Andrew's git / gitweb.git / builtin/gc.c
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builtin / gc.con commit ls-remote: release memory instead of UNLEAK (deec6b8)
   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 "commit-graph.h"
  24#include "packfile.h"
  25#include "object-store.h"
  26#include "pack.h"
  27#include "pack-objects.h"
  28#include "blob.h"
  29#include "tree.h"
  30
  31#define FAILED_RUN "failed to run %s"
  32
  33static const char * const builtin_gc_usage[] = {
  34        N_("git gc [<options>]"),
  35        NULL
  36};
  37
  38static int pack_refs = 1;
  39static int prune_reflogs = 1;
  40static int aggressive_depth = 50;
  41static int aggressive_window = 250;
  42static int gc_auto_threshold = 6700;
  43static int gc_auto_pack_limit = 50;
  44static int gc_write_commit_graph;
  45static int detach_auto = 1;
  46static timestamp_t gc_log_expire_time;
  47static const char *gc_log_expire = "1.day.ago";
  48static const char *prune_expire = "2.weeks.ago";
  49static const char *prune_worktrees_expire = "3.months.ago";
  50static unsigned long big_pack_threshold;
  51static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
  52
  53static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  54static struct argv_array reflog = ARGV_ARRAY_INIT;
  55static struct argv_array repack = ARGV_ARRAY_INIT;
  56static struct argv_array prune = ARGV_ARRAY_INIT;
  57static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  58static struct argv_array rerere = ARGV_ARRAY_INIT;
  59
  60static struct tempfile *pidfile;
  61static struct lock_file log_lock;
  62
  63static struct string_list pack_garbage = STRING_LIST_INIT_DUP;
  64
  65static void clean_pack_garbage(void)
  66{
  67        int i;
  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);
  71}
  72
  73static void report_pack_garbage(unsigned seen_bits, const char *path)
  74{
  75        if (seen_bits == PACKDIR_FILE_IDX)
  76                string_list_append(&pack_garbage, path);
  77}
  78
  79static void process_log_file(void)
  80{
  81        struct stat st;
  82        if (fstat(get_lock_file_fd(&log_lock), &st)) {
  83                /*
  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
  87                 * messages.
  88                 */
  89                int saved_errno = errno;
  90                fprintf(stderr, _("Failed to fstat %s: %s"),
  91                        get_tempfile_path(log_lock.tempfile),
  92                        strerror(saved_errno));
  93                fflush(stderr);
  94                commit_lock_file(&log_lock);
  95                errno = saved_errno;
  96        } else if (st.st_size) {
  97                /* There was some error recorded in the lock file */
  98                commit_lock_file(&log_lock);
  99        } else {
 100                /* No error, clean up any old gc.log */
 101                unlink(git_path("gc.log"));
 102                rollback_lock_file(&log_lock);
 103        }
 104}
 105
 106static void process_log_file_at_exit(void)
 107{
 108        fflush(stderr);
 109        process_log_file();
 110}
 111
 112static void process_log_file_on_signal(int signo)
 113{
 114        process_log_file();
 115        sigchain_pop(signo);
 116        raise(signo);
 117}
 118
 119static void gc_config(void)
 120{
 121        const char *value;
 122
 123        if (!git_config_get_value("gc.packrefs", &value)) {
 124                if (value && !strcmp(value, "notbare"))
 125                        pack_refs = -1;
 126                else
 127                        pack_refs = git_config_bool("gc.packrefs", value);
 128        }
 129
 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);
 139
 140        git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
 141        git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
 142
 143        git_config(git_default_config, NULL);
 144}
 145
 146static int too_many_loose_objects(void)
 147{
 148        /*
 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
 152         * estimate.
 153         */
 154        DIR *dir;
 155        struct dirent *ent;
 156        int auto_threshold;
 157        int num_loose = 0;
 158        int needed = 0;
 159
 160        if (gc_auto_threshold <= 0)
 161                return 0;
 162
 163        dir = opendir(git_path("objects/17"));
 164        if (!dir)
 165                return 0;
 166
 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')
 171                        continue;
 172                if (++num_loose > auto_threshold) {
 173                        needed = 1;
 174                        break;
 175                }
 176        }
 177        closedir(dir);
 178        return needed;
 179}
 180
 181static struct packed_git *find_base_packs(struct string_list *packs,
 182                                          unsigned long limit)
 183{
 184        struct packed_git *p, *base = NULL;
 185
 186        for (p = get_all_packs(the_repository); p; p = p->next) {
 187                if (!p->pack_local)
 188                        continue;
 189                if (limit) {
 190                        if (p->pack_size >= limit)
 191                                string_list_append(packs, p->pack_name);
 192                } else if (!base || base->pack_size < p->pack_size) {
 193                        base = p;
 194                }
 195        }
 196
 197        if (base)
 198                string_list_append(packs, base->pack_name);
 199
 200        return base;
 201}
 202
 203static int too_many_packs(void)
 204{
 205        struct packed_git *p;
 206        int cnt;
 207
 208        if (gc_auto_pack_limit <= 0)
 209                return 0;
 210
 211        for (cnt = 0, p = get_all_packs(the_repository); p; p = p->next) {
 212                if (!p->pack_local)
 213                        continue;
 214                if (p->pack_keep)
 215                        continue;
 216                /*
 217                 * Perhaps check the size of the pack and count only
 218                 * very small ones here?
 219                 */
 220                cnt++;
 221        }
 222        return gc_auto_pack_limit < cnt;
 223}
 224
 225static uint64_t total_ram(void)
 226{
 227#if defined(HAVE_SYSINFO)
 228        struct sysinfo si;
 229
 230        if (!sysinfo(&si))
 231                return si.totalram;
 232#elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
 233        int64_t physical_memory;
 234        int mib[2];
 235        size_t length;
 236
 237        mib[0] = CTL_HW;
 238# if defined(HW_MEMSIZE)
 239        mib[1] = HW_MEMSIZE;
 240# else
 241        mib[1] = HW_PHYSMEM;
 242# endif
 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;
 248
 249        memInfo.dwLength = sizeof(MEMORYSTATUSEX);
 250        if (GlobalMemoryStatusEx(&memInfo))
 251                return memInfo.ullTotalPhys;
 252#endif
 253        return 0;
 254}
 255
 256static uint64_t estimate_repack_memory(struct packed_git *pack)
 257{
 258        unsigned long nr_objects = approximate_object_count();
 259        size_t os_cache, heap;
 260
 261        if (!pack || !nr_objects)
 262                return 0;
 263
 264        /*
 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
 268         * the cache.
 269         */
 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;
 273        /*
 274         * internal rev-list --all --objects takes up some memory too,
 275         * let's say half of it is for blobs
 276         */
 277        heap += sizeof(struct blob) * nr_objects / 2;
 278        /*
 279         * and the other half is for trees (commits and tags are
 280         * usually insignificant)
 281         */
 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;
 287        /*
 288         * read_sha1_file() (either at delta calculation phase, or
 289         * writing phase) also fills up the delta base cache
 290         */
 291        heap += delta_base_cache_limit;
 292        /* and of course pack-objects has its own delta cache */
 293        heap += max_delta_cache_size;
 294
 295        return os_cache + heap;
 296}
 297
 298static int keep_one_pack(struct string_list_item *item, void *data)
 299{
 300        argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string));
 301        return 0;
 302}
 303
 304static void add_repack_all_option(struct string_list *keep_pack)
 305{
 306        if (prune_expire && !strcmp(prune_expire, "now"))
 307                argv_array_push(&repack, "-a");
 308        else {
 309                argv_array_push(&repack, "-A");
 310                if (prune_expire)
 311                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 312        }
 313
 314        if (keep_pack)
 315                for_each_string_list(keep_pack, keep_one_pack, NULL);
 316}
 317
 318static void add_repack_incremental_option(void)
 319{
 320       argv_array_push(&repack, "--no-write-bitmap-index");
 321}
 322
 323static int need_to_gc(void)
 324{
 325        /*
 326         * Setting gc.auto to 0 or negative can disable the
 327         * automatic gc.
 328         */
 329        if (gc_auto_threshold <= 0)
 330                return 0;
 331
 332        /*
 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
 336         * there is no need.
 337         */
 338        if (too_many_packs()) {
 339                struct string_list keep_pack = STRING_LIST_INIT_NODUP;
 340
 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);
 347                        }
 348                } else {
 349                        struct packed_git *p = find_base_packs(&keep_pack, 0);
 350                        uint64_t mem_have, mem_want;
 351
 352                        mem_have = total_ram();
 353                        mem_want = estimate_repack_memory(p);
 354
 355                        /*
 356                         * Only allow 1/2 of memory for pack-objects, leave
 357                         * the rest for the OS and other processes in the
 358                         * system.
 359                         */
 360                        if (!mem_have || mem_want < mem_have / 2)
 361                                string_list_clear(&keep_pack, 0);
 362                }
 363
 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();
 368        else
 369                return 0;
 370
 371        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 372                return 0;
 373        return 1;
 374}
 375
 376/* return NULL on success, else hostname running the gc */
 377static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 378{
 379        struct lock_file lock = LOCK_INIT;
 380        char my_host[HOST_NAME_MAX + 1];
 381        struct strbuf sb = STRBUF_INIT;
 382        struct stat st;
 383        uintmax_t pid;
 384        FILE *fp;
 385        int fd;
 386        char *pidfile_path;
 387
 388        if (is_tempfile_active(pidfile))
 389                /* already locked */
 390                return NULL;
 391
 392        if (xgethostname(my_host, sizeof(my_host)))
 393                xsnprintf(my_host, sizeof(my_host), "unknown");
 394
 395        pidfile_path = git_pathdup("gc.pid");
 396        fd = hold_lock_file_for_update(&lock, pidfile_path,
 397                                       LOCK_DIE_ON_ERROR);
 398        if (!force) {
 399                static char locking_host[HOST_NAME_MAX + 1];
 400                static char *scan_fmt;
 401                int should_exit;
 402
 403                if (!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));
 407                should_exit =
 408                        fp != NULL &&
 409                        !fstat(fileno(fp), &st) &&
 410                        /*
 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
 417                         * running.
 418                         */
 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);
 423                if (fp != NULL)
 424                        fclose(fp);
 425                if (should_exit) {
 426                        if (fd >= 0)
 427                                rollback_lock_file(&lock);
 428                        *ret_pid = pid;
 429                        free(pidfile_path);
 430                        return locking_host;
 431                }
 432        }
 433
 434        strbuf_addf(&sb, "%"PRIuMAX" %s",
 435                    (uintmax_t) getpid(), my_host);
 436        write_in_full(fd, sb.buf, sb.len);
 437        strbuf_release(&sb);
 438        commit_lock_file(&lock);
 439        pidfile = register_tempfile(pidfile_path);
 440        free(pidfile_path);
 441        return NULL;
 442}
 443
 444static int report_last_gc_error(void)
 445{
 446        struct strbuf sb = STRBUF_INIT;
 447        int ret = 0;
 448        struct stat st;
 449        char *gc_log_path = git_pathdup("gc.log");
 450
 451        if (stat(gc_log_path, &st)) {
 452                if (errno == ENOENT)
 453                        goto done;
 454
 455                ret = error_errno(_("Can't stat %s"), gc_log_path);
 456                goto done;
 457        }
 458
 459        if (st.st_mtime < gc_log_expire_time)
 460                goto done;
 461
 462        ret = strbuf_read_file(&sb, gc_log_path, 0);
 463        if (ret > 0)
 464                ret = error(_("The last gc run reported the following. "
 465                               "Please correct the root cause\n"
 466                               "and remove %s.\n"
 467                               "Automatic cleanup will not be performed "
 468                               "until the file is removed.\n\n"
 469                               "%s"),
 470                            gc_log_path, sb.buf);
 471        strbuf_release(&sb);
 472done:
 473        free(gc_log_path);
 474        return ret;
 475}
 476
 477static int gc_before_repack(void)
 478{
 479        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 480                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 481
 482        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 483                return error(FAILED_RUN, reflog.argv[0]);
 484
 485        pack_refs = 0;
 486        prune_reflogs = 0;
 487        return 0;
 488}
 489
 490int cmd_gc(int argc, const char **argv, const char *prefix)
 491{
 492        int aggressive = 0;
 493        int auto_gc = 0;
 494        int quiet = 0;
 495        int force = 0;
 496        const char *name;
 497        pid_t pid;
 498        int daemonized = 0;
 499        int keep_base_pack = -1;
 500        timestamp_t dummy;
 501
 502        struct option builtin_gc_options[] = {
 503                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 504                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 505                        N_("prune unreferenced objects"),
 506                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 507                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 508                OPT_BOOL_F(0, "auto", &auto_gc, N_("enable auto-gc mode"),
 509                           PARSE_OPT_NOCOMPLETE),
 510                OPT_BOOL_F(0, "force", &force,
 511                           N_("force running gc even if there may be another gc running"),
 512                           PARSE_OPT_NOCOMPLETE),
 513                OPT_BOOL(0, "keep-largest-pack", &keep_base_pack,
 514                         N_("repack all other packs except the largest pack")),
 515                OPT_END()
 516        };
 517
 518        if (argc == 2 && !strcmp(argv[1], "-h"))
 519                usage_with_options(builtin_gc_usage, builtin_gc_options);
 520
 521        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 522        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 523        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 524        argv_array_pushl(&prune, "prune", "--expire", NULL);
 525        argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 526        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 527
 528        /* default expiry time, overwritten in gc_config */
 529        gc_config();
 530        if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
 531                die(_("failed to parse gc.logexpiry value %s"), gc_log_expire);
 532
 533        if (pack_refs < 0)
 534                pack_refs = !is_bare_repository();
 535
 536        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 537                             builtin_gc_usage, 0);
 538        if (argc > 0)
 539                usage_with_options(builtin_gc_usage, builtin_gc_options);
 540
 541        if (prune_expire && parse_expiry_date(prune_expire, &dummy))
 542                die(_("failed to parse prune expiry value %s"), prune_expire);
 543
 544        if (aggressive) {
 545                argv_array_push(&repack, "-f");
 546                if (aggressive_depth > 0)
 547                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 548                if (aggressive_window > 0)
 549                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 550        }
 551        if (quiet)
 552                argv_array_push(&repack, "-q");
 553
 554        if (auto_gc) {
 555                /*
 556                 * Auto-gc should be least intrusive as possible.
 557                 */
 558                if (!need_to_gc())
 559                        return 0;
 560                if (!quiet) {
 561                        if (detach_auto)
 562                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 563                        else
 564                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 565                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 566                }
 567                if (detach_auto) {
 568                        if (report_last_gc_error())
 569                                return -1;
 570
 571                        if (lock_repo_for_gc(force, &pid))
 572                                return 0;
 573                        if (gc_before_repack())
 574                                return -1;
 575                        delete_tempfile(&pidfile);
 576
 577                        /*
 578                         * failure to daemonize is ok, we'll continue
 579                         * in foreground
 580                         */
 581                        daemonized = !daemonize();
 582                }
 583        } else {
 584                struct string_list keep_pack = STRING_LIST_INIT_NODUP;
 585
 586                if (keep_base_pack != -1) {
 587                        if (keep_base_pack)
 588                                find_base_packs(&keep_pack, 0);
 589                } else if (big_pack_threshold) {
 590                        find_base_packs(&keep_pack, big_pack_threshold);
 591                }
 592
 593                add_repack_all_option(&keep_pack);
 594                string_list_clear(&keep_pack, 0);
 595        }
 596
 597        name = lock_repo_for_gc(force, &pid);
 598        if (name) {
 599                if (auto_gc)
 600                        return 0; /* be quiet on --auto */
 601                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 602                    name, (uintmax_t)pid);
 603        }
 604
 605        if (daemonized) {
 606                hold_lock_file_for_update(&log_lock,
 607                                          git_path("gc.log"),
 608                                          LOCK_DIE_ON_ERROR);
 609                dup2(get_lock_file_fd(&log_lock), 2);
 610                sigchain_push_common(process_log_file_on_signal);
 611                atexit(process_log_file_at_exit);
 612        }
 613
 614        if (gc_before_repack())
 615                return -1;
 616
 617        if (!repository_format_precious_objects) {
 618                close_all_packs(the_repository->objects);
 619                if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 620                        return error(FAILED_RUN, repack.argv[0]);
 621
 622                if (prune_expire) {
 623                        argv_array_push(&prune, prune_expire);
 624                        if (quiet)
 625                                argv_array_push(&prune, "--no-progress");
 626                        if (repository_format_partial_clone)
 627                                argv_array_push(&prune,
 628                                                "--exclude-promisor-objects");
 629                        if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 630                                return error(FAILED_RUN, prune.argv[0]);
 631                }
 632        }
 633
 634        if (prune_worktrees_expire) {
 635                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 636                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 637                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 638        }
 639
 640        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 641                return error(FAILED_RUN, rerere.argv[0]);
 642
 643        report_garbage = report_pack_garbage;
 644        reprepare_packed_git(the_repository);
 645        if (pack_garbage.nr > 0)
 646                clean_pack_garbage();
 647
 648        if (gc_write_commit_graph)
 649                write_commit_graph_reachable(get_object_directory(), 0);
 650
 651        if (auto_gc && too_many_loose_objects())
 652                warning(_("There are too many unreachable loose objects; "
 653                        "run 'git prune' to remove them."));
 654
 655        if (!daemonized)
 656                unlink(git_path("gc.log"));
 657
 658        return 0;
 659}