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 "hash-lookup.h"
13 #include "pack-objects.h"
14 #include "commit-reach.h"
15 #include "prio-queue.h"
16
17 struct bitmapped_commit {
18 struct commit *commit;
19 struct ewah_bitmap *bitmap;
20 struct ewah_bitmap *write_as;
21 int flags;
22 int xor_offset;
23 uint32_t commit_pos;
24 };
25
26 struct bitmap_writer {
27 struct ewah_bitmap *commits;
28 struct ewah_bitmap *trees;
29 struct ewah_bitmap *blobs;
30 struct ewah_bitmap *tags;
31
32 kh_oid_map_t *bitmaps;
33 struct packing_data *to_pack;
34
35 struct bitmapped_commit *selected;
36 unsigned int selected_nr, selected_alloc;
37
38 struct progress *progress;
39 int show_progress;
40 unsigned char pack_checksum[GIT_MAX_RAWSZ];
41 };
42
43 static struct bitmap_writer writer;
44
bitmap_writer_show_progress(int show)45 void bitmap_writer_show_progress(int show)
46 {
47 writer.show_progress = show;
48 }
49
50 /**
51 * Build the initial type index for the packfile or multi-pack-index
52 */
bitmap_writer_build_type_index(struct packing_data * to_pack,struct pack_idx_entry ** index,uint32_t index_nr)53 void bitmap_writer_build_type_index(struct packing_data *to_pack,
54 struct pack_idx_entry **index,
55 uint32_t index_nr)
56 {
57 uint32_t i;
58
59 writer.commits = ewah_new();
60 writer.trees = ewah_new();
61 writer.blobs = ewah_new();
62 writer.tags = ewah_new();
63 ALLOC_ARRAY(to_pack->in_pack_pos, to_pack->nr_objects);
64
65 for (i = 0; i < index_nr; ++i) {
66 struct object_entry *entry = (struct object_entry *)index[i];
67 enum object_type real_type;
68
69 oe_set_in_pack_pos(to_pack, entry, i);
70
71 switch (oe_type(entry)) {
72 case OBJ_COMMIT:
73 case OBJ_TREE:
74 case OBJ_BLOB:
75 case OBJ_TAG:
76 real_type = oe_type(entry);
77 break;
78
79 default:
80 real_type = oid_object_info(to_pack->repo,
81 &entry->idx.oid, NULL);
82 break;
83 }
84
85 switch (real_type) {
86 case OBJ_COMMIT:
87 ewah_set(writer.commits, i);
88 break;
89
90 case OBJ_TREE:
91 ewah_set(writer.trees, i);
92 break;
93
94 case OBJ_BLOB:
95 ewah_set(writer.blobs, i);
96 break;
97
98 case OBJ_TAG:
99 ewah_set(writer.tags, i);
100 break;
101
102 default:
103 die("Missing type information for %s (%d/%d)",
104 oid_to_hex(&entry->idx.oid), real_type,
105 oe_type(entry));
106 }
107 }
108 }
109
110 /**
111 * Compute the actual bitmaps
112 */
113
push_bitmapped_commit(struct commit * commit)114 static inline void push_bitmapped_commit(struct commit *commit)
115 {
116 if (writer.selected_nr >= writer.selected_alloc) {
117 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
118 REALLOC_ARRAY(writer.selected, writer.selected_alloc);
119 }
120
121 writer.selected[writer.selected_nr].commit = commit;
122 writer.selected[writer.selected_nr].bitmap = NULL;
123 writer.selected[writer.selected_nr].flags = 0;
124
125 writer.selected_nr++;
126 }
127
find_object_pos(const struct object_id * oid,int * found)128 static uint32_t find_object_pos(const struct object_id *oid, int *found)
129 {
130 struct object_entry *entry = packlist_find(writer.to_pack, oid);
131
132 if (!entry) {
133 if (found)
134 *found = 0;
135 warning("Failed to write bitmap index. Packfile doesn't have full closure "
136 "(object %s is missing)", oid_to_hex(oid));
137 return 0;
138 }
139
140 if (found)
141 *found = 1;
142 return oe_in_pack_pos(writer.to_pack, entry);
143 }
144
compute_xor_offsets(void)145 static void compute_xor_offsets(void)
146 {
147 static const int MAX_XOR_OFFSET_SEARCH = 10;
148
149 int i, next = 0;
150
151 while (next < writer.selected_nr) {
152 struct bitmapped_commit *stored = &writer.selected[next];
153
154 int best_offset = 0;
155 struct ewah_bitmap *best_bitmap = stored->bitmap;
156 struct ewah_bitmap *test_xor;
157
158 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
159 int curr = next - i;
160
161 if (curr < 0)
162 break;
163
164 test_xor = ewah_pool_new();
165 ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
166
167 if (test_xor->buffer_size < best_bitmap->buffer_size) {
168 if (best_bitmap != stored->bitmap)
169 ewah_pool_free(best_bitmap);
170
171 best_bitmap = test_xor;
172 best_offset = i;
173 } else {
174 ewah_pool_free(test_xor);
175 }
176 }
177
178 stored->xor_offset = best_offset;
179 stored->write_as = best_bitmap;
180
181 next++;
182 }
183 }
184
185 struct bb_commit {
186 struct commit_list *reverse_edges;
187 struct bitmap *commit_mask;
188 struct bitmap *bitmap;
189 unsigned selected:1,
190 maximal:1;
191 unsigned idx; /* within selected array */
192 };
193
194 define_commit_slab(bb_data, struct bb_commit);
195
196 struct bitmap_builder {
197 struct bb_data data;
198 struct commit **commits;
199 size_t commits_nr, commits_alloc;
200 };
201
bitmap_builder_init(struct bitmap_builder * bb,struct bitmap_writer * writer,struct bitmap_index * old_bitmap)202 static void bitmap_builder_init(struct bitmap_builder *bb,
203 struct bitmap_writer *writer,
204 struct bitmap_index *old_bitmap)
205 {
206 struct rev_info revs;
207 struct commit *commit;
208 struct commit_list *reusable = NULL;
209 struct commit_list *r;
210 unsigned int i, num_maximal = 0;
211
212 memset(bb, 0, sizeof(*bb));
213 init_bb_data(&bb->data);
214
215 reset_revision_walk();
216 repo_init_revisions(writer->to_pack->repo, &revs, NULL);
217 revs.topo_order = 1;
218 revs.first_parent_only = 1;
219
220 for (i = 0; i < writer->selected_nr; i++) {
221 struct commit *c = writer->selected[i].commit;
222 struct bb_commit *ent = bb_data_at(&bb->data, c);
223
224 ent->selected = 1;
225 ent->maximal = 1;
226 ent->idx = i;
227
228 ent->commit_mask = bitmap_new();
229 bitmap_set(ent->commit_mask, i);
230
231 add_pending_object(&revs, &c->object, "");
232 }
233
234 if (prepare_revision_walk(&revs))
235 die("revision walk setup failed");
236
237 while ((commit = get_revision(&revs))) {
238 struct commit_list *p = commit->parents;
239 struct bb_commit *c_ent;
240
241 parse_commit_or_die(commit);
242
243 c_ent = bb_data_at(&bb->data, commit);
244
245 /*
246 * If there is no commit_mask, there is no reason to iterate
247 * over this commit; it is not selected (if it were, it would
248 * not have a blank commit mask) and all its children have
249 * existing bitmaps (see the comment starting with "This commit
250 * has an existing bitmap" below), so it does not contribute
251 * anything to the final bitmap file or its descendants.
252 */
253 if (!c_ent->commit_mask)
254 continue;
255
256 if (old_bitmap && bitmap_for_commit(old_bitmap, commit)) {
257 /*
258 * This commit has an existing bitmap, so we can
259 * get its bits immediately without an object
260 * walk. That is, it is reusable as-is and there is no
261 * need to continue walking beyond it.
262 *
263 * Mark it as such and add it to bb->commits separately
264 * to avoid allocating a position in the commit mask.
265 */
266 commit_list_insert(commit, &reusable);
267 goto next;
268 }
269
270 if (c_ent->maximal) {
271 num_maximal++;
272 ALLOC_GROW(bb->commits, bb->commits_nr + 1, bb->commits_alloc);
273 bb->commits[bb->commits_nr++] = commit;
274 }
275
276 if (p) {
277 struct bb_commit *p_ent = bb_data_at(&bb->data, p->item);
278 int c_not_p, p_not_c;
279
280 if (!p_ent->commit_mask) {
281 p_ent->commit_mask = bitmap_new();
282 c_not_p = 1;
283 p_not_c = 0;
284 } else {
285 c_not_p = bitmap_is_subset(c_ent->commit_mask, p_ent->commit_mask);
286 p_not_c = bitmap_is_subset(p_ent->commit_mask, c_ent->commit_mask);
287 }
288
289 if (!c_not_p)
290 continue;
291
292 bitmap_or(p_ent->commit_mask, c_ent->commit_mask);
293
294 if (p_not_c)
295 p_ent->maximal = 1;
296 else {
297 p_ent->maximal = 0;
298 free_commit_list(p_ent->reverse_edges);
299 p_ent->reverse_edges = NULL;
300 }
301
302 if (c_ent->maximal) {
303 commit_list_insert(commit, &p_ent->reverse_edges);
304 } else {
305 struct commit_list *cc = c_ent->reverse_edges;
306
307 for (; cc; cc = cc->next) {
308 if (!commit_list_contains(cc->item, p_ent->reverse_edges))
309 commit_list_insert(cc->item, &p_ent->reverse_edges);
310 }
311 }
312 }
313
314 next:
315 bitmap_free(c_ent->commit_mask);
316 c_ent->commit_mask = NULL;
317 }
318
319 for (r = reusable; r; r = r->next) {
320 ALLOC_GROW(bb->commits, bb->commits_nr + 1, bb->commits_alloc);
321 bb->commits[bb->commits_nr++] = r->item;
322 }
323
324 trace2_data_intmax("pack-bitmap-write", the_repository,
325 "num_selected_commits", writer->selected_nr);
326 trace2_data_intmax("pack-bitmap-write", the_repository,
327 "num_maximal_commits", num_maximal);
328
329 free_commit_list(reusable);
330 }
331
bitmap_builder_clear(struct bitmap_builder * bb)332 static void bitmap_builder_clear(struct bitmap_builder *bb)
333 {
334 clear_bb_data(&bb->data);
335 free(bb->commits);
336 bb->commits_nr = bb->commits_alloc = 0;
337 }
338
fill_bitmap_tree(struct bitmap * bitmap,struct tree * tree)339 static int fill_bitmap_tree(struct bitmap *bitmap,
340 struct tree *tree)
341 {
342 int found;
343 uint32_t pos;
344 struct tree_desc desc;
345 struct name_entry entry;
346
347 /*
348 * If our bit is already set, then there is nothing to do. Both this
349 * tree and all of its children will be set.
350 */
351 pos = find_object_pos(&tree->object.oid, &found);
352 if (!found)
353 return -1;
354 if (bitmap_get(bitmap, pos))
355 return 0;
356 bitmap_set(bitmap, pos);
357
358 if (parse_tree(tree) < 0)
359 die("unable to load tree object %s",
360 oid_to_hex(&tree->object.oid));
361 init_tree_desc(&desc, tree->buffer, tree->size);
362
363 while (tree_entry(&desc, &entry)) {
364 switch (object_type(entry.mode)) {
365 case OBJ_TREE:
366 if (fill_bitmap_tree(bitmap,
367 lookup_tree(the_repository, &entry.oid)) < 0)
368 return -1;
369 break;
370 case OBJ_BLOB:
371 pos = find_object_pos(&entry.oid, &found);
372 if (!found)
373 return -1;
374 bitmap_set(bitmap, pos);
375 break;
376 default:
377 /* Gitlink, etc; not reachable */
378 break;
379 }
380 }
381
382 free_tree_buffer(tree);
383 return 0;
384 }
385
fill_bitmap_commit(struct bb_commit * ent,struct commit * commit,struct prio_queue * queue,struct prio_queue * tree_queue,struct bitmap_index * old_bitmap,const uint32_t * mapping)386 static int fill_bitmap_commit(struct bb_commit *ent,
387 struct commit *commit,
388 struct prio_queue *queue,
389 struct prio_queue *tree_queue,
390 struct bitmap_index *old_bitmap,
391 const uint32_t *mapping)
392 {
393 int found;
394 uint32_t pos;
395 if (!ent->bitmap)
396 ent->bitmap = bitmap_new();
397
398 prio_queue_put(queue, commit);
399
400 while (queue->nr) {
401 struct commit_list *p;
402 struct commit *c = prio_queue_get(queue);
403
404 if (old_bitmap && mapping) {
405 struct ewah_bitmap *old = bitmap_for_commit(old_bitmap, c);
406 /*
407 * If this commit has an old bitmap, then translate that
408 * bitmap and add its bits to this one. No need to walk
409 * parents or the tree for this commit.
410 */
411 if (old && !rebuild_bitmap(mapping, old, ent->bitmap))
412 continue;
413 }
414
415 /*
416 * Mark ourselves and queue our tree. The commit
417 * walk ensures we cover all parents.
418 */
419 pos = find_object_pos(&c->object.oid, &found);
420 if (!found)
421 return -1;
422 bitmap_set(ent->bitmap, pos);
423 prio_queue_put(tree_queue, get_commit_tree(c));
424
425 for (p = c->parents; p; p = p->next) {
426 pos = find_object_pos(&p->item->object.oid, &found);
427 if (!found)
428 return -1;
429 if (!bitmap_get(ent->bitmap, pos)) {
430 bitmap_set(ent->bitmap, pos);
431 prio_queue_put(queue, p->item);
432 }
433 }
434 }
435
436 while (tree_queue->nr) {
437 if (fill_bitmap_tree(ent->bitmap,
438 prio_queue_get(tree_queue)) < 0)
439 return -1;
440 }
441 return 0;
442 }
443
store_selected(struct bb_commit * ent,struct commit * commit)444 static void store_selected(struct bb_commit *ent, struct commit *commit)
445 {
446 struct bitmapped_commit *stored = &writer.selected[ent->idx];
447 khiter_t hash_pos;
448 int hash_ret;
449
450 stored->bitmap = bitmap_to_ewah(ent->bitmap);
451
452 hash_pos = kh_put_oid_map(writer.bitmaps, commit->object.oid, &hash_ret);
453 if (hash_ret == 0)
454 die("Duplicate entry when writing index: %s",
455 oid_to_hex(&commit->object.oid));
456 kh_value(writer.bitmaps, hash_pos) = stored;
457 }
458
bitmap_writer_build(struct packing_data * to_pack)459 int bitmap_writer_build(struct packing_data *to_pack)
460 {
461 struct bitmap_builder bb;
462 size_t i;
463 int nr_stored = 0; /* for progress */
464 struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
465 struct prio_queue tree_queue = { NULL };
466 struct bitmap_index *old_bitmap;
467 uint32_t *mapping;
468 int closed = 1; /* until proven otherwise */
469
470 writer.bitmaps = kh_init_oid_map();
471 writer.to_pack = to_pack;
472
473 if (writer.show_progress)
474 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
475 trace2_region_enter("pack-bitmap-write", "building_bitmaps_total",
476 the_repository);
477
478 old_bitmap = prepare_bitmap_git(to_pack->repo);
479 if (old_bitmap)
480 mapping = create_bitmap_mapping(old_bitmap, to_pack);
481 else
482 mapping = NULL;
483
484 bitmap_builder_init(&bb, &writer, old_bitmap);
485 for (i = bb.commits_nr; i > 0; i--) {
486 struct commit *commit = bb.commits[i-1];
487 struct bb_commit *ent = bb_data_at(&bb.data, commit);
488 struct commit *child;
489 int reused = 0;
490
491 if (fill_bitmap_commit(ent, commit, &queue, &tree_queue,
492 old_bitmap, mapping) < 0) {
493 closed = 0;
494 break;
495 }
496
497 if (ent->selected) {
498 store_selected(ent, commit);
499 nr_stored++;
500 display_progress(writer.progress, nr_stored);
501 }
502
503 while ((child = pop_commit(&ent->reverse_edges))) {
504 struct bb_commit *child_ent =
505 bb_data_at(&bb.data, child);
506
507 if (child_ent->bitmap)
508 bitmap_or(child_ent->bitmap, ent->bitmap);
509 else if (reused)
510 child_ent->bitmap = bitmap_dup(ent->bitmap);
511 else {
512 child_ent->bitmap = ent->bitmap;
513 reused = 1;
514 }
515 }
516 if (!reused)
517 bitmap_free(ent->bitmap);
518 ent->bitmap = NULL;
519 }
520 clear_prio_queue(&queue);
521 clear_prio_queue(&tree_queue);
522 bitmap_builder_clear(&bb);
523 free_bitmap_index(old_bitmap);
524 free(mapping);
525
526 trace2_region_leave("pack-bitmap-write", "building_bitmaps_total",
527 the_repository);
528
529 stop_progress(&writer.progress);
530
531 if (closed)
532 compute_xor_offsets();
533 return closed ? 0 : -1;
534 }
535
536 /**
537 * Select the commits that will be bitmapped
538 */
next_commit_index(unsigned int idx)539 static inline unsigned int next_commit_index(unsigned int idx)
540 {
541 static const unsigned int MIN_COMMITS = 100;
542 static const unsigned int MAX_COMMITS = 5000;
543
544 static const unsigned int MUST_REGION = 100;
545 static const unsigned int MIN_REGION = 20000;
546
547 unsigned int offset, next;
548
549 if (idx <= MUST_REGION)
550 return 0;
551
552 if (idx <= MIN_REGION) {
553 offset = idx - MUST_REGION;
554 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
555 }
556
557 offset = idx - MIN_REGION;
558 next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
559
560 return (next > MIN_COMMITS) ? next : MIN_COMMITS;
561 }
562
date_compare(const void * _a,const void * _b)563 static int date_compare(const void *_a, const void *_b)
564 {
565 struct commit *a = *(struct commit **)_a;
566 struct commit *b = *(struct commit **)_b;
567 return (long)b->date - (long)a->date;
568 }
569
bitmap_writer_select_commits(struct commit ** indexed_commits,unsigned int indexed_commits_nr,int max_bitmaps)570 void bitmap_writer_select_commits(struct commit **indexed_commits,
571 unsigned int indexed_commits_nr,
572 int max_bitmaps)
573 {
574 unsigned int i = 0, j, next;
575
576 QSORT(indexed_commits, indexed_commits_nr, date_compare);
577
578 if (writer.show_progress)
579 writer.progress = start_progress("Selecting bitmap commits", 0);
580
581 if (indexed_commits_nr < 100) {
582 for (i = 0; i < indexed_commits_nr; ++i)
583 push_bitmapped_commit(indexed_commits[i]);
584 return;
585 }
586
587 for (;;) {
588 struct commit *chosen = NULL;
589
590 next = next_commit_index(i);
591
592 if (i + next >= indexed_commits_nr)
593 break;
594
595 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
596 writer.selected_nr = max_bitmaps;
597 break;
598 }
599
600 if (next == 0) {
601 chosen = indexed_commits[i];
602 } else {
603 chosen = indexed_commits[i + next];
604
605 for (j = 0; j <= next; ++j) {
606 struct commit *cm = indexed_commits[i + j];
607
608 if ((cm->object.flags & NEEDS_BITMAP) != 0) {
609 chosen = cm;
610 break;
611 }
612
613 if (cm->parents && cm->parents->next)
614 chosen = cm;
615 }
616 }
617
618 push_bitmapped_commit(chosen);
619
620 i += next + 1;
621 display_progress(writer.progress, i);
622 }
623
624 stop_progress(&writer.progress);
625 }
626
627
hashwrite_ewah_helper(void * f,const void * buf,size_t len)628 static int hashwrite_ewah_helper(void *f, const void *buf, size_t len)
629 {
630 /* hashwrite will die on error */
631 hashwrite(f, buf, len);
632 return len;
633 }
634
635 /**
636 * Write the bitmap index to disk
637 */
dump_bitmap(struct hashfile * f,struct ewah_bitmap * bitmap)638 static inline void dump_bitmap(struct hashfile *f, struct ewah_bitmap *bitmap)
639 {
640 if (ewah_serialize_to(bitmap, hashwrite_ewah_helper, f) < 0)
641 die("Failed to write bitmap index");
642 }
643
oid_access(size_t pos,const void * table)644 static const struct object_id *oid_access(size_t pos, const void *table)
645 {
646 const struct pack_idx_entry * const *index = table;
647 return &index[pos]->oid;
648 }
649
write_selected_commits_v1(struct hashfile * f,struct pack_idx_entry ** index,uint32_t index_nr)650 static void write_selected_commits_v1(struct hashfile *f,
651 struct pack_idx_entry **index,
652 uint32_t index_nr)
653 {
654 int i;
655
656 for (i = 0; i < writer.selected_nr; ++i) {
657 struct bitmapped_commit *stored = &writer.selected[i];
658
659 int commit_pos =
660 oid_pos(&stored->commit->object.oid, index, index_nr, oid_access);
661
662 if (commit_pos < 0)
663 BUG("trying to write commit not in index");
664
665 hashwrite_be32(f, commit_pos);
666 hashwrite_u8(f, stored->xor_offset);
667 hashwrite_u8(f, stored->flags);
668
669 dump_bitmap(f, stored->write_as);
670 }
671 }
672
write_hash_cache(struct hashfile * f,struct pack_idx_entry ** index,uint32_t index_nr)673 static void write_hash_cache(struct hashfile *f,
674 struct pack_idx_entry **index,
675 uint32_t index_nr)
676 {
677 uint32_t i;
678
679 for (i = 0; i < index_nr; ++i) {
680 struct object_entry *entry = (struct object_entry *)index[i];
681 hashwrite_be32(f, entry->hash);
682 }
683 }
684
bitmap_writer_set_checksum(unsigned char * sha1)685 void bitmap_writer_set_checksum(unsigned char *sha1)
686 {
687 hashcpy(writer.pack_checksum, sha1);
688 }
689
bitmap_writer_finish(struct pack_idx_entry ** index,uint32_t index_nr,const char * filename,uint16_t options)690 void bitmap_writer_finish(struct pack_idx_entry **index,
691 uint32_t index_nr,
692 const char *filename,
693 uint16_t options)
694 {
695 static uint16_t default_version = 1;
696 static uint16_t flags = BITMAP_OPT_FULL_DAG;
697 struct strbuf tmp_file = STRBUF_INIT;
698 struct hashfile *f;
699
700 struct bitmap_disk_header header;
701
702 int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
703
704 f = hashfd(fd, tmp_file.buf);
705
706 memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
707 header.version = htons(default_version);
708 header.options = htons(flags | options);
709 header.entry_count = htonl(writer.selected_nr);
710 hashcpy(header.checksum, writer.pack_checksum);
711
712 hashwrite(f, &header, sizeof(header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz);
713 dump_bitmap(f, writer.commits);
714 dump_bitmap(f, writer.trees);
715 dump_bitmap(f, writer.blobs);
716 dump_bitmap(f, writer.tags);
717 write_selected_commits_v1(f, index, index_nr);
718
719 if (options & BITMAP_OPT_HASH_CACHE)
720 write_hash_cache(f, index, index_nr);
721
722 finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
723
724 if (adjust_shared_perm(tmp_file.buf))
725 die_errno("unable to make temporary bitmap file readable");
726
727 if (rename(tmp_file.buf, filename))
728 die_errno("unable to rename temporary bitmap file to '%s'", filename);
729
730 strbuf_release(&tmp_file);
731 }
732