builtin / gc.con commit Merge branch 'en/rename-directory-detection-reboot' (c67de74)
   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
  13#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 "packfile.h"
  24#include "object-store.h"
  25#include "pack.h"
  26#include "pack-objects.h"
  27#include "blob.h"
  28#include "tree.h"
  29
  30#define FAILED_RUN "failed to run %s"
  31
  32static const char * const builtin_gc_usage[] = {
  33        N_("git gc [<options>]"),
  34        NULL
  35};
  36
  37static int pack_refs = 1;
  38static int prune_reflogs = 1;
  39static int aggressive_depth = 50;
  40static int aggressive_window = 250;
  41static int gc_auto_threshold = 6700;
  42static int gc_auto_pack_limit = 50;
  43static int detach_auto = 1;
  44static timestamp_t gc_log_expire_time;
  45static const char *gc_log_expire = "1.day.ago";
  46static const char *prune_expire = "2.weeks.ago";
  47static const char *prune_worktrees_expire = "3.months.ago";
  48static unsigned long big_pack_threshold;
  49static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
  50
  51static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  52static struct argv_array reflog = ARGV_ARRAY_INIT;
  53static struct argv_array repack = ARGV_ARRAY_INIT;
  54static struct argv_array prune = ARGV_ARRAY_INIT;
  55static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  56static struct argv_array rerere = ARGV_ARRAY_INIT;
  57
  58static struct tempfile *pidfile;
  59static struct lock_file log_lock;
  60
  61static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
  62
  63static void clean_pack_garbage(void)
  64{
  65        int i;
  66        for (i = 0; i < pack_garbage.nr; i++)
  67                unlink_or_warn(pack_garbage.items[i].string);
  68        string_list_clear(&pack_garbage, 0);
  69}
  70
  71static void report_pack_garbage(unsigned seen_bits, const char *path)
  72{
  73        if (seen_bits == PACKDIR_FILE_IDX)
  74                string_list_append(&pack_garbage, path);
  75}
  76
  77static void process_log_file(void)
  78{
  79        struct stat st;
  80        if (fstat(get_lock_file_fd(&log_lock), &st)) {
  81                /*
  82                 * Perhaps there was an i/o error or another
  83                 * unlikely situation.  Try to make a note of
  84                 * this in gc.log along with any existing
  85                 * messages.
  86                 */
  87                int saved_errno = errno;
  88                fprintf(stderr, _("Failed to fstat %s: %s"),
  89                        get_tempfile_path(log_lock.tempfile),
  90                        strerror(saved_errno));
  91                fflush(stderr);
  92                commit_lock_file(&log_lock);
  93                errno = saved_errno;
  94        } else if (st.st_size) {
  95                /* There was some error recorded in the lock file */
  96                commit_lock_file(&log_lock);
  97        } else {
  98                /* No error, clean up any old gc.log */
  99                unlink(git_path("gc.log"));
 100                rollback_lock_file(&log_lock);
 101        }
 102}
 103
 104static void process_log_file_at_exit(void)
 105{
 106        fflush(stderr);
 107        process_log_file();
 108}
 109
 110static void process_log_file_on_signal(int signo)
 111{
 112        process_log_file();
 113        sigchain_pop(signo);
 114        raise(signo);
 115}
 116
 117static void gc_config(void)
 118{
 119        const char *value;
 120
 121        if (!git_config_get_value("gc.packrefs", &value)) {
 122                if (value && !strcmp(value, "notbare"))
 123                        pack_refs = -1;
 124                else
 125                        pack_refs = git_config_bool("gc.packrefs", value);
 126        }
 127
 128        git_config_get_int("gc.aggressivewindow", &aggressive_window);
 129        git_config_get_int("gc.aggressivedepth", &aggressive_depth);
 130        git_config_get_int("gc.auto", &gc_auto_threshold);
 131        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
 132        git_config_get_bool("gc.autodetach", &detach_auto);
 133        git_config_get_expiry("gc.pruneexpire", &prune_expire);
 134        git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
 135        git_config_get_expiry("gc.logexpiry", &gc_log_expire);
 136
 137        git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
 138        git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
 139
 140        git_config(git_default_config, NULL);
 141}
 142
 143static int too_many_loose_objects(void)
 144{
 145        /*
 146         * Quickly check if a "gc" is needed, by estimating how
 147         * many loose objects there are.  Because SHA-1 is evenly
 148         * distributed, we can check only one and get a reasonable
 149         * estimate.
 150         */
 151        DIR *dir;
 152        struct dirent *ent;
 153        int auto_threshold;
 154        int num_loose = 0;
 155        int needed = 0;
 156
 157        if (gc_auto_threshold <= 0)
 158                return 0;
 159
 160        dir = opendir(git_path("objects/17"));
 161        if (!dir)
 162                return 0;
 163
 164        auto_threshold = DIV_ROUND_UP(gc_auto_threshold, 256);
 165        while ((ent = readdir(dir)) != NULL) {
 166                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 167                    ent->d_name[38] != '\0')
 168                        continue;
 169                if (++num_loose > auto_threshold) {
 170                        needed = 1;
 171                        break;
 172                }
 173        }
 174        closedir(dir);
 175        return needed;
 176}
 177
 178static struct packed_git *find_base_packs(struct string_list *packs,
 179                                          unsigned long limit)
 180{
 181        struct packed_git *p, *base = NULL;
 182
 183        for (p = get_packed_git(the_repository); p; p = p->next) {
 184                if (!p->pack_local)
 185                        continue;
 186                if (limit) {
 187                        if (p->pack_size >= limit)
 188                                string_list_append(packs, p->pack_name);
 189                } else if (!base || base->pack_size < p->pack_size) {
 190                        base = p;
 191                }
 192        }
 193
 194        if (base)
 195                string_list_append(packs, base->pack_name);
 196
 197        return base;
 198}
 199
 200static int too_many_packs(void)
 201{
 202        struct packed_git *p;
 203        int cnt;
 204
 205        if (gc_auto_pack_limit <= 0)
 206                return 0;
 207
 208        for (cnt = 0, p = get_packed_git(the_repository); p; p = p->next) {
 209                if (!p->pack_local)
 210                        continue;
 211                if (p->pack_keep)
 212                        continue;
 213                /*
 214                 * Perhaps check the size of the pack and count only
 215                 * very small ones here?
 216                 */
 217                cnt++;
 218        }
 219        return gc_auto_pack_limit < cnt;
 220}
 221
 222static uint64_t total_ram(void)
 223{
 224#if defined(HAVE_SYSINFO)
 225        struct sysinfo si;
 226
 227        if (!sysinfo(&si))
 228                return si.totalram;
 229#elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
 230        int64_t physical_memory;
 231        int mib[2];
 232        size_t length;
 233
 234        mib[0] = CTL_HW;
 235# if defined(HW_MEMSIZE)
 236        mib[1] = HW_MEMSIZE;
 237# else
 238        mib[1] = HW_PHYSMEM;
 239# endif
 240        length = sizeof(int64_t);
 241        if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
 242                return physical_memory;
 243#elif defined(GIT_WINDOWS_NATIVE)
 244        MEMORYSTATUSEX memInfo;
 245
 246        memInfo.dwLength = sizeof(MEMORYSTATUSEX);
 247        if (GlobalMemoryStatusEx(&memInfo))
 248                return memInfo.ullTotalPhys;
 249#endif
 250        return 0;
 251}
 252
 253static uint64_t estimate_repack_memory(struct packed_git *pack)
 254{
 255        unsigned long nr_objects = approximate_object_count();
 256        size_t os_cache, heap;
 257
 258        if (!pack || !nr_objects)
 259                return 0;
 260
 261        /*
 262         * First we have to scan through at least one pack.
 263         * Assume enough room in OS file cache to keep the entire pack
 264         * or we may accidentally evict data of other processes from
 265         * the cache.
 266         */
 267        os_cache = pack->pack_size + pack->index_size;
 268        /* then pack-objects needs lots more for book keeping */
 269        heap = sizeof(struct object_entry) * nr_objects;
 270        /*
 271         * internal rev-list --all --objects takes up some memory too,
 272         * let's say half of it is for blobs
 273         */
 274        heap += sizeof(struct blob) * nr_objects / 2;
 275        /*
 276         * and the other half is for trees (commits and tags are
 277         * usually insignificant)
 278         */
 279        heap += sizeof(struct tree) * nr_objects / 2;
 280        /* and then obj_hash[], underestimated in fact */
 281        heap += sizeof(struct object *) * nr_objects;
 282        /* revindex is used also */
 283        heap += sizeof(struct revindex_entry) * nr_objects;
 284        /*
 285         * read_sha1_file() (either at delta calculation phase, or
 286         * writing phase) also fills up the delta base cache
 287         */
 288        heap += delta_base_cache_limit;
 289        /* and of course pack-objects has its own delta cache */
 290        heap += max_delta_cache_size;
 291
 292        return os_cache + heap;
 293}
 294
 295static int keep_one_pack(struct string_list_item *item, void *data)
 296{
 297        argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string));
 298        return 0;
 299}
 300
 301static void add_repack_all_option(struct string_list *keep_pack)
 302{
 303        if (prune_expire && !strcmp(prune_expire, "now"))
 304                argv_array_push(&repack, "-a");
 305        else {
 306                argv_array_push(&repack, "-A");
 307                if (prune_expire)
 308                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 309        }
 310
 311        if (keep_pack)
 312                for_each_string_list(keep_pack, keep_one_pack, NULL);
 313}
 314
 315static void add_repack_incremental_option(void)
 316{
 317       argv_array_push(&repack, "--no-write-bitmap-index");
 318}
 319
 320static int need_to_gc(void)
 321{
 322        /*
 323         * Setting gc.auto to 0 or negative can disable the
 324         * automatic gc.
 325         */
 326        if (gc_auto_threshold <= 0)
 327                return 0;
 328
 329        /*
 330         * If there are too many loose objects, but not too many
 331         * packs, we run "repack -d -l".  If there are too many packs,
 332         * we run "repack -A -d -l".  Otherwise we tell the caller
 333         * there is no need.
 334         */
 335        if (too_many_packs()) {
 336                struct string_list keep_pack = STRING_LIST_INIT_NODUP;
 337
 338                if (big_pack_threshold) {
 339                        find_base_packs(&keep_pack, big_pack_threshold);
 340                        if (keep_pack.nr >= gc_auto_pack_limit) {
 341                                big_pack_threshold = 0;
 342                                string_list_clear(&keep_pack, 0);
 343                                find_base_packs(&keep_pack, 0);
 344                        }
 345                } else {
 346                        struct packed_git *p = find_base_packs(&keep_pack, 0);
 347                        uint64_t mem_have, mem_want;
 348
 349                        mem_have = total_ram();
 350                        mem_want = estimate_repack_memory(p);
 351
 352                        /*
 353                         * Only allow 1/2 of memory for pack-objects, leave
 354                         * the rest for the OS and other processes in the
 355                         * system.
 356                         */
 357                        if (!mem_have || mem_want < mem_have / 2)
 358                                string_list_clear(&keep_pack, 0);
 359                }
 360
 361                add_repack_all_option(&keep_pack);
 362                string_list_clear(&keep_pack, 0);
 363        } else if (too_many_loose_objects())
 364                add_repack_incremental_option();
 365        else
 366                return 0;
 367
 368        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 369                return 0;
 370        return 1;
 371}
 372
 373/* return NULL on success, else hostname running the gc */
 374static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 375{
 376        static struct lock_file lock;
 377        char my_host[HOST_NAME_MAX + 1];
 378        struct strbuf sb = STRBUF_INIT;
 379        struct stat st;
 380        uintmax_t pid;
 381        FILE *fp;
 382        int fd;
 383        char *pidfile_path;
 384
 385        if (is_tempfile_active(pidfile))
 386                /* already locked */
 387                return NULL;
 388
 389        if (xgethostname(my_host, sizeof(my_host)))
 390                xsnprintf(my_host, sizeof(my_host), "unknown");
 391
 392        pidfile_path = git_pathdup("gc.pid");
 393        fd = hold_lock_file_for_update(&lock, pidfile_path,
 394                                       LOCK_DIE_ON_ERROR);
 395        if (!force) {
 396                static char locking_host[HOST_NAME_MAX + 1];
 397                static char *scan_fmt;
 398                int should_exit;
 399
 400                if (!scan_fmt)
 401                        scan_fmt = xstrfmt("%s %%%ds", "%"SCNuMAX, HOST_NAME_MAX);
 402                fp = fopen(pidfile_path, "r");
 403                memset(locking_host, 0, sizeof(locking_host));
 404                should_exit =
 405                        fp != NULL &&
 406                        !fstat(fileno(fp), &st) &&
 407                        /*
 408                         * 12 hour limit is very generous as gc should
 409                         * never take that long. On the other hand we
 410                         * don't really need a strict limit here,
 411                         * running gc --auto one day late is not a big
 412                         * problem. --force can be used in manual gc
 413                         * after the user verifies that no gc is
 414                         * running.
 415                         */
 416                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 417                        fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
 418                        /* be gentle to concurrent "gc" on remote hosts */
 419                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 420                if (fp != NULL)
 421                        fclose(fp);
 422                if (should_exit) {
 423                        if (fd >= 0)
 424                                rollback_lock_file(&lock);
 425                        *ret_pid = pid;
 426                        free(pidfile_path);
 427                        return locking_host;
 428                }
 429        }
 430
 431        strbuf_addf(&sb, "%"PRIuMAX" %s",
 432                    (uintmax_t) getpid(), my_host);
 433        write_in_full(fd, sb.buf, sb.len);
 434        strbuf_release(&sb);
 435        commit_lock_file(&lock);
 436        pidfile = register_tempfile(pidfile_path);
 437        free(pidfile_path);
 438        return NULL;
 439}
 440
 441static int report_last_gc_error(void)
 442{
 443        struct strbuf sb = STRBUF_INIT;
 444        int ret = 0;
 445        struct stat st;
 446        char *gc_log_path = git_pathdup("gc.log");
 447
 448        if (stat(gc_log_path, &st)) {
 449                if (errno == ENOENT)
 450                        goto done;
 451
 452                ret = error_errno(_("Can't stat %s"), gc_log_path);
 453                goto done;
 454        }
 455
 456        if (st.st_mtime < gc_log_expire_time)
 457                goto done;
 458
 459        ret = strbuf_read_file(&sb, gc_log_path, 0);
 460        if (ret > 0)
 461                ret = error(_("The last gc run reported the following. "
 462                               "Please correct the root cause\n"
 463                               "and remove %s.\n"
 464                               "Automatic cleanup will not be performed "
 465                               "until the file is removed.\n\n"
 466                               "%s"),
 467                            gc_log_path, sb.buf);
 468        strbuf_release(&sb);
 469done:
 470        free(gc_log_path);
 471        return ret;
 472}
 473
 474static int gc_before_repack(void)
 475{
 476        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 477                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 478
 479        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 480                return error(FAILED_RUN, reflog.argv[0]);
 481
 482        pack_refs = 0;
 483        prune_reflogs = 0;
 484        return 0;
 485}
 486
 487int cmd_gc(int argc, const char **argv, const char *prefix)
 488{
 489        int aggressive = 0;
 490        int auto_gc = 0;
 491        int quiet = 0;
 492        int force = 0;
 493        const char *name;
 494        pid_t pid;
 495        int daemonized = 0;
 496        int keep_base_pack = -1;
 497        timestamp_t dummy;
 498
 499        struct option builtin_gc_options[] = {
 500                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 501                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 502                        N_("prune unreferenced objects"),
 503                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 504                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 505                OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"),
 506                           PARSE_OPT_NOCOMPLETE),
 507                OPT_BOOL_F(0, "force", &force,
 508                           N_("force running gc even if there may be another gc running"),
 509                           PARSE_OPT_NOCOMPLETE),
 510                OPT_BOOL(0, "keep-largest-pack", &keep_base_pack,
 511                         N_("repack all other packs except the largest pack")),
 512                OPT_END()
 513        };
 514
 515        if (argc == 2 && !strcmp(argv[1], "-h"))
 516                usage_with_options(builtin_gc_usage, builtin_gc_options);
 517
 518        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 519        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 520        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 521        argv_array_pushl(&prune, "prune", "--expire", NULL);
 522        argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 523        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 524
 525        /* default expiry time, overwritten in gc_config */
 526        gc_config();
 527        if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
 528                die(_("failed to parse gc.logexpiry value %s"), gc_log_expire);
 529
 530        if (pack_refs < 0)
 531                pack_refs = !is_bare_repository();
 532
 533        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 534                             builtin_gc_usage, 0);
 535        if (argc > 0)
 536                usage_with_options(builtin_gc_usage, builtin_gc_options);
 537
 538        if (prune_expire && parse_expiry_date(prune_expire, &dummy))
 539                die(_("failed to parse prune expiry value %s"), prune_expire);
 540
 541        if (aggressive) {
 542                argv_array_push(&repack, "-f");
 543                if (aggressive_depth > 0)
 544                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 545                if (aggressive_window > 0)
 546                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 547        }
 548        if (quiet)
 549                argv_array_push(&repack, "-q");
 550
 551        if (auto_gc) {
 552                /*
 553                 * Auto-gc should be least intrusive as possible.
 554                 */
 555                if (!need_to_gc())
 556                        return 0;
 557                if (!quiet) {
 558                        if (detach_auto)
 559                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 560                        else
 561                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 562                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 563                }
 564                if (detach_auto) {
 565                        if (report_last_gc_error())
 566                                return -1;
 567
 568                        if (lock_repo_for_gc(force, &pid))
 569                                return 0;
 570                        if (gc_before_repack())
 571                                return -1;
 572                        delete_tempfile(&pidfile);
 573
 574                        /*
 575                         * failure to daemonize is ok, we'll continue
 576                         * in foreground
 577                         */
 578                        daemonized = !daemonize();
 579                }
 580        } else {
 581                struct string_list keep_pack = STRING_LIST_INIT_NODUP;
 582
 583                if (keep_base_pack != -1) {
 584                        if (keep_base_pack)
 585                                find_base_packs(&keep_pack, 0);
 586                } else if (big_pack_threshold) {
 587                        find_base_packs(&keep_pack, big_pack_threshold);
 588                }
 589
 590                add_repack_all_option(&keep_pack);
 591                string_list_clear(&keep_pack, 0);
 592        }
 593
 594        name = lock_repo_for_gc(force, &pid);
 595        if (name) {
 596                if (auto_gc)
 597                        return 0; /* be quiet on --auto */
 598                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 599                    name, (uintmax_t)pid);
 600        }
 601
 602        if (daemonized) {
 603                hold_lock_file_for_update(&log_lock,
 604                                          git_path("gc.log"),
 605                                          LOCK_DIE_ON_ERROR);
 606                dup2(get_lock_file_fd(&log_lock), 2);
 607                sigchain_push_common(process_log_file_on_signal);
 608                atexit(process_log_file_at_exit);
 609        }
 610
 611        if (gc_before_repack())
 612                return -1;
 613
 614        if (!repository_format_precious_objects) {
 615                if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 616                        return error(FAILED_RUN, repack.argv[0]);
 617
 618                if (prune_expire) {
 619                        argv_array_push(&prune, prune_expire);
 620                        if (quiet)
 621                                argv_array_push(&prune, "--no-progress");
 622                        if (repository_format_partial_clone)
 623                                argv_array_push(&prune,
 624                                                "--exclude-promisor-objects");
 625                        if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 626                                return error(FAILED_RUN, prune.argv[0]);
 627                }
 628        }
 629
 630        if (prune_worktrees_expire) {
 631                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 632                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 633                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 634        }
 635
 636        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 637                return error(FAILED_RUN, rerere.argv[0]);
 638
 639        report_garbage = report_pack_garbage;
 640        reprepare_packed_git(the_repository);
 641        if (pack_garbage.nr > 0)
 642                clean_pack_garbage();
 643
 644        if (auto_gc && too_many_loose_objects())
 645                warning(_("There are too many unreachable loose objects; "
 646                        "run 'git prune' to remove them."));
 647
 648        if (!daemonized)
 649                unlink(git_path("gc.log"));
 650
 651        return 0;
 652}