pack-bitmap-write.c

   1 #include "cache.h"
   2 #include "object-store.h"
   3 #include "commit.h"
   4 #include "tag.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "list-objects.h"
   8 #include "progress.h"
   9 #include "pack-revindex.h"
  10 #include "pack.h"
  11 #include "pack-bitmap.h"
  12 #include "sha1-lookup.h"
  13 #include "pack-objects.h"
  14
  15 struct bitmapped_commit {
  16         struct commit *commit;
  17         struct ewah_bitmap *bitmap;
  18         struct ewah_bitmap *write_as;
  19         int flags;
  20         int xor_offset;
  21         uint32_t commit_pos;
  22 };
  23
  24 struct bitmap_writer {
  25         struct ewah_bitmap *commits;
  26         struct ewah_bitmap *trees;
  27         struct ewah_bitmap *blobs;
  28         struct ewah_bitmap *tags;
  29
  30         khash_sha1 *bitmaps;
  31         khash_sha1 *reused;
  32         struct packing_data *to_pack;
  33
  34         struct bitmapped_commit *selected;
  35         unsigned int selected_nr, selected_alloc;
  36
  37         struct progress *progress;
  38         int show_progress;
  39         unsigned char pack_checksum[20];
  40 };
  41
  42 static struct bitmap_writer writer;
  43
  44 void bitmap_writer_show_progress(int show)
  45 {
  46         writer.show_progress = show;
  47 }
  48
  49 /**
  50  * Build the initial type index for the packfile
  51  */
  52 void bitmap_writer_build_type_index(struct pack_idx_entry **index,
  53                                     uint32_t index_nr)
  54 {
  55         uint32_t i;
  56
  57         writer.commits = ewah_new();
  58         writer.trees = ewah_new();
  59         writer.blobs = ewah_new();
  60         writer.tags = ewah_new();
  61
  62         for (i = 0; i < index_nr; ++i) {
  63                 struct object_entry *entry = (struct object_entry *)index[i];
  64                 enum object_type real_type;
  65
  66                 entry->in_pack_pos = i;
  67
  68                 switch (entry->type) {
  69                 case OBJ_COMMIT:
  70                 case OBJ_TREE:
  71                 case OBJ_BLOB:
  72                 case OBJ_TAG:
  73                         real_type = entry->type;
  74                         break;
  75
  76                 default:
  77                         real_type = oid_object_info(the_repository,
  78                                                     &entry->idx.oid, NULL);
  79                         break;
  80                 }
  81
  82                 switch (real_type) {
  83                 case OBJ_COMMIT:
  84                         ewah_set(writer.commits, i);
  85                         break;
  86
  87                 case OBJ_TREE:
  88                         ewah_set(writer.trees, i);
  89                         break;
  90
  91                 case OBJ_BLOB:
  92                         ewah_set(writer.blobs, i);
  93                         break;
  94
  95                 case OBJ_TAG:
  96                         ewah_set(writer.tags, i);
  97                         break;
  98
  99                 default:
 100                         die("Missing type information for %s (%d/%d)",
 101                             oid_to_hex(&entry->idx.oid), real_type,
 102                             entry->type);
 103                 }
 104         }
 105 }
 106
 107 /**
 108  * Compute the actual bitmaps
 109  */
 110 static struct object **seen_objects;
 111 static unsigned int seen_objects_nr, seen_objects_alloc;
 112
 113 static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
 114 {
 115         if (writer.selected_nr >= writer.selected_alloc) {
 116                 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
 117                 REALLOC_ARRAY(writer.selected, writer.selected_alloc);
 118         }
 119
 120         writer.selected[writer.selected_nr].commit = commit;
 121         writer.selected[writer.selected_nr].bitmap = reused;
 122         writer.selected[writer.selected_nr].flags = 0;
 123
 124         writer.selected_nr++;
 125 }
 126
 127 static inline void mark_as_seen(struct object *object)
 128 {
 129         ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
 130         seen_objects[seen_objects_nr++] = object;
 131 }
 132
 133 static inline void reset_all_seen(void)
 134 {
 135         unsigned int i;
 136         for (i = 0; i < seen_objects_nr; ++i) {
 137                 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
 138         }
 139         seen_objects_nr = 0;
 140 }
 141
 142 static uint32_t find_object_pos(const unsigned char *sha1)
 143 {
 144         struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
 145
 146         if (!entry) {
 147                 die("Failed to write bitmap index. Packfile doesn't have full closure "
 148                         "(object %s is missing)", sha1_to_hex(sha1));
 149         }
 150
 151         return entry->in_pack_pos;
 152 }
 153
 154 static void show_object(struct object *object, const char *name, void *data)
 155 {
 156         struct bitmap *base = data;
 157         bitmap_set(base, find_object_pos(object->oid.hash));
 158         mark_as_seen(object);
 159 }
 160
 161 static void show_commit(struct commit *commit, void *data)
 162 {
 163         mark_as_seen((struct object *)commit);
 164 }
 165
 166 static int
 167 add_to_include_set(struct bitmap *base, struct commit *commit)
 168 {
 169         khiter_t hash_pos;
 170         uint32_t bitmap_pos = find_object_pos(commit->object.oid.hash);
 171
 172         if (bitmap_get(base, bitmap_pos))
 173                 return 0;
 174
 175         hash_pos = kh_get_sha1(writer.bitmaps, commit->object.oid.hash);
 176         if (hash_pos < kh_end(writer.bitmaps)) {
 177                 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
 178                 bitmap_or_ewah(base, bc->bitmap);
 179                 return 0;
 180         }
 181
 182         bitmap_set(base, bitmap_pos);
 183         return 1;
 184 }
 185
 186 static int
 187 should_include(struct commit *commit, void *_data)
 188 {
 189         struct bitmap *base = _data;
 190
 191         if (!add_to_include_set(base, commit)) {
 192                 struct commit_list *parent = commit->parents;
 193
 194                 mark_as_seen((struct object *)commit);
 195
 196                 while (parent) {
 197                         parent->item->object.flags |= SEEN;
 198                         mark_as_seen((struct object *)parent->item);
 199                         parent = parent->next;
 200                 }
 201
 202                 return 0;
 203         }
 204
 205         return 1;
 206 }
 207
 208 static void compute_xor_offsets(void)
 209 {
 210         static const int MAX_XOR_OFFSET_SEARCH = 10;
 211
 212         int i, next = 0;
 213
 214         while (next < writer.selected_nr) {
 215                 struct bitmapped_commit *stored = &writer.selected[next];
 216
 217                 int best_offset = 0;
 218                 struct ewah_bitmap *best_bitmap = stored->bitmap;
 219                 struct ewah_bitmap *test_xor;
 220
 221                 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
 222                         int curr = next - i;
 223
 224                         if (curr < 0)
 225                                 break;
 226
 227                         test_xor = ewah_pool_new();
 228                         ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
 229
 230                         if (test_xor->buffer_size < best_bitmap->buffer_size) {
 231                                 if (best_bitmap != stored->bitmap)
 232                                         ewah_pool_free(best_bitmap);
 233
 234                                 best_bitmap = test_xor;
 235                                 best_offset = i;
 236                         } else {
 237                                 ewah_pool_free(test_xor);
 238                         }
 239                 }
 240
 241                 stored->xor_offset = best_offset;
 242                 stored->write_as = best_bitmap;
 243
 244                 next++;
 245         }
 246 }
 247
 248 void bitmap_writer_build(struct packing_data *to_pack)
 249 {
 250         static const double REUSE_BITMAP_THRESHOLD = 0.2;
 251
 252         int i, reuse_after, need_reset;
 253         struct bitmap *base = bitmap_new();
 254         struct rev_info revs;
 255
 256         writer.bitmaps = kh_init_sha1();
 257         writer.to_pack = to_pack;
 258
 259         if (writer.show_progress)
 260                 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
 261
 262         init_revisions(&revs, NULL);
 263         revs.tag_objects = 1;
 264         revs.tree_objects = 1;
 265         revs.blob_objects = 1;
 266         revs.no_walk = 0;
 267
 268         revs.include_check = should_include;
 269         reset_revision_walk();
 270
 271         reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
 272         need_reset = 0;
 273
 274         for (i = writer.selected_nr - 1; i >= 0; --i) {
 275                 struct bitmapped_commit *stored;
 276                 struct object *object;
 277
 278                 khiter_t hash_pos;
 279                 int hash_ret;
 280
 281                 stored = &writer.selected[i];
 282                 object = (struct object *)stored->commit;
 283
 284                 if (stored->bitmap == NULL) {
 285                         if (i < writer.selected_nr - 1 &&
 286                             (need_reset ||
 287                              !in_merge_bases(writer.selected[i + 1].commit,
 288                                              stored->commit))) {
 289                             bitmap_reset(base);
 290                             reset_all_seen();
 291                         }
 292
 293                         add_pending_object(&revs, object, "");
 294                         revs.include_check_data = base;
 295
 296                         if (prepare_revision_walk(&revs))
 297                                 die("revision walk setup failed");
 298
 299                         traverse_commit_list(&revs, show_commit, show_object, base);
 300
 301                         object_array_clear(&revs.pending);
 302
 303                         stored->bitmap = bitmap_to_ewah(base);
 304                         need_reset = 0;
 305                 } else
 306                         need_reset = 1;
 307
 308                 if (i >= reuse_after)
 309                         stored->flags |= BITMAP_FLAG_REUSE;
 310
 311                 hash_pos = kh_put_sha1(writer.bitmaps, object->oid.hash, &hash_ret);
 312                 if (hash_ret == 0)
 313                         die("Duplicate entry when writing index: %s",
 314                             oid_to_hex(&object->oid));
 315
 316                 kh_value(writer.bitmaps, hash_pos) = stored;
 317                 display_progress(writer.progress, writer.selected_nr - i);
 318         }
 319
 320         bitmap_free(base);
 321         stop_progress(&writer.progress);
 322
 323         compute_xor_offsets();
 324 }
 325
 326 /**
 327  * Select the commits that will be bitmapped
 328  */
 329 static inline unsigned int next_commit_index(unsigned int idx)
 330 {
 331         static const unsigned int MIN_COMMITS = 100;
 332         static const unsigned int MAX_COMMITS = 5000;
 333
 334         static const unsigned int MUST_REGION = 100;
 335         static const unsigned int MIN_REGION = 20000;
 336
 337         unsigned int offset, next;
 338
 339         if (idx <= MUST_REGION)
 340                 return 0;
 341
 342         if (idx <= MIN_REGION) {
 343                 offset = idx - MUST_REGION;
 344                 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
 345         }
 346
 347         offset = idx - MIN_REGION;
 348         next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
 349
 350         return (next > MIN_COMMITS) ? next : MIN_COMMITS;
 351 }
 352
 353 static int date_compare(const void *_a, const void *_b)
 354 {
 355         struct commit *a = *(struct commit **)_a;
 356         struct commit *b = *(struct commit **)_b;
 357         return (long)b->date - (long)a->date;
 358 }
 359
 360 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
 361 {
 362         if (prepare_bitmap_git() < 0)
 363                 return;
 364
 365         writer.reused = kh_init_sha1();
 366         rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
 367 }
 368
 369 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
 370 {
 371         khiter_t hash_pos;
 372
 373         if (!writer.reused)
 374                 return NULL;
 375
 376         hash_pos = kh_get_sha1(writer.reused, sha1);
 377         if (hash_pos >= kh_end(writer.reused))
 378                 return NULL;
 379
 380         return kh_value(writer.reused, hash_pos);
 381 }
 382
 383 void bitmap_writer_select_commits(struct commit **indexed_commits,
 384                                   unsigned int indexed_commits_nr,
 385                                   int max_bitmaps)
 386 {
 387         unsigned int i = 0, j, next;
 388
 389         QSORT(indexed_commits, indexed_commits_nr, date_compare);
 390
 391         if (writer.show_progress)
 392                 writer.progress = start_progress("Selecting bitmap commits", 0);
 393
 394         if (indexed_commits_nr < 100) {
 395                 for (i = 0; i < indexed_commits_nr; ++i)
 396                         push_bitmapped_commit(indexed_commits[i], NULL);
 397                 return;
 398         }
 399
 400         for (;;) {
 401                 struct ewah_bitmap *reused_bitmap = NULL;
 402                 struct commit *chosen = NULL;
 403
 404                 next = next_commit_index(i);
 405
 406                 if (i + next >= indexed_commits_nr)
 407                         break;
 408
 409                 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
 410                         writer.selected_nr = max_bitmaps;
 411                         break;
 412                 }
 413
 414                 if (next == 0) {
 415                         chosen = indexed_commits[i];
 416                         reused_bitmap = find_reused_bitmap(chosen->object.oid.hash);
 417                 } else {
 418                         chosen = indexed_commits[i + next];
 419
 420                         for (j = 0; j <= next; ++j) {
 421                                 struct commit *cm = indexed_commits[i + j];
 422
 423                                 reused_bitmap = find_reused_bitmap(cm->object.oid.hash);
 424                                 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
 425                                         chosen = cm;
 426                                         break;
 427                                 }
 428
 429                                 if (cm->parents && cm->parents->next)
 430                                         chosen = cm;
 431                         }
 432                 }
 433
 434                 push_bitmapped_commit(chosen, reused_bitmap);
 435
 436                 i += next + 1;
 437                 display_progress(writer.progress, i);
 438         }
 439
 440         stop_progress(&writer.progress);
 441 }
 442
 443
 444 static int hashwrite_ewah_helper(void *f, const void *buf, size_t len)
 445 {
 446         /* hashwrite will die on error */
 447         hashwrite(f, buf, len);
 448         return len;
 449 }
 450
 451 /**
 452  * Write the bitmap index to disk
 453  */
 454 static inline void dump_bitmap(struct hashfile *f, struct ewah_bitmap *bitmap)
 455 {
 456         if (ewah_serialize_to(bitmap, hashwrite_ewah_helper, f) < 0)
 457                 die("Failed to write bitmap index");
 458 }
 459
 460 static const unsigned char *sha1_access(size_t pos, void *table)
 461 {
 462         struct pack_idx_entry **index = table;
 463         return index[pos]->oid.hash;
 464 }
 465
 466 static void write_selected_commits_v1(struct hashfile *f,
 467                                       struct pack_idx_entry **index,
 468                                       uint32_t index_nr)
 469 {
 470         int i;
 471
 472         for (i = 0; i < writer.selected_nr; ++i) {
 473                 struct bitmapped_commit *stored = &writer.selected[i];
 474
 475                 int commit_pos =
 476                         sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
 477
 478                 if (commit_pos < 0)
 479                         die("BUG: trying to write commit not in index");
 480
 481                 hashwrite_be32(f, commit_pos);
 482                 hashwrite_u8(f, stored->xor_offset);
 483                 hashwrite_u8(f, stored->flags);
 484
 485                 dump_bitmap(f, stored->write_as);
 486         }
 487 }
 488
 489 static void write_hash_cache(struct hashfile *f,
 490                              struct pack_idx_entry **index,
 491                              uint32_t index_nr)
 492 {
 493         uint32_t i;
 494
 495         for (i = 0; i < index_nr; ++i) {
 496                 struct object_entry *entry = (struct object_entry *)index[i];
 497                 uint32_t hash_value = htonl(entry->hash);
 498                 hashwrite(f, &hash_value, sizeof(hash_value));
 499         }
 500 }
 501
 502 void bitmap_writer_set_checksum(unsigned char *sha1)
 503 {
 504         hashcpy(writer.pack_checksum, sha1);
 505 }
 506
 507 void bitmap_writer_finish(struct pack_idx_entry **index,
 508                           uint32_t index_nr,
 509                           const char *filename,
 510                           uint16_t options)
 511 {
 512         static uint16_t default_version = 1;
 513         static uint16_t flags = BITMAP_OPT_FULL_DAG;
 514         struct strbuf tmp_file = STRBUF_INIT;
 515         struct hashfile *f;
 516
 517         struct bitmap_disk_header header;
 518
 519         int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
 520
 521         f = hashfd(fd, tmp_file.buf);
 522
 523         memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 524         header.version = htons(default_version);
 525         header.options = htons(flags | options);
 526         header.entry_count = htonl(writer.selected_nr);
 527         hashcpy(header.checksum, writer.pack_checksum);
 528
 529         hashwrite(f, &header, sizeof(header));
 530         dump_bitmap(f, writer.commits);
 531         dump_bitmap(f, writer.trees);
 532         dump_bitmap(f, writer.blobs);
 533         dump_bitmap(f, writer.tags);
 534         write_selected_commits_v1(f, index, index_nr);
 535
 536         if (options & BITMAP_OPT_HASH_CACHE)
 537                 write_hash_cache(f, index, index_nr);
 538
 539         hashclose(f, NULL, CSUM_FSYNC);
 540
 541         if (adjust_shared_perm(tmp_file.buf))
 542                 die_errno("unable to make temporary bitmap file readable");
 543
 544         if (rename(tmp_file.buf, filename))
 545                 die_errno("unable to rename temporary bitmap file to '%s'", filename);
 546
 547         strbuf_release(&tmp_file);
 548 }