Instead of using 8 bytes (on 64 bit arch) to store a pointer to a
pack. Use an index isntead since the number of packs should be
relatively small.
This limits the number of packs we can handle to 256 (still
unreasonably high for a repo to work well). If you have more than 256
packs, you'll need an older version of Git to repack first.
This technically saves 7 bytes. But we don't see any of that in
practice due to padding. The saving becomes real when we pack this
struct tighter later.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclo...@gmail.com>
---
builtin/pack-objects.c | 48 ++++++++++++++++++++++++++++++++----------
pack-objects.h | 12 +++++++++--
2 files changed, 47 insertions(+), 13 deletions(-)
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 7bb5544883..d0d371714a 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -367,7 +367,7 @@ static unsigned long write_no_reuse_object(struct hashfile
*f, struct object_ent
static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
unsigned long limit, int usable_delta)
{
- struct packed_git *p = entry->in_pack;
+ struct packed_git *p = IN_PACK(&to_pack, entry);
struct pack_window *w_curs = NULL;
struct revindex_entry *revidx;
off_t offset;
@@ -478,7 +478,7 @@ static off_t write_object(struct hashfile *f,
if (!reuse_object)
to_reuse = 0; /* explicit */
- else if (!entry->in_pack)
+ else if (!IN_PACK(&to_pack, entry))
to_reuse = 0; /* can't reuse what we don't have */
else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
/* check_object() decided it for us ... */
@@ -1074,7 +1074,15 @@ static void create_object_entry(const struct object_id
*oid,
else
nr_result++;
if (found_pack) {
- entry->in_pack = found_pack;
+ int i;
+
+ for (i = 0; i < (1 << OE_IN_PACK_BITS); i++)
+ if (to_pack.in_pack[i] == found_pack) {
+ entry->in_pack_idx = i;
+ break;
+ }
+ if (i == (1 << OE_IN_PACK_BITS))
+ die("BUG: pack not found!");
entry->in_pack_offset = found_offset;
}
@@ -1399,8 +1407,8 @@ static void cleanup_preferred_base(void)
static void check_object(struct object_entry *entry)
{
- if (entry->in_pack) {
- struct packed_git *p = entry->in_pack;
+ if (IN_PACK(&to_pack, entry)) {
+ struct packed_git *p = IN_PACK(&to_pack, entry);
struct pack_window *w_curs = NULL;
const unsigned char *base_ref = NULL;
struct object_entry *base_entry;
@@ -1535,14 +1543,16 @@ static int pack_offset_sort(const void *_a, const void
*_b)
{
const struct object_entry *a = *(struct object_entry **)_a;
const struct object_entry *b = *(struct object_entry **)_b;
+ const struct packed_git *a_in_pack = IN_PACK(&to_pack, a);
+ const struct packed_git *b_in_pack = IN_PACK(&to_pack, b);
/* avoid filesystem trashing with loose objects */
- if (!a->in_pack && !b->in_pack)
+ if (!a_in_pack && !b_in_pack)
return oidcmp(&a->idx.oid, &b->idx.oid);
- if (a->in_pack < b->in_pack)
+ if (a_in_pack < b_in_pack)
return -1;
- if (a->in_pack > b->in_pack)
+ if (a_in_pack > b_in_pack)
return 1;
return a->in_pack_offset < b->in_pack_offset ? -1 :
(a->in_pack_offset > b->in_pack_offset);
@@ -1578,7 +1588,7 @@ static void drop_reused_delta(struct object_entry *entry)
oi.sizep = &entry->size;
oi.typep = &type;
- if (packed_object_info(entry->in_pack, entry->in_pack_offset, &oi) < 0)
{
+ if (packed_object_info(IN_PACK(&to_pack, entry), entry->in_pack_offset,
&oi) < 0) {
/*
* We failed to get the info from this pack for some reason;
* fall back to sha1_object_info, which may find another copy.
@@ -1848,8 +1858,8 @@ static int try_delta(struct unpacked *trg, struct
unpacked *src,
* it, we will still save the transfer cost, as we already know
* the other side has it and we won't send src_entry at all.
*/
- if (reuse_delta && trg_entry->in_pack &&
- trg_entry->in_pack == src_entry->in_pack &&
+ if (reuse_delta && IN_PACK(&to_pack, trg_entry) &&
+ IN_PACK(&to_pack, trg_entry) == IN_PACK(&to_pack, src_entry) &&
!src_entry->preferred_base &&
trg_entry->in_pack_type != OBJ_REF_DELTA &&
trg_entry->in_pack_type != OBJ_OFS_DELTA)
@@ -2958,6 +2968,21 @@ static int option_parse_unpack_unreachable(const struct
option *opt,
return 0;
}
+static void init_in_pack_mapping(struct packing_data *to_pack)
+{
+ struct packed_git *p;
+ int i = 0;
+
+ /* let IN_PACK() return NULL if in_pack_idx is zero */
+ to_pack->in_pack[i++] = NULL;
+
+ for (p = packed_git; p; p = p->next, i++) {
+ if (i >= (1 << OE_IN_PACK_BITS))
+ die("BUG: too many packs to handle!");
+ to_pack->in_pack[i] = p;
+ }
+}
+
int cmd_pack_objects(int argc, const char **argv, const char *prefix)
{
int use_internal_rev_list = 0;
@@ -3190,6 +3215,7 @@ int cmd_pack_objects(int argc, const char **argv, const
char *prefix)
}
}
}
+ init_in_pack_mapping(&to_pack);
if (progress)
progress_state = start_progress(_("Counting objects"), 0);
diff --git a/pack-objects.h b/pack-objects.h
index 3bef28196c..839d5dc4fd 100644
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -3,10 +3,14 @@
#define OE_DFS_STATE_BITS 2
#define OE_DEPTH_BITS 12
+#define OE_IN_PACK_BITS 8
#define IN_PACK_POS(to_pack, obj) \
(to_pack)->in_pack_pos[(struct object_entry *)(obj) -
(to_pack)->objects]
+#define IN_PACK(to_pack, obj) \
+ (to_pack)->in_pack[(obj)->in_pack_idx]
+
/*
* State flags for depth-first search used for analyzing delta cycles.
*
@@ -23,7 +27,6 @@ enum dfs_state {
struct object_entry {
struct pack_idx_entry idx;
unsigned long size; /* uncompressed size */
- struct packed_git *in_pack; /* already in pack */
off_t in_pack_offset;
struct object_entry *delta; /* delta base object */
struct object_entry *delta_child; /* deltified objects who bases me */
@@ -35,6 +38,7 @@ struct object_entry {
unsigned long z_delta_size; /* delta data size (compressed) */
uint32_t hash; /* name hint hash */
unsigned char in_pack_header_size; /* note: spare bits available! */
+ unsigned in_pack_idx:OE_IN_PACK_BITS; /* already in pack */
unsigned type:TYPE_BITS;
unsigned in_pack_type:TYPE_BITS; /* could be delta */
unsigned preferred_base:1; /*
@@ -46,9 +50,12 @@ struct object_entry {
unsigned tagged:1; /* near the very tip of refs */
unsigned filled:1; /* assigned write-order */
unsigned dfs_state:OE_DFS_STATE_BITS;
+
+ /* XXX 12 bits hole, try to pack */
+
unsigned depth:OE_DEPTH_BITS;
- /* size: 112 */
+ /* size: 112, padding: 4 */
};
struct packing_data {
@@ -59,6 +66,7 @@ struct packing_data {
uint32_t index_size;
unsigned int *in_pack_pos;
+ struct packed_git *in_pack[1 << OE_IN_PACK_BITS];
};
struct object_entry *packlist_alloc(struct packing_data *pdata,
--
2.16.1.435.g8f24da2e1a
