repack: introduce repack.writeBitmaps config option
[git.git] / pack-bitmap-write.c
blob1218befaf2afa2f0be4be8a582a1f85bab334ed2
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"
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;
23 struct bitmap_writer {
24 struct ewah_bitmap *commits;
25 struct ewah_bitmap *trees;
26 struct ewah_bitmap *blobs;
27 struct ewah_bitmap *tags;
29 khash_sha1 *bitmaps;
30 khash_sha1 *reused;
31 struct packing_data *to_pack;
33 struct bitmapped_commit *selected;
34 unsigned int selected_nr, selected_alloc;
36 struct progress *progress;
37 int show_progress;
38 unsigned char pack_checksum[20];
41 static struct bitmap_writer writer;
43 void bitmap_writer_show_progress(int show)
45 writer.show_progress = show;
48 /**
49 * Build the initial type index for the packfile
51 void bitmap_writer_build_type_index(struct pack_idx_entry **index,
52 uint32_t index_nr)
54 uint32_t i;
56 writer.commits = ewah_new();
57 writer.trees = ewah_new();
58 writer.blobs = ewah_new();
59 writer.tags = ewah_new();
61 for (i = 0; i < index_nr; ++i) {
62 struct object_entry *entry = (struct object_entry *)index[i];
63 enum object_type real_type;
65 entry->in_pack_pos = i;
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;
75 default:
76 real_type = sha1_object_info(entry->idx.sha1, NULL);
77 break;
80 switch (real_type) {
81 case OBJ_COMMIT:
82 ewah_set(writer.commits, i);
83 break;
85 case OBJ_TREE:
86 ewah_set(writer.trees, i);
87 break;
89 case OBJ_BLOB:
90 ewah_set(writer.blobs, i);
91 break;
93 case OBJ_TAG:
94 ewah_set(writer.tags, i);
95 break;
97 default:
98 die("Missing type information for %s (%d/%d)",
99 sha1_to_hex(entry->idx.sha1), real_type, entry->type);
105 * Compute the actual bitmaps
107 static struct object **seen_objects;
108 static unsigned int seen_objects_nr, seen_objects_alloc;
110 static inline void push_bitmapped_commit(struct commit *commit, struct ewah_bitmap *reused)
112 if (writer.selected_nr >= writer.selected_alloc) {
113 writer.selected_alloc = (writer.selected_alloc + 32) * 2;
114 writer.selected = xrealloc(writer.selected,
115 writer.selected_alloc * sizeof(struct bitmapped_commit));
118 writer.selected[writer.selected_nr].commit = commit;
119 writer.selected[writer.selected_nr].bitmap = reused;
120 writer.selected[writer.selected_nr].flags = 0;
122 writer.selected_nr++;
125 static inline void mark_as_seen(struct object *object)
127 ALLOC_GROW(seen_objects, seen_objects_nr + 1, seen_objects_alloc);
128 seen_objects[seen_objects_nr++] = object;
131 static inline void reset_all_seen(void)
133 unsigned int i;
134 for (i = 0; i < seen_objects_nr; ++i) {
135 seen_objects[i]->flags &= ~(SEEN | ADDED | SHOWN);
137 seen_objects_nr = 0;
140 static uint32_t find_object_pos(const unsigned char *sha1)
142 struct object_entry *entry = packlist_find(writer.to_pack, sha1, NULL);
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));
149 return entry->in_pack_pos;
152 static void show_object(struct object *object, const struct name_path *path,
153 const char *last, void *data)
155 struct bitmap *base = data;
156 bitmap_set(base, find_object_pos(object->sha1));
157 mark_as_seen(object);
160 static void show_commit(struct commit *commit, void *data)
162 mark_as_seen((struct object *)commit);
165 static int
166 add_to_include_set(struct bitmap *base, struct commit *commit)
168 khiter_t hash_pos;
169 uint32_t bitmap_pos = find_object_pos(commit->object.sha1);
171 if (bitmap_get(base, bitmap_pos))
172 return 0;
174 hash_pos = kh_get_sha1(writer.bitmaps, commit->object.sha1);
175 if (hash_pos < kh_end(writer.bitmaps)) {
176 struct bitmapped_commit *bc = kh_value(writer.bitmaps, hash_pos);
177 bitmap_or_ewah(base, bc->bitmap);
178 return 0;
181 bitmap_set(base, bitmap_pos);
182 return 1;
185 static int
186 should_include(struct commit *commit, void *_data)
188 struct bitmap *base = _data;
190 if (!add_to_include_set(base, commit)) {
191 struct commit_list *parent = commit->parents;
193 mark_as_seen((struct object *)commit);
195 while (parent) {
196 parent->item->object.flags |= SEEN;
197 mark_as_seen((struct object *)parent->item);
198 parent = parent->next;
201 return 0;
204 return 1;
207 static void compute_xor_offsets(void)
209 static const int MAX_XOR_OFFSET_SEARCH = 10;
211 int i, next = 0;
213 while (next < writer.selected_nr) {
214 struct bitmapped_commit *stored = &writer.selected[next];
216 int best_offset = 0;
217 struct ewah_bitmap *best_bitmap = stored->bitmap;
218 struct ewah_bitmap *test_xor;
220 for (i = 1; i <= MAX_XOR_OFFSET_SEARCH; ++i) {
221 int curr = next - i;
223 if (curr < 0)
224 break;
226 test_xor = ewah_pool_new();
227 ewah_xor(writer.selected[curr].bitmap, stored->bitmap, test_xor);
229 if (test_xor->buffer_size < best_bitmap->buffer_size) {
230 if (best_bitmap != stored->bitmap)
231 ewah_pool_free(best_bitmap);
233 best_bitmap = test_xor;
234 best_offset = i;
235 } else {
236 ewah_pool_free(test_xor);
240 stored->xor_offset = best_offset;
241 stored->write_as = best_bitmap;
243 next++;
247 void bitmap_writer_build(struct packing_data *to_pack)
249 static const double REUSE_BITMAP_THRESHOLD = 0.2;
251 int i, reuse_after, need_reset;
252 struct bitmap *base = bitmap_new();
253 struct rev_info revs;
255 writer.bitmaps = kh_init_sha1();
256 writer.to_pack = to_pack;
258 if (writer.show_progress)
259 writer.progress = start_progress("Building bitmaps", writer.selected_nr);
261 init_revisions(&revs, NULL);
262 revs.tag_objects = 1;
263 revs.tree_objects = 1;
264 revs.blob_objects = 1;
265 revs.no_walk = 0;
267 revs.include_check = should_include;
268 reset_revision_walk();
270 reuse_after = writer.selected_nr * REUSE_BITMAP_THRESHOLD;
271 need_reset = 0;
273 for (i = writer.selected_nr - 1; i >= 0; --i) {
274 struct bitmapped_commit *stored;
275 struct object *object;
277 khiter_t hash_pos;
278 int hash_ret;
280 stored = &writer.selected[i];
281 object = (struct object *)stored->commit;
283 if (stored->bitmap == NULL) {
284 if (i < writer.selected_nr - 1 &&
285 (need_reset ||
286 !in_merge_bases(writer.selected[i + 1].commit,
287 stored->commit))) {
288 bitmap_reset(base);
289 reset_all_seen();
292 add_pending_object(&revs, object, "");
293 revs.include_check_data = base;
295 if (prepare_revision_walk(&revs))
296 die("revision walk setup failed");
298 traverse_commit_list(&revs, show_commit, show_object, base);
300 revs.pending.nr = 0;
301 revs.pending.alloc = 0;
302 revs.pending.objects = NULL;
304 stored->bitmap = bitmap_to_ewah(base);
305 need_reset = 0;
306 } else
307 need_reset = 1;
309 if (i >= reuse_after)
310 stored->flags |= BITMAP_FLAG_REUSE;
312 hash_pos = kh_put_sha1(writer.bitmaps, object->sha1, &hash_ret);
313 if (hash_ret == 0)
314 die("Duplicate entry when writing index: %s",
315 sha1_to_hex(object->sha1));
317 kh_value(writer.bitmaps, hash_pos) = stored;
318 display_progress(writer.progress, writer.selected_nr - i);
321 bitmap_free(base);
322 stop_progress(&writer.progress);
324 compute_xor_offsets();
328 * Select the commits that will be bitmapped
330 static inline unsigned int next_commit_index(unsigned int idx)
332 static const unsigned int MIN_COMMITS = 100;
333 static const unsigned int MAX_COMMITS = 5000;
335 static const unsigned int MUST_REGION = 100;
336 static const unsigned int MIN_REGION = 20000;
338 unsigned int offset, next;
340 if (idx <= MUST_REGION)
341 return 0;
343 if (idx <= MIN_REGION) {
344 offset = idx - MUST_REGION;
345 return (offset < MIN_COMMITS) ? offset : MIN_COMMITS;
348 offset = idx - MIN_REGION;
349 next = (offset < MAX_COMMITS) ? offset : MAX_COMMITS;
351 return (next > MIN_COMMITS) ? next : MIN_COMMITS;
354 static int date_compare(const void *_a, const void *_b)
356 struct commit *a = *(struct commit **)_a;
357 struct commit *b = *(struct commit **)_b;
358 return (long)b->date - (long)a->date;
361 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack)
363 if (prepare_bitmap_git() < 0)
364 return;
366 writer.reused = kh_init_sha1();
367 rebuild_existing_bitmaps(to_pack, writer.reused, writer.show_progress);
370 static struct ewah_bitmap *find_reused_bitmap(const unsigned char *sha1)
372 khiter_t hash_pos;
374 if (!writer.reused)
375 return NULL;
377 hash_pos = kh_get_sha1(writer.reused, sha1);
378 if (hash_pos >= kh_end(writer.reused))
379 return NULL;
381 return kh_value(writer.reused, hash_pos);
384 void bitmap_writer_select_commits(struct commit **indexed_commits,
385 unsigned int indexed_commits_nr,
386 int max_bitmaps)
388 unsigned int i = 0, j, next;
390 qsort(indexed_commits, indexed_commits_nr, sizeof(indexed_commits[0]),
391 date_compare);
393 if (writer.show_progress)
394 writer.progress = start_progress("Selecting bitmap commits", 0);
396 if (indexed_commits_nr < 100) {
397 for (i = 0; i < indexed_commits_nr; ++i)
398 push_bitmapped_commit(indexed_commits[i], NULL);
399 return;
402 for (;;) {
403 struct ewah_bitmap *reused_bitmap = NULL;
404 struct commit *chosen = NULL;
406 next = next_commit_index(i);
408 if (i + next >= indexed_commits_nr)
409 break;
411 if (max_bitmaps > 0 && writer.selected_nr >= max_bitmaps) {
412 writer.selected_nr = max_bitmaps;
413 break;
416 if (next == 0) {
417 chosen = indexed_commits[i];
418 reused_bitmap = find_reused_bitmap(chosen->object.sha1);
419 } else {
420 chosen = indexed_commits[i + next];
422 for (j = 0; j <= next; ++j) {
423 struct commit *cm = indexed_commits[i + j];
425 reused_bitmap = find_reused_bitmap(cm->object.sha1);
426 if (reused_bitmap || (cm->object.flags & NEEDS_BITMAP) != 0) {
427 chosen = cm;
428 break;
431 if (cm->parents && cm->parents->next)
432 chosen = cm;
436 push_bitmapped_commit(chosen, reused_bitmap);
438 i += next + 1;
439 display_progress(writer.progress, i);
442 stop_progress(&writer.progress);
446 static int sha1write_ewah_helper(void *f, const void *buf, size_t len)
448 /* sha1write will die on error */
449 sha1write(f, buf, len);
450 return len;
454 * Write the bitmap index to disk
456 static inline void dump_bitmap(struct sha1file *f, struct ewah_bitmap *bitmap)
458 if (ewah_serialize_to(bitmap, sha1write_ewah_helper, f) < 0)
459 die("Failed to write bitmap index");
462 static const unsigned char *sha1_access(size_t pos, void *table)
464 struct pack_idx_entry **index = table;
465 return index[pos]->sha1;
468 static void write_selected_commits_v1(struct sha1file *f,
469 struct pack_idx_entry **index,
470 uint32_t index_nr)
472 int i;
474 for (i = 0; i < writer.selected_nr; ++i) {
475 struct bitmapped_commit *stored = &writer.selected[i];
476 struct bitmap_disk_entry on_disk;
478 int commit_pos =
479 sha1_pos(stored->commit->object.sha1, index, index_nr, sha1_access);
481 if (commit_pos < 0)
482 die("BUG: trying to write commit not in index");
484 on_disk.object_pos = htonl(commit_pos);
485 on_disk.xor_offset = stored->xor_offset;
486 on_disk.flags = stored->flags;
488 sha1write(f, &on_disk, sizeof(on_disk));
489 dump_bitmap(f, stored->write_as);
493 static void write_hash_cache(struct sha1file *f,
494 struct pack_idx_entry **index,
495 uint32_t index_nr)
497 uint32_t i;
499 for (i = 0; i < index_nr; ++i) {
500 struct object_entry *entry = (struct object_entry *)index[i];
501 uint32_t hash_value = htonl(entry->hash);
502 sha1write(f, &hash_value, sizeof(hash_value));
506 void bitmap_writer_set_checksum(unsigned char *sha1)
508 hashcpy(writer.pack_checksum, sha1);
511 void bitmap_writer_finish(struct pack_idx_entry **index,
512 uint32_t index_nr,
513 const char *filename,
514 uint16_t options)
516 static char tmp_file[PATH_MAX];
517 static uint16_t default_version = 1;
518 static uint16_t flags = BITMAP_OPT_FULL_DAG;
519 struct sha1file *f;
521 struct bitmap_disk_header header;
523 int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
525 if (fd < 0)
526 die_errno("unable to create '%s'", tmp_file);
527 f = sha1fd(fd, tmp_file);
529 memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
530 header.version = htons(default_version);
531 header.options = htons(flags | options);
532 header.entry_count = htonl(writer.selected_nr);
533 memcpy(header.checksum, writer.pack_checksum, 20);
535 sha1write(f, &header, sizeof(header));
536 dump_bitmap(f, writer.commits);
537 dump_bitmap(f, writer.trees);
538 dump_bitmap(f, writer.blobs);
539 dump_bitmap(f, writer.tags);
540 write_selected_commits_v1(f, index, index_nr);
542 if (options & BITMAP_OPT_HASH_CACHE)
543 write_hash_cache(f, index, index_nr);
545 sha1close(f, NULL, CSUM_FSYNC);
547 if (adjust_shared_perm(tmp_file))
548 die_errno("unable to make temporary bitmap file readable");
550 if (rename(tmp_file, filename))
551 die_errno("unable to rename temporary bitmap file to '%s'", filename);