diff options
| -rw-r--r-- | midx.c | 128 | ||||
| -rw-r--r-- | packfile.c | 17 | ||||
| -rw-r--r-- | packfile.h | 2 |
3 files changed, 147 insertions, 0 deletions
@@ -4,6 +4,7 @@ #include "lockfile.h" #include "packfile.h" #include "object-store.h" +#include "packfile.h" #include "midx.h" #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */ @@ -182,12 +183,21 @@ static void add_pack_to_midx(const char *full_path, size_t full_path_len, packs->list[packs->nr] = add_packed_git(full_path, full_path_len, 0); + if (!packs->list[packs->nr]) { warning(_("failed to add packfile '%s'"), full_path); return; } + if (open_pack_index(packs->list[packs->nr])) { + warning(_("failed to open pack-index '%s'"), + full_path); + close_pack(packs->list[packs->nr]); + FREE_AND_NULL(packs->list[packs->nr]); + return; + } + packs->names[packs->nr] = xstrdup(file_name); packs->pack_name_concat_len += strlen(file_name) + 1; packs->nr++; @@ -228,6 +238,119 @@ static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *p free(pairs); } +struct pack_midx_entry { + struct object_id oid; + uint32_t pack_int_id; + time_t pack_mtime; + uint64_t offset; +}; + +static int midx_oid_compare(const void *_a, const void *_b) +{ + const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a; + const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b; + int cmp = oidcmp(&a->oid, &b->oid); + + if (cmp) + return cmp; + + if (a->pack_mtime > b->pack_mtime) + return -1; + else if (a->pack_mtime < b->pack_mtime) + return 1; + + return a->pack_int_id - b->pack_int_id; +} + +static void fill_pack_entry(uint32_t pack_int_id, + struct packed_git *p, + uint32_t cur_object, + struct pack_midx_entry *entry) +{ + if (!nth_packed_object_oid(&entry->oid, p, cur_object)) + die(_("failed to locate object %d in packfile"), cur_object); + + entry->pack_int_id = pack_int_id; + entry->pack_mtime = p->mtime; + + entry->offset = nth_packed_object_offset(p, cur_object); +} + +/* + * It is possible to artificially get into a state where there are many + * duplicate copies of objects. That can create high memory pressure if + * we are to create a list of all objects before de-duplication. To reduce + * this memory pressure without a significant performance drop, automatically + * group objects by the first byte of their object id. Use the IDX fanout + * tables to group the data, copy to a local array, then sort. + * + * Copy only the de-duplicated entries (selected by most-recent modified time + * of a packfile containing the object). + */ +static struct pack_midx_entry *get_sorted_entries(struct packed_git **p, + uint32_t *perm, + uint32_t nr_packs, + uint32_t *nr_objects) +{ + uint32_t cur_fanout, cur_pack, cur_object; + uint32_t alloc_fanout, alloc_objects, total_objects = 0; + struct pack_midx_entry *entries_by_fanout = NULL; + struct pack_midx_entry *deduplicated_entries = NULL; + + for (cur_pack = 0; cur_pack < nr_packs; cur_pack++) + total_objects += p[cur_pack]->num_objects; + + /* + * As we de-duplicate by fanout value, we expect the fanout + * slices to be evenly distributed, with some noise. Hence, + * allocate slightly more than one 256th. + */ + alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16; + + ALLOC_ARRAY(entries_by_fanout, alloc_fanout); + ALLOC_ARRAY(deduplicated_entries, alloc_objects); + *nr_objects = 0; + + for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) { + uint32_t nr_fanout = 0; + + for (cur_pack = 0; cur_pack < nr_packs; cur_pack++) { + uint32_t start = 0, end; + + if (cur_fanout) + start = get_pack_fanout(p[cur_pack], cur_fanout - 1); + end = get_pack_fanout(p[cur_pack], cur_fanout); + + for (cur_object = start; cur_object < end; cur_object++) { + ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout); + fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]); + nr_fanout++; + } + } + + QSORT(entries_by_fanout, nr_fanout, midx_oid_compare); + + /* + * The batch is now sorted by OID and then mtime (descending). + * Take only the first duplicate. + */ + for (cur_object = 0; cur_object < nr_fanout; cur_object++) { + if (cur_object && !oidcmp(&entries_by_fanout[cur_object - 1].oid, + &entries_by_fanout[cur_object].oid)) + continue; + + ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects); + memcpy(&deduplicated_entries[*nr_objects], + &entries_by_fanout[cur_object], + sizeof(struct pack_midx_entry)); + (*nr_objects)++; + } + } + + free(entries_by_fanout); + return deduplicated_entries; +} + static size_t write_midx_pack_names(struct hashfile *f, char **pack_names, uint32_t num_packs) @@ -271,6 +394,8 @@ int write_midx_file(const char *object_dir) uint64_t written = 0; uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1]; uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1]; + uint32_t nr_entries; + struct pack_midx_entry *entries = NULL; midx_name = get_midx_filename(object_dir); if (safe_create_leading_directories(midx_name)) { @@ -296,6 +421,8 @@ int write_midx_file(const char *object_dir) ALLOC_ARRAY(pack_perm, packs.nr); sort_packs_by_name(packs.names, packs.nr, pack_perm); + entries = get_sorted_entries(packs.list, pack_perm, packs.nr, &nr_entries); + hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR); f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf); FREE_AND_NULL(midx_name); @@ -365,5 +492,6 @@ int write_midx_file(const char *object_dir) free(packs.list); free(packs.names); + free(entries); return 0; } diff --git a/packfile.c b/packfile.c index ee1ab9b804..3d652212c6 100644 --- a/packfile.c +++ b/packfile.c @@ -196,6 +196,23 @@ int open_pack_index(struct packed_git *p) return ret; } +uint32_t get_pack_fanout(struct packed_git *p, uint32_t value) +{ + const uint32_t *level1_ofs = p->index_data; + + if (!level1_ofs) { + if (open_pack_index(p)) + return 0; + level1_ofs = p->index_data; + } + + if (p->index_version > 1) { + level1_ofs += 2; + } + + return ntohl(level1_ofs[value]); +} + static struct packed_git *alloc_packed_git(int extra) { struct packed_git *p = xmalloc(st_add(sizeof(*p), extra)); diff --git a/packfile.h b/packfile.h index d2ad30300a..b0eed44c0b 100644 --- a/packfile.h +++ b/packfile.h @@ -69,6 +69,8 @@ extern int open_pack_index(struct packed_git *); */ extern void close_pack_index(struct packed_git *); +extern uint32_t get_pack_fanout(struct packed_git *p, uint32_t value); + extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t, unsigned long *); extern void close_pack_windows(struct packed_git *); extern void close_pack(struct packed_git *); |