Merge branch 'bc/hash-independent-tests'
[git/git.git] / builtin / gc.c
1 /*
2 * git gc builtin command
3 *
4 * Cleanup unreachable files and optimize the repository.
5 *
6 * Copyright (c) 2007 James Bowes
7 *
8 * Based on git-gc.sh, which is
9 *
10 * Copyright (c) 2006 Shawn O. Pearce
11 */
12
13 #include "builtin.h"
14 #include "repository.h"
15 #include "config.h"
16 #include "tempfile.h"
17 #include "lockfile.h"
18 #include "parse-options.h"
19 #include "run-command.h"
20 #include "sigchain.h"
21 #include "argv-array.h"
22 #include "commit.h"
23 #include "packfile.h"
24 #include "object-store.h"
25 #include "pack.h"
26 #include "pack-objects.h"
27 #include "blob.h"
28 #include "tree.h"
29
30 #define FAILED_RUN "failed to run %s"
31
32 static const char * const builtin_gc_usage[] = {
33 N_("git gc [<options>]"),
34 NULL
35 };
36
37 static int pack_refs = 1;
38 static int prune_reflogs = 1;
39 static int aggressive_depth = 50;
40 static int aggressive_window = 250;
41 static int gc_auto_threshold = 6700;
42 static int gc_auto_pack_limit = 50;
43 static int detach_auto = 1;
44 static timestamp_t gc_log_expire_time;
45 static const char *gc_log_expire = "1.day.ago";
46 static const char *prune_expire = "2.weeks.ago";
47 static const char *prune_worktrees_expire = "3.months.ago";
48 static unsigned long big_pack_threshold;
49 static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
50
51 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
52 static struct argv_array reflog = ARGV_ARRAY_INIT;
53 static struct argv_array repack = ARGV_ARRAY_INIT;
54 static struct argv_array prune = ARGV_ARRAY_INIT;
55 static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
56 static struct argv_array rerere = ARGV_ARRAY_INIT;
57
58 static struct tempfile *pidfile;
59 static struct lock_file log_lock;
60
61 static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
62
63 static void clean_pack_garbage(void)
64 {
65 int i;
66 for (i = 0; i < pack_garbage.nr; i++)
67 unlink_or_warn(pack_garbage.items[i].string);
68 string_list_clear(&pack_garbage, 0);
69 }
70
71 static void report_pack_garbage(unsigned seen_bits, const char *path)
72 {
73 if (seen_bits == PACKDIR_FILE_IDX)
74 string_list_append(&pack_garbage, path);
75 }
76
77 static void process_log_file(void)
78 {
79 struct stat st;
80 if (fstat(get_lock_file_fd(&log_lock), &st)) {
81 /*
82 * Perhaps there was an i/o error or another
83 * unlikely situation. Try to make a note of
84 * this in gc.log along with any existing
85 * messages.
86 */
87 int saved_errno = errno;
88 fprintf(stderr, _("Failed to fstat %s: %s"),
89 get_tempfile_path(log_lock.tempfile),
90 strerror(saved_errno));
91 fflush(stderr);
92 commit_lock_file(&log_lock);
93 errno = saved_errno;
94 } else if (st.st_size) {
95 /* There was some error recorded in the lock file */
96 commit_lock_file(&log_lock);
97 } else {
98 /* No error, clean up any old gc.log */
99 unlink(git_path("gc.log"));
100 rollback_lock_file(&log_lock);
101 }
102 }
103
104 static void process_log_file_at_exit(void)
105 {
106 fflush(stderr);
107 process_log_file();
108 }
109
110 static void process_log_file_on_signal(int signo)
111 {
112 process_log_file();
113 sigchain_pop(signo);
114 raise(signo);
115 }
116
117 static void gc_config(void)
118 {
119 const char *value;
120
121 if (!git_config_get_value("gc.packrefs", &value)) {
122 if (value && !strcmp(value, "notbare"))
123 pack_refs = -1;
124 else
125 pack_refs = git_config_bool("gc.packrefs", value);
126 }
127
128 git_config_get_int("gc.aggressivewindow", &aggressive_window);
129 git_config_get_int("gc.aggressivedepth", &aggressive_depth);
130 git_config_get_int("gc.auto", &gc_auto_threshold);
131 git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
132 git_config_get_bool("gc.autodetach", &detach_auto);
133 git_config_get_expiry("gc.pruneexpire", &prune_expire);
134 git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
135 git_config_get_expiry("gc.logexpiry", &gc_log_expire);
136
137 git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
138 git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
139
140 git_config(git_default_config, NULL);
141 }
142
143 static int too_many_loose_objects(void)
144 {
145 /*
146 * Quickly check if a "gc" is needed, by estimating how
147 * many loose objects there are. Because SHA-1 is evenly
148 * distributed, we can check only one and get a reasonable
149 * estimate.
150 */
151 DIR *dir;
152 struct dirent *ent;
153 int auto_threshold;
154 int num_loose = 0;
155 int needed = 0;
156
157 if (gc_auto_threshold <= 0)
158 return 0;
159
160 dir = opendir(git_path("objects/17"));
161 if (!dir)
162 return 0;
163
164 auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
165 while ((ent = readdir(dir)) != NULL) {
166 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
167 ent->d_name[38] != '\0')
168 continue;
169 if (++num_loose > auto_threshold) {
170 needed = 1;
171 break;
172 }
173 }
174 closedir(dir);
175 return needed;
176 }
177
178 static struct packed_git *find_base_packs(struct string_list *packs,
179 unsigned long limit)
180 {
181 struct packed_git *p, *base = NULL;
182
183 for (p = get_packed_git(the_repository); p; p = p->next) {
184 if (!p->pack_local)
185 continue;
186 if (limit) {
187 if (p->pack_size >= limit)
188 string_list_append(packs, p->pack_name);
189 } else if (!base || base->pack_size < p->pack_size) {
190 base = p;
191 }
192 }
193
194 if (base)
195 string_list_append(packs, base->pack_name);
196
197 return base;
198 }
199
200 static int too_many_packs(void)
201 {
202 struct packed_git *p;
203 int cnt;
204
205 if (gc_auto_pack_limit <= 0)
206 return 0;
207
208 for (cnt = 0, p = get_packed_git(the_repository); p; p = p->next) {
209 if (!p->pack_local)
210 continue;
211 if (p->pack_keep)
212 continue;
213 /*
214 * Perhaps check the size of the pack and count only
215 * very small ones here?
216 */
217 cnt++;
218 }
219 return gc_auto_pack_limit < cnt;
220 }
221
222 static uint64_t total_ram(void)
223 {
224 #if defined(HAVE_SYSINFO)
225 struct sysinfo si;
226
227 if (!sysinfo(&si))
228 return si.totalram;
229 #elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
230 int64_t physical_memory;
231 int mib[2];
232 size_t length;
233
234 mib[0] = CTL_HW;
235 # if defined(HW_MEMSIZE)
236 mib[1] = HW_MEMSIZE;
237 # else
238 mib[1] = HW_PHYSMEM;
239 # endif
240 length = sizeof(int64_t);
241 if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
242 return physical_memory;
243 #elif defined(GIT_WINDOWS_NATIVE)
244 MEMORYSTATUSEX memInfo;
245
246 memInfo.dwLength = sizeof(MEMORYSTATUSEX);
247 if (GlobalMemoryStatusEx(&memInfo))
248 return memInfo.ullTotalPhys;
249 #endif
250 return 0;
251 }
252
253 static uint64_t estimate_repack_memory(struct packed_git *pack)
254 {
255 unsigned long nr_objects = approximate_object_count();
256 size_t os_cache, heap;
257
258 if (!pack || !nr_objects)
259 return 0;
260
261 /*
262 * First we have to scan through at least one pack.
263 * Assume enough room in OS file cache to keep the entire pack
264 * or we may accidentally evict data of other processes from
265 * the cache.
266 */
267 os_cache = pack->pack_size + pack->index_size;
268 /* then pack-objects needs lots more for book keeping */
269 heap = sizeof(struct object_entry) * nr_objects;
270 /*
271 * internal rev-list --all --objects takes up some memory too,
272 * let's say half of it is for blobs
273 */
274 heap += sizeof(struct blob) * nr_objects / 2;
275 /*
276 * and the other half is for trees (commits and tags are
277 * usually insignificant)
278 */
279 heap += sizeof(struct tree) * nr_objects / 2;
280 /* and then obj_hash[], underestimated in fact */
281 heap += sizeof(struct object *) * nr_objects;
282 /* revindex is used also */
283 heap += sizeof(struct revindex_entry) * nr_objects;
284 /*
285 * read_sha1_file() (either at delta calculation phase, or
286 * writing phase) also fills up the delta base cache
287 */
288 heap += delta_base_cache_limit;
289 /* and of course pack-objects has its own delta cache */
290 heap += max_delta_cache_size;
291
292 return os_cache + heap;
293 }
294
295 static int keep_one_pack(struct string_list_item *item, void *data)
296 {
297 argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string));
298 return 0;
299 }
300
301 static void add_repack_all_option(struct string_list *keep_pack)
302 {
303 if (prune_expire && !strcmp(prune_expire, "now"))
304 argv_array_push(&repack, "-a");
305 else {
306 argv_array_push(&repack, "-A");
307 if (prune_expire)
308 argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
309 }
310
311 if (keep_pack)
312 for_each_string_list(keep_pack, keep_one_pack, NULL);
313 }
314
315 static void add_repack_incremental_option(void)
316 {
317 argv_array_push(&repack, "--no-write-bitmap-index");
318 }
319
320 static int need_to_gc(void)
321 {
322 /*
323 * Setting gc.auto to 0 or negative can disable the
324 * automatic gc.
325 */
326 if (gc_auto_threshold <= 0)
327 return 0;
328
329 /*
330 * If there are too many loose objects, but not too many
331 * packs, we run "repack -d -l". If there are too many packs,
332 * we run "repack -A -d -l". Otherwise we tell the caller
333 * there is no need.
334 */
335 if (too_many_packs()) {
336 struct string_list keep_pack = STRING_LIST_INIT_NODUP;
337
338 if (big_pack_threshold) {
339 find_base_packs(&keep_pack, big_pack_threshold);
340 if (keep_pack.nr >= gc_auto_pack_limit) {
341 big_pack_threshold = 0;
342 string_list_clear(&keep_pack, 0);
343 find_base_packs(&keep_pack, 0);
344 }
345 } else {
346 struct packed_git *p = find_base_packs(&keep_pack, 0);
347 uint64_t mem_have, mem_want;
348
349 mem_have = total_ram();
350 mem_want = estimate_repack_memory(p);
351
352 /*
353 * Only allow 1/2 of memory for pack-objects, leave
354 * the rest for the OS and other processes in the
355 * system.
356 */
357 if (!mem_have || mem_want < mem_have / 2)
358 string_list_clear(&keep_pack, 0);
359 }
360
361 add_repack_all_option(&keep_pack);
362 string_list_clear(&keep_pack, 0);
363 } else if (too_many_loose_objects())
364 add_repack_incremental_option();
365 else
366 return 0;
367
368 if (run_hook_le(NULL, "pre-auto-gc", NULL))
369 return 0;
370 return 1;
371 }
372
373 /* return NULL on success, else hostname running the gc */
374 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
375 {
376 struct lock_file lock = LOCK_INIT;
377 char my_host[HOST_NAME_MAX + 1];
378 struct strbuf sb = STRBUF_INIT;
379 struct stat st;
380 uintmax_t pid;
381 FILE *fp;
382 int fd;
383 char *pidfile_path;
384
385 if (is_tempfile_active(pidfile))
386 /* already locked */
387 return NULL;
388
389 if (xgethostname(my_host, sizeof(my_host)))
390 xsnprintf(my_host, sizeof(my_host), "unknown");
391
392 pidfile_path = git_pathdup("gc.pid");
393 fd = hold_lock_file_for_update(&lock, pidfile_path,
394 LOCK_DIE_ON_ERROR);
395 if (!force) {
396 static char locking_host[HOST_NAME_MAX + 1];
397 static char *scan_fmt;
398 int should_exit;
399
400 if (!scan_fmt)
401 scan_fmt = xstrfmt("%s %%%ds", "%"SCNuMAX, HOST_NAME_MAX);
402 fp = fopen(pidfile_path, "r");
403 memset(locking_host, 0, sizeof(locking_host));
404 should_exit =
405 fp != NULL &&
406 !fstat(fileno(fp), &st) &&
407 /*
408 * 12 hour limit is very generous as gc should
409 * never take that long. On the other hand we
410 * don't really need a strict limit here,
411 * running gc --auto one day late is not a big
412 * problem. --force can be used in manual gc
413 * after the user verifies that no gc is
414 * running.
415 */
416 time(NULL) - st.st_mtime <= 12 * 3600 &&
417 fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
418 /* be gentle to concurrent "gc" on remote hosts */
419 (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
420 if (fp != NULL)
421 fclose(fp);
422 if (should_exit) {
423 if (fd >= 0)
424 rollback_lock_file(&lock);
425 *ret_pid = pid;
426 free(pidfile_path);
427 return locking_host;
428 }
429 }
430
431 strbuf_addf(&sb, "%"PRIuMAX" %s",
432 (uintmax_t) getpid(), my_host);
433 write_in_full(fd, sb.buf, sb.len);
434 strbuf_release(&sb);
435 commit_lock_file(&lock);
436 pidfile = register_tempfile(pidfile_path);
437 free(pidfile_path);
438 return NULL;
439 }
440
441 static int report_last_gc_error(void)
442 {
443 struct strbuf sb = STRBUF_INIT;
444 int ret = 0;
445 struct stat st;
446 char *gc_log_path = git_pathdup("gc.log");
447
448 if (stat(gc_log_path, &st)) {
449 if (errno == ENOENT)
450 goto done;
451
452 ret = error_errno(_("Can't stat %s"), gc_log_path);
453 goto done;
454 }
455
456 if (st.st_mtime < gc_log_expire_time)
457 goto done;
458
459 ret = strbuf_read_file(&sb, gc_log_path, 0);
460 if (ret > 0)
461 ret = error(_("The last gc run reported the following. "
462 "Please correct the root cause\n"
463 "and remove %s.\n"
464 "Automatic cleanup will not be performed "
465 "until the file is removed.\n\n"
466 "%s"),
467 gc_log_path, sb.buf);
468 strbuf_release(&sb);
469 done:
470 free(gc_log_path);
471 return ret;
472 }
473
474 static int gc_before_repack(void)
475 {
476 if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
477 return error(FAILED_RUN, pack_refs_cmd.argv[0]);
478
479 if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
480 return error(FAILED_RUN, reflog.argv[0]);
481
482 pack_refs = 0;
483 prune_reflogs = 0;
484 return 0;
485 }
486
487 int cmd_gc(int argc, const char **argv, const char *prefix)
488 {
489 int aggressive = 0;
490 int auto_gc = 0;
491 int quiet = 0;
492 int force = 0;
493 const char *name;
494 pid_t pid;
495 int daemonized = 0;
496 int keep_base_pack = -1;
497 timestamp_t dummy;
498
499 struct option builtin_gc_options[] = {
500 OPT__QUIET(&quiet, N_("suppress progress reporting")),
501 { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
502 N_("prune unreferenced objects"),
503 PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
504 OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
505 OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"),
506 PARSE_OPT_NOCOMPLETE),
507 OPT_BOOL_F(0, "force", &force,
508 N_("force running gc even if there may be another gc running"),
509 PARSE_OPT_NOCOMPLETE),
510 OPT_BOOL(0, "keep-largest-pack", &keep_base_pack,
511 N_("repack all other packs except the largest pack")),
512 OPT_END()
513 };
514
515 if (argc == 2 && !strcmp(argv[1], "-h"))
516 usage_with_options(builtin_gc_usage, builtin_gc_options);
517
518 argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
519 argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
520 argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
521 argv_array_pushl(&prune, "prune", "--expire", NULL);
522 argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
523 argv_array_pushl(&rerere, "rerere", "gc", NULL);
524
525 /* default expiry time, overwritten in gc_config */
526 gc_config();
527 if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
528 die(_("failed to parse gc.logexpiry value %s"), gc_log_expire);
529
530 if (pack_refs < 0)
531 pack_refs = !is_bare_repository();
532
533 argc = parse_options(argc, argv, prefix, builtin_gc_options,
534 builtin_gc_usage, 0);
535 if (argc > 0)
536 usage_with_options(builtin_gc_usage, builtin_gc_options);
537
538 if (prune_expire && parse_expiry_date(prune_expire, &dummy))
539 die(_("failed to parse prune expiry value %s"), prune_expire);
540
541 if (aggressive) {
542 argv_array_push(&repack, "-f");
543 if (aggressive_depth > 0)
544 argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
545 if (aggressive_window > 0)
546 argv_array_pushf(&repack, "--window=%d", aggressive_window);
547 }
548 if (quiet)
549 argv_array_push(&repack, "-q");
550
551 if (auto_gc) {
552 /*
553 * Auto-gc should be least intrusive as possible.
554 */
555 if (!need_to_gc())
556 return 0;
557 if (!quiet) {
558 if (detach_auto)
559 fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
560 else
561 fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
562 fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
563 }
564 if (detach_auto) {
565 if (report_last_gc_error())
566 return -1;
567
568 if (lock_repo_for_gc(force, &pid))
569 return 0;
570 if (gc_before_repack())
571 return -1;
572 delete_tempfile(&pidfile);
573
574 /*
575 * failure to daemonize is ok, we'll continue
576 * in foreground
577 */
578 daemonized = !daemonize();
579 }
580 } else {
581 struct string_list keep_pack = STRING_LIST_INIT_NODUP;
582
583 if (keep_base_pack != -1) {
584 if (keep_base_pack)
585 find_base_packs(&keep_pack, 0);
586 } else if (big_pack_threshold) {
587 find_base_packs(&keep_pack, big_pack_threshold);
588 }
589
590 add_repack_all_option(&keep_pack);
591 string_list_clear(&keep_pack, 0);
592 }
593
594 name = lock_repo_for_gc(force, &pid);
595 if (name) {
596 if (auto_gc)
597 return 0; /* be quiet on --auto */
598 die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
599 name, (uintmax_t)pid);
600 }
601
602 if (daemonized) {
603 hold_lock_file_for_update(&log_lock,
604 git_path("gc.log"),
605 LOCK_DIE_ON_ERROR);
606 dup2(get_lock_file_fd(&log_lock), 2);
607 sigchain_push_common(process_log_file_on_signal);
608 atexit(process_log_file_at_exit);
609 }
610
611 if (gc_before_repack())
612 return -1;
613
614 if (!repository_format_precious_objects) {
615 if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
616 return error(FAILED_RUN, repack.argv[0]);
617
618 if (prune_expire) {
619 argv_array_push(&prune, prune_expire);
620 if (quiet)
621 argv_array_push(&prune, "--no-progress");
622 if (repository_format_partial_clone)
623 argv_array_push(&prune,
624 "--exclude-promisor-objects");
625 if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
626 return error(FAILED_RUN, prune.argv[0]);
627 }
628 }
629
630 if (prune_worktrees_expire) {
631 argv_array_push(&prune_worktrees, prune_worktrees_expire);
632 if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
633 return error(FAILED_RUN, prune_worktrees.argv[0]);
634 }
635
636 if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
637 return error(FAILED_RUN, rerere.argv[0]);
638
639 report_garbage = report_pack_garbage;
640 reprepare_packed_git(the_repository);
641 if (pack_garbage.nr > 0)
642 clean_pack_garbage();
643
644 if (auto_gc && too_many_loose_objects())
645 warning(_("There are too many unreachable loose objects; "
646 "run 'git prune' to remove them."));
647
648 if (!daemonized)
649 unlink(git_path("gc.log"));
650
651 return 0;
652 }