021-12-04) broke the assumption of 2d53975488 (name-rev: release unused
name strings, 2020-02-04) that a better name for a child is a better
name for all of its ancestors as well, because it added a penalty for
generation > 0.  This leads to strings being free(3)'d that are still
needed.

079f970971 (name-rev: sort tip names before applying, 2020-02-05)
already reduced the number of free(3) calls for the use case that
motivated the original patch (name-rev --all in the Chromium repository)
from ca. 44000 to 5, and 3656f84278 eliminated even those few.  So this
revert won't affect name-rev's performance on that particular repo.

Reported-by: Thomas Hurst <tom@hur.st>
Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
René Scharfe 2022-04-22 20:44:40 +02:00 committed by Junio C Hamano
parent 3656f84278
commit 45a14f578e

View file

@ -17,7 +17,7 @@
#define CUTOFF_DATE_SLOP 86400 #define CUTOFF_DATE_SLOP 86400
struct rev_name { struct rev_name {
char *tip_name; const char *tip_name;
timestamp_t taggerdate; timestamp_t taggerdate;
int generation; int generation;
int distance; int distance;
@ -34,7 +34,7 @@ static struct commit_rev_name rev_names;
static int is_valid_rev_name(const struct rev_name *name) static int is_valid_rev_name(const struct rev_name *name)
{ {
return name && (name->generation || name->tip_name); return name && name->tip_name;
} }
static struct rev_name *get_commit_rev_name(const struct commit *commit) static struct rev_name *get_commit_rev_name(const struct commit *commit)
@ -96,21 +96,10 @@ static struct rev_name *create_or_update_name(struct commit *commit,
{ {
struct rev_name *name = commit_rev_name_at(&rev_names, commit); struct rev_name *name = commit_rev_name_at(&rev_names, commit);
if (is_valid_rev_name(name)) { if (is_valid_rev_name(name) &&
if (!is_better_name(name, taggerdate, generation, distance, from_tag)) !is_better_name(name, taggerdate, generation, distance, from_tag))
return NULL; return NULL;
/*
* This string might still be shared with ancestors
* (generation > 0). We can release it here regardless,
* because the new name that has just won will be better
* for them as well, so name_rev() will replace these
* stale pointers when it processes the parents.
*/
if (!name->generation)
free(name->tip_name);
}
name->taggerdate = taggerdate; name->taggerdate = taggerdate;
name->generation = generation; name->generation = generation;
name->distance = distance; name->distance = distance;