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#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 "commit-graph.h"
24#include "packfile.h"
25#include "object-store.h"
26#include "pack.h"
27#include "pack-objects.h"
28#include "blob.h"
29#include "tree.h"
30#define FAILED_RUN "failed to run %s"
32static const char * const builtin_gc_usage[] = {
34 N_("git gc [<options>]"),
35 NULL
36};
37static int pack_refs = 1;
39static int prune_reflogs = 1;
40static int aggressive_depth = 50;
41static int aggressive_window = 250;
42static int gc_auto_threshold = 6700;
43static int gc_auto_pack_limit = 50;
44static int gc_write_commit_graph;
45static int detach_auto = 1;
46static timestamp_t gc_log_expire_time;
47static const char *gc_log_expire = "1.day.ago";
48static const char *prune_expire = "2.weeks.ago";
49static const char *prune_worktrees_expire = "3.months.ago";
50static unsigned long big_pack_threshold;
51static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
52static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
54static struct argv_array reflog = ARGV_ARRAY_INIT;
55static struct argv_array repack = ARGV_ARRAY_INIT;
56static struct argv_array prune = ARGV_ARRAY_INIT;
57static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
58static struct argv_array rerere = ARGV_ARRAY_INIT;
59static struct tempfile *pidfile;
61static struct lock_file log_lock;
62static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
64static void clean_pack_garbage(void)
66{
67 int i;
68 for (i = 0; i < pack_garbage.nr; i++)
69 unlink_or_warn(pack_garbage.items[i].string);
70 string_list_clear(&pack_garbage, 0);
71}
72static void report_pack_garbage(unsigned seen_bits, const char *path)
74{
75 if (seen_bits == PACKDIR_FILE_IDX)
76 string_list_append(&pack_garbage, path);
77}
78static void process_log_file(void)
80{
81 struct stat st;
82 if (fstat(get_lock_file_fd(&log_lock), &st)) {
83 /*
84 * Perhaps there was an i/o error or another
85 * unlikely situation. Try to make a note of
86 * this in gc.log along with any existing
87 * messages.
88 */
89 int saved_errno = errno;
90 fprintf(stderr, _("Failed to fstat %s: %s"),
91 get_tempfile_path(log_lock.tempfile),
92 strerror(saved_errno));
93 fflush(stderr);
94 commit_lock_file(&log_lock);
95 errno = saved_errno;
96 } else if (st.st_size) {
97 /* There was some error recorded in the lock file */
98 commit_lock_file(&log_lock);
99 } else {
100 /* No error, clean up any old gc.log */
101 unlink(git_path("gc.log"));
102 rollback_lock_file(&log_lock);
103 }
104}
105static void process_log_file_at_exit(void)
107{
108 fflush(stderr);
109 process_log_file();
110}
111static void process_log_file_on_signal(int signo)
113{
114 process_log_file();
115 sigchain_pop(signo);
116 raise(signo);
117}
118static void gc_config(void)
120{
121 const char *value;
122 if (!git_config_get_value("gc.packrefs", &value)) {
124 if (value && !strcmp(value, "notbare"))
125 pack_refs = -1;
126 else
127 pack_refs = git_config_bool("gc.packrefs", value);
128 }
129 git_config_get_int("gc.aggressivewindow", &aggressive_window);
131 git_config_get_int("gc.aggressivedepth", &aggressive_depth);
132 git_config_get_int("gc.auto", &gc_auto_threshold);
133 git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
134 git_config_get_bool("gc.writecommitgraph", &gc_write_commit_graph);
135 git_config_get_bool("gc.autodetach", &detach_auto);
136 git_config_get_expiry("gc.pruneexpire", &prune_expire);
137 git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
138 git_config_get_expiry("gc.logexpiry", &gc_log_expire);
139 git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
141 git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
142 git_config(git_default_config, NULL);
144}
145static int too_many_loose_objects(void)
147{
148 /*
149 * Quickly check if a "gc" is needed, by estimating how
150 * many loose objects there are. Because SHA-1 is evenly
151 * distributed, we can check only one and get a reasonable
152 * estimate.
153 */
154 DIR *dir;
155 struct dirent *ent;
156 int auto_threshold;
157 int num_loose = 0;
158 int needed = 0;
159 if (gc_auto_threshold <= 0)
161 return 0;
162 dir = opendir(git_path("objects/17"));
164 if (!dir)
165 return 0;
166 auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
168 while ((ent = readdir(dir)) != NULL) {
169 if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
170 ent->d_name[38] != '\0')
171 continue;
172 if (++num_loose > auto_threshold) {
173 needed = 1;
174 break;
175 }
176 }
177 closedir(dir);
178 return needed;
179}
180static struct packed_git *find_base_packs(struct string_list *packs,
182 unsigned long limit)
183{
184 struct packed_git *p, *base = NULL;
185 for (p = get_all_packs(the_repository); p; p = p->next) {
187 if (!p->pack_local)
188 continue;
189 if (limit) {
190 if (p->pack_size >= limit)
191 string_list_append(packs, p->pack_name);
192 } else if (!base || base->pack_size < p->pack_size) {
193 base = p;
194 }
195 }
196 if (base)
198 string_list_append(packs, base->pack_name);
199 return base;
201}
202static int too_many_packs(void)
204{
205 struct packed_git *p;
206 int cnt;
207 if (gc_auto_pack_limit <= 0)
209 return 0;
210 for (cnt = 0, p = get_all_packs(the_repository); p; p = p->next) {
212 if (!p->pack_local)
213 continue;
214 if (p->pack_keep)
215 continue;
216 /*
217 * Perhaps check the size of the pack and count only
218 * very small ones here?
219 */
220 cnt++;
221 }
222 return gc_auto_pack_limit < cnt;
223}
224static uint64_t total_ram(void)
226{
227#if defined(HAVE_SYSINFO)
228 struct sysinfo si;
229 if (!sysinfo(&si))
231 return si.totalram;
232#elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
233 int64_t physical_memory;
234 int mib[2];
235 size_t length;
236 mib[0] = CTL_HW;
238# if defined(HW_MEMSIZE)
239 mib[1] = HW_MEMSIZE;
240# else
241 mib[1] = HW_PHYSMEM;
242# endif
243 length = sizeof(int64_t);
244 if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
245 return physical_memory;
246#elif defined(GIT_WINDOWS_NATIVE)
247 MEMORYSTATUSEX memInfo;
248 memInfo.dwLength = sizeof(MEMORYSTATUSEX);
250 if (GlobalMemoryStatusEx(&memInfo))
251 return memInfo.ullTotalPhys;
252#endif
253 return 0;
254}
255static uint64_t estimate_repack_memory(struct packed_git *pack)
257{
258 unsigned long nr_objects = approximate_object_count();
259 size_t os_cache, heap;
260 if (!pack || !nr_objects)
262 return 0;
263 /*
265 * First we have to scan through at least one pack.
266 * Assume enough room in OS file cache to keep the entire pack
267 * or we may accidentally evict data of other processes from
268 * the cache.
269 */
270 os_cache = pack->pack_size + pack->index_size;
271 /* then pack-objects needs lots more for book keeping */
272 heap = sizeof(struct object_entry) * nr_objects;
273 /*
274 * internal rev-list --all --objects takes up some memory too,
275 * let's say half of it is for blobs
276 */
277 heap += sizeof(struct blob) * nr_objects / 2;
278 /*
279 * and the other half is for trees (commits and tags are
280 * usually insignificant)
281 */
282 heap += sizeof(struct tree) * nr_objects / 2;
283 /* and then obj_hash[], underestimated in fact */
284 heap += sizeof(struct object *) * nr_objects;
285 /* revindex is used also */
286 heap += sizeof(struct revindex_entry) * nr_objects;
287 /*
288 * read_sha1_file() (either at delta calculation phase, or
289 * writing phase) also fills up the delta base cache
290 */
291 heap += delta_base_cache_limit;
292 /* and of course pack-objects has its own delta cache */
293 heap += max_delta_cache_size;
294 return os_cache + heap;
296}
297static int keep_one_pack(struct string_list_item *item, void *data)
299{
300 argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string));
301 return 0;
302}
303static void add_repack_all_option(struct string_list *keep_pack)
305{
306 if (prune_expire && !strcmp(prune_expire, "now"))
307 argv_array_push(&repack, "-a");
308 else {
309 argv_array_push(&repack, "-A");
310 if (prune_expire)
311 argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
312 }
313 if (keep_pack)
315 for_each_string_list(keep_pack, keep_one_pack, NULL);
316}
317static void add_repack_incremental_option(void)
319{
320 argv_array_push(&repack, "--no-write-bitmap-index");
321}
322static int need_to_gc(void)
324{
325 /*
326 * Setting gc.auto to 0 or negative can disable the
327 * automatic gc.
328 */
329 if (gc_auto_threshold <= 0)
330 return 0;
331 /*
333 * If there are too many loose objects, but not too many
334 * packs, we run "repack -d -l". If there are too many packs,
335 * we run "repack -A -d -l". Otherwise we tell the caller
336 * there is no need.
337 */
338 if (too_many_packs()) {
339 struct string_list keep_pack = STRING_LIST_INIT_NODUP;
340 if (big_pack_threshold) {
342 find_base_packs(&keep_pack, big_pack_threshold);
343 if (keep_pack.nr >= gc_auto_pack_limit) {
344 big_pack_threshold = 0;
345 string_list_clear(&keep_pack, 0);
346 find_base_packs(&keep_pack, 0);
347 }
348 } else {
349 struct packed_git *p = find_base_packs(&keep_pack, 0);
350 uint64_t mem_have, mem_want;
351 mem_have = total_ram();
353 mem_want = estimate_repack_memory(p);
354 /*
356 * Only allow 1/2 of memory for pack-objects, leave
357 * the rest for the OS and other processes in the
358 * system.
359 */
360 if (!mem_have || mem_want < mem_have / 2)
361 string_list_clear(&keep_pack, 0);
362 }
363 add_repack_all_option(&keep_pack);
365 string_list_clear(&keep_pack, 0);
366 } else if (too_many_loose_objects())
367 add_repack_incremental_option();
368 else
369 return 0;
370 if (run_hook_le(NULL, "pre-auto-gc", NULL))
372 return 0;
373 return 1;
374}
375/* return NULL on success, else hostname running the gc */
377static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
378{
379 struct lock_file lock = LOCK_INIT;
380 char my_host[HOST_NAME_MAX + 1];
381 struct strbuf sb = STRBUF_INIT;
382 struct stat st;
383 uintmax_t pid;
384 FILE *fp;
385 int fd;
386 char *pidfile_path;
387 if (is_tempfile_active(pidfile))
389 /* already locked */
390 return NULL;
391 if (xgethostname(my_host, sizeof(my_host)))
393 xsnprintf(my_host, sizeof(my_host), "unknown");
394 pidfile_path = git_pathdup("gc.pid");
396 fd = hold_lock_file_for_update(&lock, pidfile_path,
397 LOCK_DIE_ON_ERROR);
398 if (!force) {
399 static char locking_host[HOST_NAME_MAX + 1];
400 static char *scan_fmt;
401 int should_exit;
402 if (!scan_fmt)
404 scan_fmt = xstrfmt("%s %%%ds", "%"SCNuMAX, HOST_NAME_MAX);
405 fp = fopen(pidfile_path, "r");
406 memset(locking_host, 0, sizeof(locking_host));
407 should_exit =
408 fp != NULL &&
409 !fstat(fileno(fp), &st) &&
410 /*
411 * 12 hour limit is very generous as gc should
412 * never take that long. On the other hand we
413 * don't really need a strict limit here,
414 * running gc --auto one day late is not a big
415 * problem. --force can be used in manual gc
416 * after the user verifies that no gc is
417 * running.
418 */
419 time(NULL) - st.st_mtime <= 12 * 3600 &&
420 fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
421 /* be gentle to concurrent "gc" on remote hosts */
422 (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
423 if (fp != NULL)
424 fclose(fp);
425 if (should_exit) {
426 if (fd >= 0)
427 rollback_lock_file(&lock);
428 *ret_pid = pid;
429 free(pidfile_path);
430 return locking_host;
431 }
432 }
433 strbuf_addf(&sb, "%"PRIuMAX" %s",
435 (uintmax_t) getpid(), my_host);
436 write_in_full(fd, sb.buf, sb.len);
437 strbuf_release(&sb);
438 commit_lock_file(&lock);
439 pidfile = register_tempfile(pidfile_path);
440 free(pidfile_path);
441 return NULL;
442}
443/*
445 * Returns 0 if there was no previous error and gc can proceed, 1 if
446 * gc should not proceed due to an error in the last run. Prints a
447 * message and returns -1 if an error occured while reading gc.log
448 */
449static int report_last_gc_error(void)
450{
451 struct strbuf sb = STRBUF_INIT;
452 int ret = 0;
453 ssize_t len;
454 struct stat st;
455 char *gc_log_path = git_pathdup("gc.log");
456 if (stat(gc_log_path, &st)) {
458 if (errno == ENOENT)
459 goto done;
460 ret = error_errno(_("cannot stat '%s'"), gc_log_path);
462 goto done;
463 }
464 if (st.st_mtime < gc_log_expire_time)
466 goto done;
467 len = strbuf_read_file(&sb, gc_log_path, 0);
469 if (len < 0)
470 ret = error_errno(_("cannot read '%s'"), gc_log_path);
471 else if (len > 0) {
472 /*
473 * A previous gc failed. Report the error, and don't
474 * bother with an automatic gc run since it is likely
475 * to fail in the same way.
476 */
477 warning(_("The last gc run reported the following. "
478 "Please correct the root cause\n"
479 "and remove %s.\n"
480 "Automatic cleanup will not be performed "
481 "until the file is removed.\n\n"
482 "%s"),
483 gc_log_path, sb.buf);
484 ret = 1;
485 }
486 strbuf_release(&sb);
487done:
488 free(gc_log_path);
489 return ret;
490}
491static void gc_before_repack(void)
493{
494 if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
495 die(FAILED_RUN, pack_refs_cmd.argv[0]);
496 if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
498 die(FAILED_RUN, reflog.argv[0]);
499 pack_refs = 0;
501 prune_reflogs = 0;
502}
503int cmd_gc(int argc, const char **argv, const char *prefix)
505{
506 int aggressive = 0;
507 int auto_gc = 0;
508 int quiet = 0;
509 int force = 0;
510 const char *name;
511 pid_t pid;
512 int daemonized = 0;
513 int keep_base_pack = -1;
514 timestamp_t dummy;
515 struct option builtin_gc_options[] = {
517 OPT__QUIET(&quiet, N_("suppress progress reporting")),
518 { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
519 N_("prune unreferenced objects"),
520 PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
521 OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
522 OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"),
523 PARSE_OPT_NOCOMPLETE),
524 OPT_BOOL_F(0, "force", &force,
525 N_("force running gc even if there may be another gc running"),
526 PARSE_OPT_NOCOMPLETE),
527 OPT_BOOL(0, "keep-largest-pack", &keep_base_pack,
528 N_("repack all other packs except the largest pack")),
529 OPT_END()
530 };
531 if (argc == 2 && !strcmp(argv[1], "-h"))
533 usage_with_options(builtin_gc_usage, builtin_gc_options);
534 argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
536 argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
537 argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
538 argv_array_pushl(&prune, "prune", "--expire", NULL);
539 argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
540 argv_array_pushl(&rerere, "rerere", "gc", NULL);
541 /* default expiry time, overwritten in gc_config */
543 gc_config();
544 if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
545 die(_("failed to parse gc.logexpiry value %s"), gc_log_expire);
546 if (pack_refs < 0)
548 pack_refs = !is_bare_repository();
549 argc = parse_options(argc, argv, prefix, builtin_gc_options,
551 builtin_gc_usage, 0);
552 if (argc > 0)
553 usage_with_options(builtin_gc_usage, builtin_gc_options);
554 if (prune_expire && parse_expiry_date(prune_expire, &dummy))
556 die(_("failed to parse prune expiry value %s"), prune_expire);
557 if (aggressive) {
559 argv_array_push(&repack, "-f");
560 if (aggressive_depth > 0)
561 argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
562 if (aggressive_window > 0)
563 argv_array_pushf(&repack, "--window=%d", aggressive_window);
564 }
565 if (quiet)
566 argv_array_push(&repack, "-q");
567 if (auto_gc) {
569 /*
570 * Auto-gc should be least intrusive as possible.
571 */
572 if (!need_to_gc())
573 return 0;
574 if (!quiet) {
575 if (detach_auto)
576 fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
577 else
578 fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
579 fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
580 }
581 if (detach_auto) {
582 int ret = report_last_gc_error();
583 if (ret < 0)
584 /* an I/O error occured, already reported */
585 exit(128);
586 if (ret == 1)
587 /* Last gc --auto failed. Skip this one. */
588 return 0;
589 if (lock_repo_for_gc(force, &pid))
591 return 0;
592 gc_before_repack(); /* dies on failure */
593 delete_tempfile(&pidfile);
594 /*
596 * failure to daemonize is ok, we'll continue
597 * in foreground
598 */
599 daemonized = !daemonize();
600 }
601 } else {
602 struct string_list keep_pack = STRING_LIST_INIT_NODUP;
603 if (keep_base_pack != -1) {
605 if (keep_base_pack)
606 find_base_packs(&keep_pack, 0);
607 } else if (big_pack_threshold) {
608 find_base_packs(&keep_pack, big_pack_threshold);
609 }
610 add_repack_all_option(&keep_pack);
612 string_list_clear(&keep_pack, 0);
613 }
614 name = lock_repo_for_gc(force, &pid);
616 if (name) {
617 if (auto_gc)
618 return 0; /* be quiet on --auto */
619 die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
620 name, (uintmax_t)pid);
621 }
622 if (daemonized) {
624 hold_lock_file_for_update(&log_lock,
625 git_path("gc.log"),
626 LOCK_DIE_ON_ERROR);
627 dup2(get_lock_file_fd(&log_lock), 2);
628 sigchain_push_common(process_log_file_on_signal);
629 atexit(process_log_file_at_exit);
630 }
631 gc_before_repack();
633 if (!repository_format_precious_objects) {
635 close_all_packs(the_repository->objects);
636 if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
637 die(FAILED_RUN, repack.argv[0]);
638 if (prune_expire) {
640 argv_array_push(&prune, prune_expire);
641 if (quiet)
642 argv_array_push(&prune, "--no-progress");
643 if (repository_format_partial_clone)
644 argv_array_push(&prune,
645 "--exclude-promisor-objects");
646 if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
647 die(FAILED_RUN, prune.argv[0]);
648 }
649 }
650 if (prune_worktrees_expire) {
652 argv_array_push(&prune_worktrees, prune_worktrees_expire);
653 if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
654 die(FAILED_RUN, prune_worktrees.argv[0]);
655 }
656 if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
658 die(FAILED_RUN, rerere.argv[0]);
659 report_garbage = report_pack_garbage;
661 reprepare_packed_git(the_repository);
662 if (pack_garbage.nr > 0)
663 clean_pack_garbage();
664 if (gc_write_commit_graph)
666 write_commit_graph_reachable(get_object_directory(), 0,
667 !quiet && !daemonized);
668 if (auto_gc && too_many_loose_objects())
670 warning(_("There are too many unreachable loose objects; "
671 "run 'git prune' to remove them."));
672 if (!daemonized)
674 unlink(git_path("gc.log"));
675 return 0;
677}