From: Sun Chao <sunchao9@xxxxxxxxxx>
When calling `git pack-redundant --all`, if there are too many local
packs and too many redundant objects within them, the too deep iteration
of `get_permutations` will exhaust all the resources, and the process of
`git pack-redundant` will be killed.
The following script could create a repository with too many redundant
packs, and running `git pack-redundant --all` in the `test.git` repo
will die soon.
#!/bin/sh
repo="$(pwd)/test.git"
work="$(pwd)/test"
i=1
max=199
if test -d "$repo" || test -d "$work"; then
echo >&2 "ERROR: '$repo' or '$work' already exist"
exit 1
fi
git init -q --bare "$repo"
git --git-dir="$repo" config gc.auto 0
git --git-dir="$repo" config transfer.unpackLimit 0
git clone -q "$repo" "$work" 2>/dev/null
while :; do
cd "$work"
echo "loop $i: $(date +%s)" >$i
git add $i
git commit -q -sm "loop $i"
git push -q origin HEAD:master
printf "\rCreate pack %4d/%d\t" $i $max
if test $i -ge $max; then break; fi
cd "$repo"
git repack -q
if test $(($i % 2)) -eq 0; then
git repack -aq
pack=$(ls -t $repo/objects/pack/*.pack | head -1)
touch "${pack%.pack}.keep"
fi
i=$((i+1))
done
printf "\ndone\n"
To get the `min` unique pack list, we can replace the iteration in
`minimize` function with a new algorithm, and this could solve this
issue:
1. Get the unique and non_uniqe packs, add the unique packs to the
`min` list.
2. Remove the objects of unique packs from non_unique packs, then each
object left in the non_unique packs will have at least two copies.
3. Sort the non_unique packs by the objects' size, more objects first,
and add the first non_unique pack to `min` list.
4. Drop the duplicated objects from other packs in the ordered
non_unique pack list, and repeat step 3.
Original PR and discussions: https://github.com/jiangxin/git/pull/25
Signed-off-by: Sun Chao <sunchao9@xxxxxxxxxx>
Signed-off-by: Jiang Xin <worldhello.net@xxxxxxxxx>
---
builtin/pack-redundant.c | 109 ++++++++++++++++++++++++---------------
1 file changed, 68 insertions(+), 41 deletions(-)
diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c
index cf9a9aabd4..3655cc7dc6 100644
--- a/builtin/pack-redundant.c
+++ b/builtin/pack-redundant.c
@@ -421,14 +421,52 @@ static inline off_t pack_set_bytecount(struct pack_list *pl)
return ret;
}
+static int cmp_pack_list_reverse(const void *a, const void *b)
+{
+ struct pack_list *pl_a = *((struct pack_list **)a);
+ struct pack_list *pl_b = *((struct pack_list **)b);
+ size_t sz_a = pl_a->all_objects->size;
+ size_t sz_b = pl_b->all_objects->size;
+
+ if (sz_a == sz_b)
+ return 0;
+ else if (sz_a < sz_b)
+ return 1;
+ else
+ return -1;
+}
+
+/* Sort pack_list, greater size of all_objects first */
+static void sort_pack_list(struct pack_list **pl)
+{
+ struct pack_list **ary, *p;
+ int i;
+ size_t n = pack_list_size(*pl);
+
+ if (n < 2)
+ return;
+
+ /* prepare an array of packed_list for easier sorting */
+ ary = xcalloc(n, sizeof(struct pack_list *));
+ for (n = 0, p = *pl; p; p = p->next)
+ ary[n++] = p;
+
+ QSORT(ary, n, cmp_pack_list_reverse);
+
+ /* link them back again */
+ for (i = 0; i < n - 1; i++)
+ ary[i]->next = ary[i + 1];
+ ary[n - 1]->next = NULL;
+ *pl = ary[0];
+
+ free(ary);
+}
+
+
static void minimize(struct pack_list **min)
{
- struct pack_list *pl, *unique = NULL,
- *non_unique = NULL, *min_perm = NULL;
- struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
- struct llist *missing;
- off_t min_perm_size = 0, perm_size;
- int n;
+ struct pack_list *pl, *unique = NULL, *non_unique = NULL;
+ struct llist *missing, *unique_pack_objects;
pl = local_packs;
while (pl) {
@@ -446,49 +484,37 @@ static void minimize(struct pack_list **min)
pl = pl->next;
}
+ *min = unique;
+
/* return if there are no objects missing from the unique set */
if (missing->size == 0) {
- *min = unique;
free(missing);
return;
}
- /* find the permutations which contain all missing objects */
- for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) {
- perm_all = perm = get_permutations(non_unique, n);
- while (perm) {
- if (is_superset(perm->pl, missing)) {
- new_perm = xmalloc(sizeof(struct pll));
- memcpy(new_perm, perm, sizeof(struct pll));
- new_perm->next = perm_ok;
- perm_ok = new_perm;
- }
- perm = perm->next;
- }
- if (perm_ok)
- break;
- pll_free(perm_all);
- }
- if (perm_ok == NULL)
- die("Internal error: No complete sets found!");
-
- /* find the permutation with the smallest size */
- perm = perm_ok;
- while (perm) {
- perm_size = pack_set_bytecount(perm->pl);
- if (!min_perm_size || min_perm_size > perm_size) {
- min_perm_size = perm_size;
- min_perm = perm->pl;
- }
- perm = perm->next;
- }
- *min = min_perm;
- /* add the unique packs to the list */
- pl = unique;
+ unique_pack_objects = llist_copy(all_objects);
+ llist_sorted_difference_inplace(unique_pack_objects, missing);
+
+ /* remove unique pack objects from the non_unique packs */
+ pl = non_unique;
while (pl) {
- pack_list_insert(min, pl);
+ llist_sorted_difference_inplace(pl->all_objects, unique_pack_objects);
pl = pl->next;
}
+
+ while (non_unique) {
+ /* sort the non_unique packs, greater size of all_objects first */
+ sort_pack_list(&non_unique);
+ if (non_unique->all_objects->size == 0)
+ break;
+
+ pack_list_insert(min, non_unique);
+
+ for (pl = non_unique->next; pl && pl->all_objects->size > 0; pl = pl->next)
+ llist_sorted_difference_inplace(pl->all_objects, non_unique->all_objects);
+
+ non_unique = non_unique->next;
+ }
}
static void load_all_objects(void)
@@ -603,7 +629,7 @@ static void load_all(void)
int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
{
int i;
- struct pack_list *min, *red, *pl;
+ struct pack_list *min = NULL, *red, *pl;
struct llist *ignore;
struct object_id *oid;
char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \n + \0 */
@@ -664,6 +690,7 @@ int cmd_pack_redundant(int argc, const char **argv, const char *prefix)
pl = local_packs;
while (pl) {
llist_sorted_difference_inplace(pl->unique_objects, ignore);
+ llist_sorted_difference_inplace(pl->all_objects, ignore);
pl = pl->next;
}
--
2.20.0.3.gc45e608566
