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Merge branch 'jk/packfile-reuse-cleanup'

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The way "git pack-objects" reuses objects stored in existing pack
to generate its result has been improved.

* jk/packfile-reuse-cleanup:
  pack-bitmap: don't rely on bitmap_git->reuse_objects
  pack-objects: add checks for duplicate objects
  pack-objects: improve partial packfile reuse
  builtin/pack-objects: introduce obj_is_packed()
  pack-objects: introduce pack.allowPackReuse
  csum-file: introduce hashfile_total()
  pack-bitmap: simplify bitmap_has_oid_in_uninteresting()
  pack-bitmap: uninteresting oid can be outside bitmapped packfile
  pack-bitmap: introduce bitmap_walk_contains()
  ewah/bitmap: introduce bitmap_word_alloc()
  packfile: expose get_delta_base()
  builtin/pack-objects: report reused packfile objects
This commit is contained in:
Junio C Hamano
2020-02-14 12:54:19 -08:00
parent daef1b300b d2ea031046
commit a14aebeac3
9 changed files with 377 additions and 137 deletions
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261
builtin/pack-objects.c
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@ -92,10 +92,11 @@ static struct progress *progress_state;
static struct packed_git *reuse_packfile;
static uint32_t reuse_packfile_objects;
static off_t reuse_packfile_offset;
static struct bitmap *reuse_packfile_bitmap;
static int use_bitmap_index_default = 1;
static int use_bitmap_index = -1;
static int allow_pack_reuse = 1;
static enum {
WRITE_BITMAP_FALSE = 0,
WRITE_BITMAP_QUIET,
@ -784,57 +785,185 @@ static struct object_entry **compute_write_order(void)
return wo;
}
static off_t write_reused_pack(struct hashfile *f)
/*
* A reused set of objects. All objects in a chunk have the same
* relative position in the original packfile and the generated
* packfile.
*/
static struct reused_chunk {
/* The offset of the first object of this chunk in the original
* packfile. */
off_t original;
/* The offset of the first object of this chunk in the generated
* packfile minus "original". */
off_t difference;
} *reused_chunks;
static int reused_chunks_nr;
static int reused_chunks_alloc;
static void record_reused_object(off_t where, off_t offset)
{
unsigned char buffer[8192];
off_t to_write, total;
int fd;
if (reused_chunks_nr && reused_chunks[reused_chunks_nr-1].difference == offset)
return;
if (!is_pack_valid(reuse_packfile))
die(_("packfile is invalid: %s"), reuse_packfile->pack_name);
ALLOC_GROW(reused_chunks, reused_chunks_nr + 1,
reused_chunks_alloc);
reused_chunks[reused_chunks_nr].original = where;
reused_chunks[reused_chunks_nr].difference = offset;
reused_chunks_nr++;
}
fd = git_open(reuse_packfile->pack_name);
if (fd < 0)
die_errno(_("unable to open packfile for reuse: %s"),
reuse_packfile->pack_name);
if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
die_errno(_("unable to seek in reused packfile"));
if (reuse_packfile_offset < 0)
reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
while (to_write) {
int read_pack = xread(fd, buffer, sizeof(buffer));
if (read_pack <= 0)
die_errno(_("unable to read from reused packfile"));
if (read_pack > to_write)
read_pack = to_write;
hashwrite(f, buffer, read_pack);
to_write -= read_pack;
/*
* We don't know the actual number of objects written,
* only how many bytes written, how many bytes total, and
* how many objects total. So we can fake it by pretending all
* objects we are writing are the same size. This gives us a
* smooth progress meter, and at the end it matches the true
* answer.
*/
written = reuse_packfile_objects *
(((double)(total - to_write)) / total);
display_progress(progress_state, written);
/*
* Binary search to find the chunk that "where" is in. Note
* that we're not looking for an exact match, just the first
* chunk that contains it (which implicitly ends at the start
* of the next chunk.
*/
static off_t find_reused_offset(off_t where)
{
int lo = 0, hi = reused_chunks_nr;
while (lo < hi) {
int mi = lo + ((hi - lo) / 2);
if (where == reused_chunks[mi].original)
return reused_chunks[mi].difference;
if (where < reused_chunks[mi].original)
hi = mi;
else
lo = mi + 1;
}
close(fd);
written = reuse_packfile_objects;
display_progress(progress_state, written);
return reuse_packfile_offset - sizeof(struct pack_header);
/*
* The first chunk starts at zero, so we can't have gone below
* there.
*/
assert(lo);
return reused_chunks[lo-1].difference;
}
static void write_reused_pack_one(size_t pos, struct hashfile *out,
struct pack_window **w_curs)
{
off_t offset, next, cur;
enum object_type type;
unsigned long size;
offset = reuse_packfile->revindex[pos].offset;
next = reuse_packfile->revindex[pos + 1].offset;
record_reused_object(offset, offset - hashfile_total(out));
cur = offset;
type = unpack_object_header(reuse_packfile, w_curs, &cur, &size);
assert(type >= 0);
if (type == OBJ_OFS_DELTA) {
off_t base_offset;
off_t fixup;
unsigned char header[MAX_PACK_OBJECT_HEADER];
unsigned len;
base_offset = get_delta_base(reuse_packfile, w_curs, &cur, type, offset);
assert(base_offset != 0);
/* Convert to REF_DELTA if we must... */
if (!allow_ofs_delta) {
int base_pos = find_revindex_position(reuse_packfile, base_offset);
const unsigned char *base_sha1 =
nth_packed_object_sha1(reuse_packfile,
reuse_packfile->revindex[base_pos].nr);
len = encode_in_pack_object_header(header, sizeof(header),
OBJ_REF_DELTA, size);
hashwrite(out, header, len);
hashwrite(out, base_sha1, 20);
copy_pack_data(out, reuse_packfile, w_curs, cur, next - cur);
return;
}
/* Otherwise see if we need to rewrite the offset... */
fixup = find_reused_offset(offset) -
find_reused_offset(base_offset);
if (fixup) {
unsigned char ofs_header[10];
unsigned i, ofs_len;
off_t ofs = offset - base_offset - fixup;
len = encode_in_pack_object_header(header, sizeof(header),
OBJ_OFS_DELTA, size);
i = sizeof(ofs_header) - 1;
ofs_header[i] = ofs & 127;
while (ofs >>= 7)
ofs_header[--i] = 128 | (--ofs & 127);
ofs_len = sizeof(ofs_header) - i;
hashwrite(out, header, len);
hashwrite(out, ofs_header + sizeof(ofs_header) - ofs_len, ofs_len);
copy_pack_data(out, reuse_packfile, w_curs, cur, next - cur);
return;
}
/* ...otherwise we have no fixup, and can write it verbatim */
}
copy_pack_data(out, reuse_packfile, w_curs, offset, next - offset);
}
static size_t write_reused_pack_verbatim(struct hashfile *out,
struct pack_window **w_curs)
{
size_t pos = 0;
while (pos < reuse_packfile_bitmap->word_alloc &&
reuse_packfile_bitmap->words[pos] == (eword_t)~0)
pos++;
if (pos) {
off_t to_write;
written = (pos * BITS_IN_EWORD);
to_write = reuse_packfile->revindex[written].offset
- sizeof(struct pack_header);
/* We're recording one chunk, not one object. */
record_reused_object(sizeof(struct pack_header), 0);
hashflush(out);
copy_pack_data(out, reuse_packfile, w_curs,
sizeof(struct pack_header), to_write);
display_progress(progress_state, written);
}
return pos;
}
static void write_reused_pack(struct hashfile *f)
{
size_t i = 0;
uint32_t offset;
struct pack_window *w_curs = NULL;
if (allow_ofs_delta)
i = write_reused_pack_verbatim(f, &w_curs);
for (; i < reuse_packfile_bitmap->word_alloc; ++i) {
eword_t word = reuse_packfile_bitmap->words[i];
size_t pos = (i * BITS_IN_EWORD);
for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
if ((word >> offset) == 0)
break;
offset += ewah_bit_ctz64(word >> offset);
write_reused_pack_one(pos + offset, f, &w_curs);
display_progress(progress_state, ++written);
}
}
unuse_pack(&w_curs);
}
static const char no_split_warning[] = N_(
@ -867,11 +996,9 @@ static void write_pack_file(void)
offset = write_pack_header(f, nr_remaining);
if (reuse_packfile) {
off_t packfile_size;
assert(pack_to_stdout);
packfile_size = write_reused_pack(f);
offset += packfile_size;
write_reused_pack(f);
offset = hashfile_total(f);
}
nr_written = 0;
@ -1000,6 +1127,10 @@ static int have_duplicate_entry(const struct object_id *oid,
{
struct object_entry *entry;
if (reuse_packfile_bitmap &&
bitmap_walk_contains(bitmap_git, reuse_packfile_bitmap, oid))
return 1;
entry = packlist_find(&to_pack, oid);
if (!entry)
return 0;
@ -2552,6 +2683,13 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
free(p);
}
static int obj_is_packed(const struct object_id *oid)
{
return packlist_find(&to_pack, oid) ||
(reuse_packfile_bitmap &&
bitmap_walk_contains(bitmap_git, reuse_packfile_bitmap, oid));
}
static void add_tag_chain(const struct object_id *oid)
{
struct tag *tag;
@ -2563,7 +2701,7 @@ static void add_tag_chain(const struct object_id *oid)
* it was included via bitmaps, we would not have parsed it
* previously).
*/
if (packlist_find(&to_pack, oid))
if (obj_is_packed(oid))
return;
tag = lookup_tag(the_repository, oid);
@ -2587,7 +2725,7 @@ static int add_ref_tag(const char *path, const struct object_id *oid, int flag,
if (starts_with(path, "refs/tags/") && /* is a tag? */
!peel_ref(path, &peeled) && /* peelable? */
packlist_find(&to_pack, &peeled)) /* object packed? */
obj_is_packed(&peeled)) /* object packed? */
add_tag_chain(oid);
return 0;
}
@ -2655,6 +2793,7 @@ static void prepare_pack(int window, int depth)
if (nr_deltas && n > 1) {
unsigned nr_done = 0;
if (progress)
progress_state = start_progress(_("Compressing objects"),
nr_deltas);
@ -2699,6 +2838,10 @@ static int git_pack_config(const char *k, const char *v, void *cb)
use_bitmap_index_default = git_config_bool(k, v);
return 0;
}
if (!strcmp(k, "pack.allowpackreuse")) {
allow_pack_reuse = git_config_bool(k, v);
return 0;
}
if (!strcmp(k, "pack.threads")) {
delta_search_threads = git_config_int(k, v);
if (delta_search_threads < 0)
@ -3030,8 +3173,8 @@ static void loosen_unused_packed_objects(void)
*/
static int pack_options_allow_reuse(void)
{
return pack_to_stdout &&
allow_ofs_delta &&
return allow_pack_reuse &&
pack_to_stdout &&
!ignore_packed_keep_on_disk &&
!ignore_packed_keep_in_core &&
(!local || !have_non_local_packs) &&
@ -3048,7 +3191,7 @@ static int get_object_list_from_bitmap(struct rev_info *revs)
bitmap_git,
&reuse_packfile,
&reuse_packfile_objects,
&reuse_packfile_offset)) {
&reuse_packfile_bitmap)) {
assert(reuse_packfile_objects);
nr_result += reuse_packfile_objects;
display_progress(progress_state, nr_result);
@ -3509,7 +3652,9 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
if (progress)
fprintf_ln(stderr,
_("Total %"PRIu32" (delta %"PRIu32"),"
" reused %"PRIu32" (delta %"PRIu32")"),
written, written_delta, reused, reused_delta);
" reused %"PRIu32" (delta %"PRIu32"),"
" pack-reused %"PRIu32),
written, written_delta, reused, reused_delta,
reuse_packfile_objects);
return 0;
}