diff options
Diffstat (limited to 'builtin/gc.c')
| -rw-r--r-- | builtin/gc.c | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/builtin/gc.c b/builtin/gc.c new file mode 100644 index 0000000000..a22b6ff683 --- /dev/null +++ b/builtin/gc.c @@ -0,0 +1,700 @@ +/* + * 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" + +#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 (repository_format_partial_clone) + 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; +} |