2 * git gc builtin command
4 * Cleanup unreachable files and optimize the repository.
6 * Copyright (c) 2007 James Bowes
8 * Based on git-gc.sh, which is
10 * Copyright (c) 2006 Shawn O. Pearce
14 #include "repository.h"
18 #include "parse-options.h"
19 #include "run-command.h"
21 #include "argv-array.h"
23 #include "commit-graph.h"
25 #include "object-store.h"
27 #include "pack-objects.h"
31 #define FAILED_RUN "failed to run %s"
33 static const char * const builtin_gc_usage
[] = {
34 N_("git gc [<options>]"),
38 static int pack_refs
= 1;
39 static int prune_reflogs
= 1;
40 static int aggressive_depth
= 50;
41 static int aggressive_window
= 250;
42 static int gc_auto_threshold
= 6700;
43 static int gc_auto_pack_limit
= 50;
44 static int gc_write_commit_graph
;
45 static int detach_auto
= 1;
46 static timestamp_t gc_log_expire_time
;
47 static const char *gc_log_expire
= "1.day.ago";
48 static const char *prune_expire
= "2.weeks.ago";
49 static const char *prune_worktrees_expire
= "3.months.ago";
50 static unsigned long big_pack_threshold
;
51 static unsigned long max_delta_cache_size
= DEFAULT_DELTA_CACHE_SIZE
;
53 static struct argv_array pack_refs_cmd
= ARGV_ARRAY_INIT
;
54 static struct argv_array reflog
= ARGV_ARRAY_INIT
;
55 static struct argv_array repack
= ARGV_ARRAY_INIT
;
56 static struct argv_array prune
= ARGV_ARRAY_INIT
;
57 static struct argv_array prune_worktrees
= ARGV_ARRAY_INIT
;
58 static struct argv_array rerere
= ARGV_ARRAY_INIT
;
60 static struct tempfile
*pidfile
;
61 static struct lock_file log_lock
;
63 static struct string_list pack_garbage
= STRING_LIST_INIT_DUP
;
65 static void clean_pack_garbage(void)
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);
73 static void report_pack_garbage(unsigned seen_bits
, const char *path
)
75 if (seen_bits
== PACKDIR_FILE_IDX
)
76 string_list_append(&pack_garbage
, path
);
79 static void process_log_file(void)
82 if (fstat(get_lock_file_fd(&log_lock
), &st
)) {
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
89 int saved_errno
= errno
;
90 fprintf(stderr
, _("Failed to fstat %s: %s"),
91 get_tempfile_path(log_lock
.tempfile
),
92 strerror(saved_errno
));
94 commit_lock_file(&log_lock
);
96 } else if (st
.st_size
) {
97 /* There was some error recorded in the lock file */
98 commit_lock_file(&log_lock
);
100 /* No error, clean up any old gc.log */
101 unlink(git_path("gc.log"));
102 rollback_lock_file(&log_lock
);
106 static void process_log_file_at_exit(void)
112 static void process_log_file_on_signal(int signo
)
119 static void gc_config(void)
123 if (!git_config_get_value("gc.packrefs", &value
)) {
124 if (value
&& !strcmp(value
, "notbare"))
127 pack_refs
= git_config_bool("gc.packrefs", value
);
130 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
);
140 git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold
);
141 git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size
);
143 git_config(git_default_config
, NULL
);
146 static int too_many_loose_objects(void)
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
160 if (gc_auto_threshold
<= 0)
163 dir
= opendir(git_path("objects/17"));
167 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')
172 if (++num_loose
> auto_threshold
) {
181 static struct packed_git
*find_base_packs(struct string_list
*packs
,
184 struct packed_git
*p
, *base
= NULL
;
186 for (p
= get_all_packs(the_repository
); p
; p
= p
->next
) {
190 if (p
->pack_size
>= limit
)
191 string_list_append(packs
, p
->pack_name
);
192 } else if (!base
|| base
->pack_size
< p
->pack_size
) {
198 string_list_append(packs
, base
->pack_name
);
203 static int too_many_packs(void)
205 struct packed_git
*p
;
208 if (gc_auto_pack_limit
<= 0)
211 for (cnt
= 0, p
= get_all_packs(the_repository
); p
; p
= p
->next
) {
217 * Perhaps check the size of the pack and count only
218 * very small ones here?
222 return gc_auto_pack_limit
< cnt
;
225 static uint64_t total_ram(void)
227 #if defined(HAVE_SYSINFO)
232 #elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
233 int64_t physical_memory
;
238 # if defined(HW_MEMSIZE)
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
;
249 memInfo
.dwLength
= sizeof(MEMORYSTATUSEX
);
250 if (GlobalMemoryStatusEx(&memInfo
))
251 return memInfo
.ullTotalPhys
;
256 static uint64_t estimate_repack_memory(struct packed_git
*pack
)
258 unsigned long nr_objects
= approximate_object_count();
259 size_t os_cache
, heap
;
261 if (!pack
|| !nr_objects
)
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
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
;
274 * internal rev-list --all --objects takes up some memory too,
275 * let's say half of it is for blobs
277 heap
+= sizeof(struct blob
) * nr_objects
/ 2;
279 * and the other half is for trees (commits and tags are
280 * usually insignificant)
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
;
288 * read_sha1_file() (either at delta calculation phase, or
289 * writing phase) also fills up the delta base cache
291 heap
+= delta_base_cache_limit
;
292 /* and of course pack-objects has its own delta cache */
293 heap
+= max_delta_cache_size
;
295 return os_cache
+ heap
;
298 static int keep_one_pack(struct string_list_item
*item
, void *data
)
300 argv_array_pushf(&repack
, "--keep-pack=%s", basename(item
->string
));
304 static void add_repack_all_option(struct string_list
*keep_pack
)
306 if (prune_expire
&& !strcmp(prune_expire
, "now"))
307 argv_array_push(&repack
, "-a");
309 argv_array_push(&repack
, "-A");
311 argv_array_pushf(&repack
, "--unpack-unreachable=%s", prune_expire
);
315 for_each_string_list(keep_pack
, keep_one_pack
, NULL
);
318 static void add_repack_incremental_option(void)
320 argv_array_push(&repack
, "--no-write-bitmap-index");
323 static int need_to_gc(void)
326 * Setting gc.auto to 0 or negative can disable the
329 if (gc_auto_threshold
<= 0)
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
338 if (too_many_packs()) {
339 struct string_list keep_pack
= STRING_LIST_INIT_NODUP
;
341 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);
349 struct packed_git
*p
= find_base_packs(&keep_pack
, 0);
350 uint64_t mem_have
, mem_want
;
352 mem_have
= total_ram();
353 mem_want
= estimate_repack_memory(p
);
356 * Only allow 1/2 of memory for pack-objects, leave
357 * the rest for the OS and other processes in the
360 if (!mem_have
|| mem_want
< mem_have
/ 2)
361 string_list_clear(&keep_pack
, 0);
364 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();
371 if (run_hook_le(NULL
, "pre-auto-gc", NULL
))
376 /* return NULL on success, else hostname running the gc */
377 static const char *lock_repo_for_gc(int force
, pid_t
* ret_pid
)
379 struct lock_file lock
= LOCK_INIT
;
380 char my_host
[HOST_NAME_MAX
+ 1];
381 struct strbuf sb
= STRBUF_INIT
;
388 if (is_tempfile_active(pidfile
))
392 if (xgethostname(my_host
, sizeof(my_host
)))
393 xsnprintf(my_host
, sizeof(my_host
), "unknown");
395 pidfile_path
= git_pathdup("gc.pid");
396 fd
= hold_lock_file_for_update(&lock
, pidfile_path
,
399 static char locking_host
[HOST_NAME_MAX
+ 1];
400 static char *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
));
409 !fstat(fileno(fp
), &st
) &&
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
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
);
427 rollback_lock_file(&lock
);
434 strbuf_addf(&sb
, "%"PRIuMAX
" %s",
435 (uintmax_t) getpid(), my_host
);
436 write_in_full(fd
, sb
.buf
, sb
.len
);
438 commit_lock_file(&lock
);
439 pidfile
= register_tempfile(pidfile_path
);
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
449 static int report_last_gc_error(void)
451 struct strbuf sb
= STRBUF_INIT
;
455 char *gc_log_path
= git_pathdup("gc.log");
457 if (stat(gc_log_path
, &st
)) {
461 ret
= error_errno(_("cannot stat '%s'"), gc_log_path
);
465 if (st
.st_mtime
< gc_log_expire_time
)
468 len
= strbuf_read_file(&sb
, gc_log_path
, 0);
470 ret
= error_errno(_("cannot read '%s'"), gc_log_path
);
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.
477 warning(_("The last gc run reported the following. "
478 "Please correct the root cause\n"
480 "Automatic cleanup will not be performed "
481 "until the file is removed.\n\n"
483 gc_log_path
, sb
.buf
);
492 static void gc_before_repack(void)
494 if (pack_refs
&& run_command_v_opt(pack_refs_cmd
.argv
, RUN_GIT_CMD
))
495 die(FAILED_RUN
, pack_refs_cmd
.argv
[0]);
497 if (prune_reflogs
&& run_command_v_opt(reflog
.argv
, RUN_GIT_CMD
))
498 die(FAILED_RUN
, reflog
.argv
[0]);
504 int cmd_gc(int argc
, const char **argv
, const char *prefix
)
513 int keep_base_pack
= -1;
516 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")),
532 if (argc
== 2 && !strcmp(argv
[1], "-h"))
533 usage_with_options(builtin_gc_usage
, builtin_gc_options
);
535 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
);
542 /* default expiry time, overwritten in 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
);
548 pack_refs
= !is_bare_repository();
550 argc
= parse_options(argc
, argv
, prefix
, builtin_gc_options
,
551 builtin_gc_usage
, 0);
553 usage_with_options(builtin_gc_usage
, builtin_gc_options
);
555 if (prune_expire
&& parse_expiry_date(prune_expire
, &dummy
))
556 die(_("failed to parse prune expiry value %s"), prune_expire
);
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
);
566 argv_array_push(&repack
, "-q");
570 * Auto-gc should be least intrusive as possible.
576 fprintf(stderr
, _("Auto packing the repository in background for optimum performance.\n"));
578 fprintf(stderr
, _("Auto packing the repository for optimum performance.\n"));
579 fprintf(stderr
, _("See \"git help gc\" for manual housekeeping.\n"));
582 int ret
= report_last_gc_error();
584 /* an I/O error occured, already reported */
587 /* Last gc --auto failed. Skip this one. */
590 if (lock_repo_for_gc(force
, &pid
))
592 gc_before_repack(); /* dies on failure */
593 delete_tempfile(&pidfile
);
596 * failure to daemonize is ok, we'll continue
599 daemonized
= !daemonize();
602 struct string_list keep_pack
= STRING_LIST_INIT_NODUP
;
604 if (keep_base_pack
!= -1) {
606 find_base_packs(&keep_pack
, 0);
607 } else if (big_pack_threshold
) {
608 find_base_packs(&keep_pack
, big_pack_threshold
);
611 add_repack_all_option(&keep_pack
);
612 string_list_clear(&keep_pack
, 0);
615 name
= lock_repo_for_gc(force
, &pid
);
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
);
624 hold_lock_file_for_update(&log_lock
,
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
);
634 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]);
640 argv_array_push(&prune
, prune_expire
);
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]);
651 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]);
657 if (run_command_v_opt(rerere
.argv
, RUN_GIT_CMD
))
658 die(FAILED_RUN
, rerere
.argv
[0]);
660 report_garbage
= report_pack_garbage
;
661 reprepare_packed_git(the_repository
);
662 if (pack_garbage
.nr
> 0)
663 clean_pack_garbage();
665 if (gc_write_commit_graph
)
666 write_commit_graph_reachable(get_object_directory(), 0,
667 !quiet
&& !daemonized
);
669 if (auto_gc
&& too_many_loose_objects())
670 warning(_("There are too many unreachable loose objects; "
671 "run 'git prune' to remove them."));
674 unlink(git_path("gc.log"));