/* * git gc builtin command * * Cleanup unreachable files and optimize the repository. * * Copyright (c) 2007 James Bowes * * Based on git-gc.sh, which is * * Copyright (c) 2006 Shawn O. Pearce */ #include "builtin.h" #include "repository.h" #include "config.h" #include "tempfile.h" #include "lockfile.h" #include "parse-options.h" #include "run-command.h" #include "sigchain.h" #include "argv-array.h" #include "commit.h" #include "commit-graph.h" #include "packfile.h" #include "object-store.h" #include "pack.h" #include "pack-objects.h" #include "blob.h" #include "tree.h" #include "promisor-remote.h" #define FAILED_RUN "failed to run %s" static const char * const builtin_gc_usage[] = { N_("git gc [<options>]"), NULL }; static int pack_refs = 1; static int prune_reflogs = 1; static int aggressive_depth = 50; static int aggressive_window = 250; static int gc_auto_threshold = 6700; static int gc_auto_pack_limit = 50; static int detach_auto = 1; static timestamp_t gc_log_expire_time; static const char *gc_log_expire = "1.day.ago"; static const char *prune_expire = "2.weeks.ago"; static const char *prune_worktrees_expire = "3.months.ago"; static unsigned long big_pack_threshold; static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE; static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT; static struct argv_array reflog = ARGV_ARRAY_INIT; static struct argv_array repack = ARGV_ARRAY_INIT; static struct argv_array prune = ARGV_ARRAY_INIT; static struct argv_array prune_worktrees = ARGV_ARRAY_INIT; static struct argv_array rerere = ARGV_ARRAY_INIT; static struct tempfile *pidfile; static struct lock_file log_lock; static struct string_list pack_garbage = STRING_LIST_INIT_DUP; static void clean_pack_garbage(void) { int i; for (i = 0; i < pack_garbage.nr; i++) unlink_or_warn(pack_garbage.items[i].string); string_list_clear(&pack_garbage, 0); } static void report_pack_garbage(unsigned seen_bits, const char *path) { if (seen_bits == PACKDIR_FILE_IDX) string_list_append(&pack_garbage, path); } static void process_log_file(void) { struct stat st; if (fstat(get_lock_file_fd(&log_lock), &st)) { /* * Perhaps there was an i/o error or another * unlikely situation. Try to make a note of * this in gc.log along with any existing * messages. */ int saved_errno = errno; fprintf(stderr, _("Failed to fstat %s: %s"), get_tempfile_path(log_lock.tempfile), strerror(saved_errno)); fflush(stderr); commit_lock_file(&log_lock); errno = saved_errno; } else if (st.st_size) { /* There was some error recorded in the lock file */ commit_lock_file(&log_lock); } else { /* No error, clean up any old gc.log */ unlink(git_path("gc.log")); rollback_lock_file(&log_lock); } } static void process_log_file_at_exit(void) { fflush(stderr); process_log_file(); } static void process_log_file_on_signal(int signo) { process_log_file(); sigchain_pop(signo); raise(signo); } static int gc_config_is_timestamp_never(const char *var) { const char *value; timestamp_t expire; if (!git_config_get_value(var, &value) && value) { if (parse_expiry_date(value, &expire)) die(_("failed to parse '%s' value '%s'"), var, value); return expire == 0; } return 0; } static void gc_config(void) { const char *value; if (!git_config_get_value("gc.packrefs", &value)) { if (value && !strcmp(value, "notbare")) pack_refs = -1; else pack_refs = git_config_bool("gc.packrefs", value); } if (gc_config_is_timestamp_never("gc.reflogexpire") && gc_config_is_timestamp_never("gc.reflogexpireunreachable")) prune_reflogs = 0; git_config_get_int("gc.aggressivewindow", &aggressive_window); git_config_get_int("gc.aggressivedepth", &aggressive_depth); git_config_get_int("gc.auto", &gc_auto_threshold); git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit); git_config_get_bool("gc.autodetach", &detach_auto); git_config_get_expiry("gc.pruneexpire", &prune_expire); git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire); git_config_get_expiry("gc.logexpiry", &gc_log_expire); git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold); git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size); git_config(git_default_config, NULL); } static int too_many_loose_objects(void) { /* * Quickly check if a "gc" is needed, by estimating how * many loose objects there are. Because SHA-1 is evenly * distributed, we can check only one and get a reasonable * estimate. */ DIR *dir; struct dirent *ent; int auto_threshold; int num_loose = 0; int needed = 0; const unsigned hexsz_loose = the_hash_algo->hexsz - 2; dir = opendir(git_path("objects/17")); if (!dir) return 0; auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256); while ((ent = readdir(dir)) != NULL) { if (strspn(ent->d_name, "0123456789abcdef") != hexsz_loose || ent->d_name[hexsz_loose] != '\0') continue; if (++num_loose > auto_threshold) { needed = 1; break; } } closedir(dir); return needed; } static struct packed_git *find_base_packs(struct string_list *packs, unsigned long limit) { struct packed_git *p, *base = NULL; for (p = get_all_packs(the_repository); p; p = p->next) { if (!p->pack_local) continue; if (limit) { if (p->pack_size >= limit) string_list_append(packs, p->pack_name); } else if (!base || base->pack_size < p->pack_size) { base = p; } } if (base) string_list_append(packs, base->pack_name); return base; } static int too_many_packs(void) { struct packed_git *p; int cnt; if (gc_auto_pack_limit <= 0) return 0; for (cnt = 0, p = get_all_packs(the_repository); p; p = p->next) { if (!p->pack_local) continue; if (p->pack_keep) continue; /* * Perhaps check the size of the pack and count only * very small ones here? */ cnt++; } return gc_auto_pack_limit < cnt; } static uint64_t total_ram(void) { #if defined(HAVE_SYSINFO) struct sysinfo si; if (!sysinfo(&si)) return si.totalram; #elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM)) int64_t physical_memory; int mib[2]; size_t length; mib[0] = CTL_HW; # if defined(HW_MEMSIZE) mib[1] = HW_MEMSIZE; # else mib[1] = HW_PHYSMEM; # endif length = sizeof(int64_t); if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0)) return physical_memory; #elif defined(GIT_WINDOWS_NATIVE) MEMORYSTATUSEX memInfo; memInfo.dwLength = sizeof(MEMORYSTATUSEX); if (GlobalMemoryStatusEx(&memInfo)) return memInfo.ullTotalPhys; #endif return 0; } static uint64_t estimate_repack_memory(struct packed_git *pack) { unsigned long nr_objects = approximate_object_count(); size_t os_cache, heap; if (!pack || !nr_objects) return 0; /* * First we have to scan through at least one pack. * Assume enough room in OS file cache to keep the entire pack * or we may accidentally evict data of other processes from * the cache. */ os_cache = pack->pack_size + pack->index_size; /* then pack-objects needs lots more for book keeping */ heap = sizeof(struct object_entry) * nr_objects; /* * internal rev-list --all --objects takes up some memory too, * let's say half of it is for blobs */ heap += sizeof(struct blob) * nr_objects / 2; /* * and the other half is for trees (commits and tags are * usually insignificant) */ heap += sizeof(struct tree) * nr_objects / 2; /* and then obj_hash[], underestimated in fact */ heap += sizeof(struct object *) * nr_objects; /* revindex is used also */ heap += sizeof(struct revindex_entry) * nr_objects; /* * read_sha1_file() (either at delta calculation phase, or * writing phase) also fills up the delta base cache */ heap += delta_base_cache_limit; /* and of course pack-objects has its own delta cache */ heap += max_delta_cache_size; return os_cache + heap; } static int keep_one_pack(struct string_list_item *item, void *data) { argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string)); return 0; } static void add_repack_all_option(struct string_list *keep_pack) { if (prune_expire && !strcmp(prune_expire, "now")) argv_array_push(&repack, "-a"); else { argv_array_push(&repack, "-A"); if (prune_expire) argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire); } if (keep_pack) for_each_string_list(keep_pack, keep_one_pack, NULL); } static void add_repack_incremental_option(void) { argv_array_push(&repack, "--no-write-bitmap-index"); } static int need_to_gc(void) { /* * Setting gc.auto to 0 or negative can disable the * automatic gc. */ if (gc_auto_threshold <= 0) return 0; /* * If there are too many loose objects, but not too many * packs, we run "repack -d -l". If there are too many packs, * we run "repack -A -d -l". Otherwise we tell the caller * there is no need. */ if (too_many_packs()) { struct string_list keep_pack = STRING_LIST_INIT_NODUP; if (big_pack_threshold) { find_base_packs(&keep_pack, big_pack_threshold); if (keep_pack.nr >= gc_auto_pack_limit) { big_pack_threshold = 0; string_list_clear(&keep_pack, 0); find_base_packs(&keep_pack, 0); } } else { struct packed_git *p = find_base_packs(&keep_pack, 0); uint64_t mem_have, mem_want; mem_have = total_ram(); mem_want = estimate_repack_memory(p); /* * Only allow 1/2 of memory for pack-objects, leave * the rest for the OS and other processes in the * system. */ if (!mem_have || mem_want < mem_have / 2) string_list_clear(&keep_pack, 0); } add_repack_all_option(&keep_pack); string_list_clear(&keep_pack, 0); } else if (too_many_loose_objects()) add_repack_incremental_option(); else return 0; if (run_hook_le(NULL, "pre-auto-gc", NULL)) return 0; return 1; } /* return NULL on success, else hostname running the gc */ static const char *lock_repo_for_gc(int force, pid_t* ret_pid) { struct lock_file lock = LOCK_INIT; char my_host[HOST_NAME_MAX + 1]; struct strbuf sb = STRBUF_INIT; struct stat st; uintmax_t pid; FILE *fp; int fd; char *pidfile_path; if (is_tempfile_active(pidfile)) /* already locked */ return NULL; if (xgethostname(my_host, sizeof(my_host))) xsnprintf(my_host, sizeof(my_host), "unknown"); pidfile_path = git_pathdup("gc.pid"); fd = hold_lock_file_for_update(&lock, pidfile_path, LOCK_DIE_ON_ERROR); if (!force) { static char locking_host[HOST_NAME_MAX + 1]; static char *scan_fmt; int should_exit; if (!scan_fmt) scan_fmt = xstrfmt("%s %%%ds", "%"SCNuMAX, HOST_NAME_MAX); fp = fopen(pidfile_path, "r"); memset(locking_host, 0, sizeof(locking_host)); should_exit = fp != NULL && !fstat(fileno(fp), &st) && /* * 12 hour limit is very generous as gc should * never take that long. On the other hand we * don't really need a strict limit here, * running gc --auto one day late is not a big * problem. --force can be used in manual gc * after the user verifies that no gc is * running. */ time(NULL) - st.st_mtime <= 12 * 3600 && fscanf(fp, scan_fmt, &pid, locking_host) == 2 && /* be gentle to concurrent "gc" on remote hosts */ (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM); if (fp != NULL) fclose(fp); if (should_exit) { if (fd >= 0) rollback_lock_file(&lock); *ret_pid = pid; free(pidfile_path); return locking_host; } } strbuf_addf(&sb, "%"PRIuMAX" %s", (uintmax_t) getpid(), my_host); write_in_full(fd, sb.buf, sb.len); strbuf_release(&sb); commit_lock_file(&lock); pidfile = register_tempfile(pidfile_path); free(pidfile_path); return NULL; } /* * Returns 0 if there was no previous error and gc can proceed, 1 if * gc should not proceed due to an error in the last run. Prints a * message and returns -1 if an error occured while reading gc.log */ static int report_last_gc_error(void) { struct strbuf sb = STRBUF_INIT; int ret = 0; ssize_t len; struct stat st; char *gc_log_path = git_pathdup("gc.log"); if (stat(gc_log_path, &st)) { if (errno == ENOENT) goto done; ret = error_errno(_("cannot stat '%s'"), gc_log_path); goto done; } if (st.st_mtime < gc_log_expire_time) goto done; len = strbuf_read_file(&sb, gc_log_path, 0); if (len < 0) ret = error_errno(_("cannot read '%s'"), gc_log_path); else if (len > 0) { /* * A previous gc failed. Report the error, and don't * bother with an automatic gc run since it is likely * to fail in the same way. */ warning(_("The last gc run reported the following. " "Please correct the root cause\n" "and remove %s.\n" "Automatic cleanup will not be performed " "until the file is removed.\n\n" "%s"), gc_log_path, sb.buf); ret = 1; } strbuf_release(&sb); done: free(gc_log_path); return ret; } static void gc_before_repack(void) { /* * We may be called twice, as both the pre- and * post-daemonized phases will call us, but running these * commands more than once is pointless and wasteful. */ static int done = 0; if (done++) return; if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD)) die(FAILED_RUN, pack_refs_cmd.argv[0]); if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD)) die(FAILED_RUN, reflog.argv[0]); } int cmd_gc(int argc, const char **argv, const char *prefix) { int aggressive = 0; int auto_gc = 0; int quiet = 0; int force = 0; const char *name; pid_t pid; int daemonized = 0; int keep_base_pack = -1; timestamp_t dummy; struct option builtin_gc_options[] = { OPT__QUIET(&quiet, N_("suppress progress reporting")), { OPTION_STRING, 0, "prune", &prune_expire, N_("date"), N_("prune unreferenced objects"), PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire }, OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")), OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"), PARSE_OPT_NOCOMPLETE), OPT_BOOL_F(0, "force", &force, N_("force running gc even if there may be another gc running"), PARSE_OPT_NOCOMPLETE), OPT_BOOL(0, "keep-largest-pack", &keep_base_pack, N_("repack all other packs except the largest pack")), OPT_END() }; if (argc == 2 && !strcmp(argv[1], "-h")) usage_with_options(builtin_gc_usage, builtin_gc_options); argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL); argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL); argv_array_pushl(&repack, "repack", "-d", "-l", NULL); argv_array_pushl(&prune, "prune", "--expire", NULL); argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL); argv_array_pushl(&rerere, "rerere", "gc", NULL); /* default expiry time, overwritten in gc_config */ gc_config(); if (parse_expiry_date(gc_log_expire, &gc_log_expire_time)) die(_("failed to parse gc.logexpiry value %s"), gc_log_expire); if (pack_refs < 0) pack_refs = !is_bare_repository(); argc = parse_options(argc, argv, prefix, builtin_gc_options, builtin_gc_usage, 0); if (argc > 0) usage_with_options(builtin_gc_usage, builtin_gc_options); if (prune_expire && parse_expiry_date(prune_expire, &dummy)) die(_("failed to parse prune expiry value %s"), prune_expire); if (aggressive) { argv_array_push(&repack, "-f"); if (aggressive_depth > 0) argv_array_pushf(&repack, "--depth=%d", aggressive_depth); if (aggressive_window > 0) argv_array_pushf(&repack, "--window=%d", aggressive_window); } if (quiet) argv_array_push(&repack, "-q"); if (auto_gc) { /* * Auto-gc should be least intrusive as possible. */ if (!need_to_gc()) return 0; if (!quiet) { if (detach_auto) fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n")); else fprintf(stderr, _("Auto packing the repository for optimum performance.\n")); fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n")); } if (detach_auto) { int ret = report_last_gc_error(); if (ret < 0) /* an I/O error occured, already reported */ exit(128); if (ret == 1) /* Last gc --auto failed. Skip this one. */ return 0; if (lock_repo_for_gc(force, &pid)) return 0; gc_before_repack(); /* dies on failure */ delete_tempfile(&pidfile); /* * failure to daemonize is ok, we'll continue * in foreground */ daemonized = !daemonize(); } } else { struct string_list keep_pack = STRING_LIST_INIT_NODUP; if (keep_base_pack != -1) { if (keep_base_pack) find_base_packs(&keep_pack, 0); } else if (big_pack_threshold) { find_base_packs(&keep_pack, big_pack_threshold); } add_repack_all_option(&keep_pack); string_list_clear(&keep_pack, 0); } name = lock_repo_for_gc(force, &pid); if (name) { if (auto_gc) return 0; /* be quiet on --auto */ die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"), name, (uintmax_t)pid); } if (daemonized) { hold_lock_file_for_update(&log_lock, git_path("gc.log"), LOCK_DIE_ON_ERROR); dup2(get_lock_file_fd(&log_lock), 2); sigchain_push_common(process_log_file_on_signal); atexit(process_log_file_at_exit); } gc_before_repack(); if (!repository_format_precious_objects) { close_object_store(the_repository->objects); if (run_command_v_opt(repack.argv, RUN_GIT_CMD)) die(FAILED_RUN, repack.argv[0]); if (prune_expire) { argv_array_push(&prune, prune_expire); if (quiet) argv_array_push(&prune, "--no-progress"); if (has_promisor_remote()) argv_array_push(&prune, "--exclude-promisor-objects"); if (run_command_v_opt(prune.argv, RUN_GIT_CMD)) die(FAILED_RUN, prune.argv[0]); } } if (prune_worktrees_expire) { argv_array_push(&prune_worktrees, prune_worktrees_expire); if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD)) die(FAILED_RUN, prune_worktrees.argv[0]); } if (run_command_v_opt(rerere.argv, RUN_GIT_CMD)) die(FAILED_RUN, rerere.argv[0]); report_garbage = report_pack_garbage; reprepare_packed_git(the_repository); if (pack_garbage.nr > 0) { close_object_store(the_repository->objects); clean_pack_garbage(); } prepare_repo_settings(the_repository); if (the_repository->settings.gc_write_commit_graph == 1) write_commit_graph_reachable(get_object_directory(), !quiet && !daemonized ? COMMIT_GRAPH_WRITE_PROGRESS : 0, NULL); if (auto_gc && too_many_loose_objects()) warning(_("There are too many unreachable loose objects; " "run 'git prune' to remove them.")); if (!daemonized) unlink(git_path("gc.log")); return 0; }