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
159 const unsigned hexsz_loose
= the_hash_algo
->hexsz
- 2;
161 dir
= opendir(git_path("objects/17"));
165 auto_threshold
= DIV_ROUND_UP(gc_auto_threshold
, 256);
166 while ((ent
= readdir(dir
)) != NULL
) {
167 if (strspn(ent
->d_name
, "0123456789abcdef") != hexsz_loose
||
168 ent
->d_name
[hexsz_loose
] != '\0')
170 if (++num_loose
> auto_threshold
) {
179 static struct packed_git
*find_base_packs(struct string_list
*packs
,
182 struct packed_git
*p
, *base
= NULL
;
184 for (p
= get_all_packs(the_repository
); p
; p
= p
->next
) {
188 if (p
->pack_size
>= limit
)
189 string_list_append(packs
, p
->pack_name
);
190 } else if (!base
|| base
->pack_size
< p
->pack_size
) {
196 string_list_append(packs
, base
->pack_name
);
201 static int too_many_packs(void)
203 struct packed_git
*p
;
206 if (gc_auto_pack_limit
<= 0)
209 for (cnt
= 0, p
= get_all_packs(the_repository
); p
; p
= p
->next
) {
215 * Perhaps check the size of the pack and count only
216 * very small ones here?
220 return gc_auto_pack_limit
< cnt
;
223 static uint64_t total_ram(void)
225 #if defined(HAVE_SYSINFO)
230 #elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
231 int64_t physical_memory
;
236 # if defined(HW_MEMSIZE)
241 length
= sizeof(int64_t);
242 if (!sysctl(mib
, 2, &physical_memory
, &length
, NULL
, 0))
243 return physical_memory
;
244 #elif defined(GIT_WINDOWS_NATIVE)
245 MEMORYSTATUSEX memInfo
;
247 memInfo
.dwLength
= sizeof(MEMORYSTATUSEX
);
248 if (GlobalMemoryStatusEx(&memInfo
))
249 return memInfo
.ullTotalPhys
;
254 static uint64_t estimate_repack_memory(struct packed_git
*pack
)
256 unsigned long nr_objects
= approximate_object_count();
257 size_t os_cache
, heap
;
259 if (!pack
|| !nr_objects
)
263 * First we have to scan through at least one pack.
264 * Assume enough room in OS file cache to keep the entire pack
265 * or we may accidentally evict data of other processes from
268 os_cache
= pack
->pack_size
+ pack
->index_size
;
269 /* then pack-objects needs lots more for book keeping */
270 heap
= sizeof(struct object_entry
) * nr_objects
;
272 * internal rev-list --all --objects takes up some memory too,
273 * let's say half of it is for blobs
275 heap
+= sizeof(struct blob
) * nr_objects
/ 2;
277 * and the other half is for trees (commits and tags are
278 * usually insignificant)
280 heap
+= sizeof(struct tree
) * nr_objects
/ 2;
281 /* and then obj_hash[], underestimated in fact */
282 heap
+= sizeof(struct object
*) * nr_objects
;
283 /* revindex is used also */
284 heap
+= sizeof(struct revindex_entry
) * nr_objects
;
286 * read_sha1_file() (either at delta calculation phase, or
287 * writing phase) also fills up the delta base cache
289 heap
+= delta_base_cache_limit
;
290 /* and of course pack-objects has its own delta cache */
291 heap
+= max_delta_cache_size
;
293 return os_cache
+ heap
;
296 static int keep_one_pack(struct string_list_item
*item
, void *data
)
298 argv_array_pushf(&repack
, "--keep-pack=%s", basename(item
->string
));
302 static void add_repack_all_option(struct string_list
*keep_pack
)
304 if (prune_expire
&& !strcmp(prune_expire
, "now"))
305 argv_array_push(&repack
, "-a");
307 argv_array_push(&repack
, "-A");
309 argv_array_pushf(&repack
, "--unpack-unreachable=%s", prune_expire
);
313 for_each_string_list(keep_pack
, keep_one_pack
, NULL
);
316 static void add_repack_incremental_option(void)
318 argv_array_push(&repack
, "--no-write-bitmap-index");
321 static int need_to_gc(void)
324 * Setting gc.auto to 0 or negative can disable the
327 if (gc_auto_threshold
<= 0)
331 * If there are too many loose objects, but not too many
332 * packs, we run "repack -d -l". If there are too many packs,
333 * we run "repack -A -d -l". Otherwise we tell the caller
336 if (too_many_packs()) {
337 struct string_list keep_pack
= STRING_LIST_INIT_NODUP
;
339 if (big_pack_threshold
) {
340 find_base_packs(&keep_pack
, big_pack_threshold
);
341 if (keep_pack
.nr
>= gc_auto_pack_limit
) {
342 big_pack_threshold
= 0;
343 string_list_clear(&keep_pack
, 0);
344 find_base_packs(&keep_pack
, 0);
347 struct packed_git
*p
= find_base_packs(&keep_pack
, 0);
348 uint64_t mem_have
, mem_want
;
350 mem_have
= total_ram();
351 mem_want
= estimate_repack_memory(p
);
354 * Only allow 1/2 of memory for pack-objects, leave
355 * the rest for the OS and other processes in the
358 if (!mem_have
|| mem_want
< mem_have
/ 2)
359 string_list_clear(&keep_pack
, 0);
362 add_repack_all_option(&keep_pack
);
363 string_list_clear(&keep_pack
, 0);
364 } else if (too_many_loose_objects())
365 add_repack_incremental_option();
369 if (run_hook_le(NULL
, "pre-auto-gc", NULL
))
374 /* return NULL on success, else hostname running the gc */
375 static const char *lock_repo_for_gc(int force
, pid_t
* ret_pid
)
377 struct lock_file lock
= LOCK_INIT
;
378 char my_host
[HOST_NAME_MAX
+ 1];
379 struct strbuf sb
= STRBUF_INIT
;
386 if (is_tempfile_active(pidfile
))
390 if (xgethostname(my_host
, sizeof(my_host
)))
391 xsnprintf(my_host
, sizeof(my_host
), "unknown");
393 pidfile_path
= git_pathdup("gc.pid");
394 fd
= hold_lock_file_for_update(&lock
, pidfile_path
,
397 static char locking_host
[HOST_NAME_MAX
+ 1];
398 static char *scan_fmt
;
402 scan_fmt
= xstrfmt("%s %%%ds", "%"SCNuMAX
, HOST_NAME_MAX
);
403 fp
= fopen(pidfile_path
, "r");
404 memset(locking_host
, 0, sizeof(locking_host
));
407 !fstat(fileno(fp
), &st
) &&
409 * 12 hour limit is very generous as gc should
410 * never take that long. On the other hand we
411 * don't really need a strict limit here,
412 * running gc --auto one day late is not a big
413 * problem. --force can be used in manual gc
414 * after the user verifies that no gc is
417 time(NULL
) - st
.st_mtime
<= 12 * 3600 &&
418 fscanf(fp
, scan_fmt
, &pid
, locking_host
) == 2 &&
419 /* be gentle to concurrent "gc" on remote hosts */
420 (strcmp(locking_host
, my_host
) || !kill(pid
, 0) || errno
== EPERM
);
425 rollback_lock_file(&lock
);
432 strbuf_addf(&sb
, "%"PRIuMAX
" %s",
433 (uintmax_t) getpid(), my_host
);
434 write_in_full(fd
, sb
.buf
, sb
.len
);
436 commit_lock_file(&lock
);
437 pidfile
= register_tempfile(pidfile_path
);
443 * Returns 0 if there was no previous error and gc can proceed, 1 if
444 * gc should not proceed due to an error in the last run. Prints a
445 * message and returns -1 if an error occured while reading gc.log
447 static int report_last_gc_error(void)
449 struct strbuf sb
= STRBUF_INIT
;
453 char *gc_log_path
= git_pathdup("gc.log");
455 if (stat(gc_log_path
, &st
)) {
459 ret
= error_errno(_("cannot stat '%s'"), gc_log_path
);
463 if (st
.st_mtime
< gc_log_expire_time
)
466 len
= strbuf_read_file(&sb
, gc_log_path
, 0);
468 ret
= error_errno(_("cannot read '%s'"), gc_log_path
);
471 * A previous gc failed. Report the error, and don't
472 * bother with an automatic gc run since it is likely
473 * to fail in the same way.
475 warning(_("The last gc run reported the following. "
476 "Please correct the root cause\n"
478 "Automatic cleanup will not be performed "
479 "until the file is removed.\n\n"
481 gc_log_path
, sb
.buf
);
490 static void gc_before_repack(void)
493 * We may be called twice, as both the pre- and
494 * post-daemonized phases will call us, but running these
495 * commands more than once is pointless and wasteful.
501 if (pack_refs
&& run_command_v_opt(pack_refs_cmd
.argv
, RUN_GIT_CMD
))
502 die(FAILED_RUN
, pack_refs_cmd
.argv
[0]);
504 if (prune_reflogs
&& run_command_v_opt(reflog
.argv
, RUN_GIT_CMD
))
505 die(FAILED_RUN
, reflog
.argv
[0]);
508 int cmd_gc(int argc
, const char **argv
, const char *prefix
)
517 int keep_base_pack
= -1;
520 struct option builtin_gc_options
[] = {
521 OPT__QUIET(&quiet
, N_("suppress progress reporting")),
522 { OPTION_STRING
, 0, "prune", &prune_expire
, N_("date"),
523 N_("prune unreferenced objects"),
524 PARSE_OPT_OPTARG
, NULL
, (intptr_t)prune_expire
},
525 OPT_BOOL(0, "aggressive", &aggressive
, N_("be more thorough (increased runtime)")),
526 OPT_BOOL_F(0, "auto", &auto_gc
, N_("enable auto-gc mode"),
527 PARSE_OPT_NOCOMPLETE
),
528 OPT_BOOL_F(0, "force", &force
,
529 N_("force running gc even if there may be another gc running"),
530 PARSE_OPT_NOCOMPLETE
),
531 OPT_BOOL(0, "keep-largest-pack", &keep_base_pack
,
532 N_("repack all other packs except the largest pack")),
536 if (argc
== 2 && !strcmp(argv
[1], "-h"))
537 usage_with_options(builtin_gc_usage
, builtin_gc_options
);
539 argv_array_pushl(&pack_refs_cmd
, "pack-refs", "--all", "--prune", NULL
);
540 argv_array_pushl(&reflog
, "reflog", "expire", "--all", NULL
);
541 argv_array_pushl(&repack
, "repack", "-d", "-l", NULL
);
542 argv_array_pushl(&prune
, "prune", "--expire", NULL
);
543 argv_array_pushl(&prune_worktrees
, "worktree", "prune", "--expire", NULL
);
544 argv_array_pushl(&rerere
, "rerere", "gc", NULL
);
546 /* default expiry time, overwritten in gc_config */
548 if (parse_expiry_date(gc_log_expire
, &gc_log_expire_time
))
549 die(_("failed to parse gc.logexpiry value %s"), gc_log_expire
);
552 pack_refs
= !is_bare_repository();
554 argc
= parse_options(argc
, argv
, prefix
, builtin_gc_options
,
555 builtin_gc_usage
, 0);
557 usage_with_options(builtin_gc_usage
, builtin_gc_options
);
559 if (prune_expire
&& parse_expiry_date(prune_expire
, &dummy
))
560 die(_("failed to parse prune expiry value %s"), prune_expire
);
563 argv_array_push(&repack
, "-f");
564 if (aggressive_depth
> 0)
565 argv_array_pushf(&repack
, "--depth=%d", aggressive_depth
);
566 if (aggressive_window
> 0)
567 argv_array_pushf(&repack
, "--window=%d", aggressive_window
);
570 argv_array_push(&repack
, "-q");
574 * Auto-gc should be least intrusive as possible.
580 fprintf(stderr
, _("Auto packing the repository in background for optimum performance.\n"));
582 fprintf(stderr
, _("Auto packing the repository for optimum performance.\n"));
583 fprintf(stderr
, _("See \"git help gc\" for manual housekeeping.\n"));
586 int ret
= report_last_gc_error();
588 /* an I/O error occured, already reported */
591 /* Last gc --auto failed. Skip this one. */
594 if (lock_repo_for_gc(force
, &pid
))
596 gc_before_repack(); /* dies on failure */
597 delete_tempfile(&pidfile
);
600 * failure to daemonize is ok, we'll continue
603 daemonized
= !daemonize();
606 struct string_list keep_pack
= STRING_LIST_INIT_NODUP
;
608 if (keep_base_pack
!= -1) {
610 find_base_packs(&keep_pack
, 0);
611 } else if (big_pack_threshold
) {
612 find_base_packs(&keep_pack
, big_pack_threshold
);
615 add_repack_all_option(&keep_pack
);
616 string_list_clear(&keep_pack
, 0);
619 name
= lock_repo_for_gc(force
, &pid
);
622 return 0; /* be quiet on --auto */
623 die(_("gc is already running on machine '%s' pid %"PRIuMAX
" (use --force if not)"),
624 name
, (uintmax_t)pid
);
628 hold_lock_file_for_update(&log_lock
,
631 dup2(get_lock_file_fd(&log_lock
), 2);
632 sigchain_push_common(process_log_file_on_signal
);
633 atexit(process_log_file_at_exit
);
638 if (!repository_format_precious_objects
) {
639 close_all_packs(the_repository
->objects
);
640 if (run_command_v_opt(repack
.argv
, RUN_GIT_CMD
))
641 die(FAILED_RUN
, repack
.argv
[0]);
644 argv_array_push(&prune
, prune_expire
);
646 argv_array_push(&prune
, "--no-progress");
647 if (repository_format_partial_clone
)
648 argv_array_push(&prune
,
649 "--exclude-promisor-objects");
650 if (run_command_v_opt(prune
.argv
, RUN_GIT_CMD
))
651 die(FAILED_RUN
, prune
.argv
[0]);
655 if (prune_worktrees_expire
) {
656 argv_array_push(&prune_worktrees
, prune_worktrees_expire
);
657 if (run_command_v_opt(prune_worktrees
.argv
, RUN_GIT_CMD
))
658 die(FAILED_RUN
, prune_worktrees
.argv
[0]);
661 if (run_command_v_opt(rerere
.argv
, RUN_GIT_CMD
))
662 die(FAILED_RUN
, rerere
.argv
[0]);
664 report_garbage
= report_pack_garbage
;
665 reprepare_packed_git(the_repository
);
666 if (pack_garbage
.nr
> 0) {
667 close_all_packs(the_repository
->objects
);
668 clean_pack_garbage();
671 if (gc_write_commit_graph
)
672 write_commit_graph_reachable(get_object_directory(), 0,
673 !quiet
&& !daemonized
);
675 if (auto_gc
&& too_many_loose_objects())
676 warning(_("There are too many unreachable loose objects; "
677 "run 'git prune' to remove them."));
680 unlink(git_path("gc.log"));