pack-bitmap-write.c

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