Andrew's git / gitweb.git / builtin/gc.c
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builtin / gc.con commit memory_limit: use git_env_ulong() to parse GIT_ALLOC_LIMIT (9927d96)
   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 "cache.h"
  15#include "parse-options.h"
  16#include "run-command.h"
  17#include "sigchain.h"
  18#include "argv-array.h"
  19#include "commit.h"
  20
  21#define FAILED_RUN "failed to run %s"
  22
  23static const char * const builtin_gc_usage[] = {
  24        N_("git gc [options]"),
  25        NULL
  26};
  27
  28static int pack_refs = 1;
  29static int prune_reflogs = 1;
  30static int aggressive_depth = 250;
  31static int aggressive_window = 250;
  32static int gc_auto_threshold = 6700;
  33static int gc_auto_pack_limit = 50;
  34static int detach_auto = 1;
  35static const char *prune_expire = "2.weeks.ago";
  36
  37static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  38static struct argv_array reflog = ARGV_ARRAY_INIT;
  39static struct argv_array repack = ARGV_ARRAY_INIT;
  40static struct argv_array prune = ARGV_ARRAY_INIT;
  41static struct argv_array rerere = ARGV_ARRAY_INIT;
  42
  43static char *pidfile;
  44
  45static void remove_pidfile(void)
  46{
  47        if (pidfile)
  48                unlink(pidfile);
  49}
  50
  51static void remove_pidfile_on_signal(int signo)
  52{
  53        remove_pidfile();
  54        sigchain_pop(signo);
  55        raise(signo);
  56}
  57
  58static int gc_config(const char *var, const char *value, void *cb)
  59{
  60        if (!strcmp(var, "gc.packrefs")) {
  61                if (value && !strcmp(value, "notbare"))
  62                        pack_refs = -1;
  63                else
  64                        pack_refs = git_config_bool(var, value);
  65                return 0;
  66        }
  67        if (!strcmp(var, "gc.aggressivewindow")) {
  68                aggressive_window = git_config_int(var, value);
  69                return 0;
  70        }
  71        if (!strcmp(var, "gc.aggressivedepth")) {
  72                aggressive_depth = git_config_int(var, value);
  73                return 0;
  74        }
  75        if (!strcmp(var, "gc.auto")) {
  76                gc_auto_threshold = git_config_int(var, value);
  77                return 0;
  78        }
  79        if (!strcmp(var, "gc.autopacklimit")) {
  80                gc_auto_pack_limit = git_config_int(var, value);
  81                return 0;
  82        }
  83        if (!strcmp(var, "gc.autodetach")) {
  84                detach_auto = git_config_bool(var, value);
  85                return 0;
  86        }
  87        if (!strcmp(var, "gc.pruneexpire")) {
  88                if (value && strcmp(value, "now")) {
  89                        unsigned long now = approxidate("now");
  90                        if (approxidate(value) >= now)
  91                                return error(_("Invalid %s: '%s'"), var, value);
  92                }
  93                return git_config_string(&prune_expire, var, value);
  94        }
  95        return git_default_config(var, value, cb);
  96}
  97
  98static int too_many_loose_objects(void)
  99{
 100        /*
 101         * Quickly check if a "gc" is needed, by estimating how
 102         * many loose objects there are.  Because SHA-1 is evenly
 103         * distributed, we can check only one and get a reasonable
 104         * estimate.
 105         */
 106        char path[PATH_MAX];
 107        const char *objdir = get_object_directory();
 108        DIR *dir;
 109        struct dirent *ent;
 110        int auto_threshold;
 111        int num_loose = 0;
 112        int needed = 0;
 113
 114        if (gc_auto_threshold <= 0)
 115                return 0;
 116
 117        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 118                warning(_("insanely long object directory %.*s"), 50, objdir);
 119                return 0;
 120        }
 121        dir = opendir(path);
 122        if (!dir)
 123                return 0;
 124
 125        auto_threshold = (gc_auto_threshold + 255) / 256;
 126        while ((ent = readdir(dir)) != NULL) {
 127                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 128                    ent->d_name[38] != '\0')
 129                        continue;
 130                if (++num_loose > auto_threshold) {
 131                        needed = 1;
 132                        break;
 133                }
 134        }
 135        closedir(dir);
 136        return needed;
 137}
 138
 139static int too_many_packs(void)
 140{
 141        struct packed_git *p;
 142        int cnt;
 143
 144        if (gc_auto_pack_limit <= 0)
 145                return 0;
 146
 147        prepare_packed_git();
 148        for (cnt = 0, p = packed_git; p; p = p->next) {
 149                if (!p->pack_local)
 150                        continue;
 151                if (p->pack_keep)
 152                        continue;
 153                /*
 154                 * Perhaps check the size of the pack and count only
 155                 * very small ones here?
 156                 */
 157                cnt++;
 158        }
 159        return gc_auto_pack_limit <= cnt;
 160}
 161
 162static void add_repack_all_option(void)
 163{
 164        if (prune_expire && !strcmp(prune_expire, "now"))
 165                argv_array_push(&repack, "-a");
 166        else {
 167                argv_array_push(&repack, "-A");
 168                if (prune_expire)
 169                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 170        }
 171}
 172
 173static int need_to_gc(void)
 174{
 175        /*
 176         * Setting gc.auto to 0 or negative can disable the
 177         * automatic gc.
 178         */
 179        if (gc_auto_threshold <= 0)
 180                return 0;
 181
 182        /*
 183         * If there are too many loose objects, but not too many
 184         * packs, we run "repack -d -l".  If there are too many packs,
 185         * we run "repack -A -d -l".  Otherwise we tell the caller
 186         * there is no need.
 187         */
 188        if (too_many_packs())
 189                add_repack_all_option();
 190        else if (!too_many_loose_objects())
 191                return 0;
 192
 193        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 194                return 0;
 195        return 1;
 196}
 197
 198/* return NULL on success, else hostname running the gc */
 199static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 200{
 201        static struct lock_file lock;
 202        char my_host[128];
 203        struct strbuf sb = STRBUF_INIT;
 204        struct stat st;
 205        uintmax_t pid;
 206        FILE *fp;
 207        int fd;
 208
 209        if (pidfile)
 210                /* already locked */
 211                return NULL;
 212
 213        if (gethostname(my_host, sizeof(my_host)))
 214                strcpy(my_host, "unknown");
 215
 216        fd = hold_lock_file_for_update(&lock, git_path("gc.pid"),
 217                                       LOCK_DIE_ON_ERROR);
 218        if (!force) {
 219                static char locking_host[128];
 220                int should_exit;
 221                fp = fopen(git_path("gc.pid"), "r");
 222                memset(locking_host, 0, sizeof(locking_host));
 223                should_exit =
 224                        fp != NULL &&
 225                        !fstat(fileno(fp), &st) &&
 226                        /*
 227                         * 12 hour limit is very generous as gc should
 228                         * never take that long. On the other hand we
 229                         * don't really need a strict limit here,
 230                         * running gc --auto one day late is not a big
 231                         * problem. --force can be used in manual gc
 232                         * after the user verifies that no gc is
 233                         * running.
 234                         */
 235                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 236                        fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
 237                        /* be gentle to concurrent "gc" on remote hosts */
 238                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 239                if (fp != NULL)
 240                        fclose(fp);
 241                if (should_exit) {
 242                        if (fd >= 0)
 243                                rollback_lock_file(&lock);
 244                        *ret_pid = pid;
 245                        return locking_host;
 246                }
 247        }
 248
 249        strbuf_addf(&sb, "%"PRIuMAX" %s",
 250                    (uintmax_t) getpid(), my_host);
 251        write_in_full(fd, sb.buf, sb.len);
 252        strbuf_release(&sb);
 253        commit_lock_file(&lock);
 254
 255        pidfile = git_pathdup("gc.pid");
 256        sigchain_push_common(remove_pidfile_on_signal);
 257        atexit(remove_pidfile);
 258
 259        return NULL;
 260}
 261
 262static int gc_before_repack(void)
 263{
 264        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 265                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 266
 267        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 268                return error(FAILED_RUN, reflog.argv[0]);
 269
 270        pack_refs = 0;
 271        prune_reflogs = 0;
 272        return 0;
 273}
 274
 275int cmd_gc(int argc, const char **argv, const char *prefix)
 276{
 277        int aggressive = 0;
 278        int auto_gc = 0;
 279        int quiet = 0;
 280        int force = 0;
 281        const char *name;
 282        pid_t pid;
 283
 284        struct option builtin_gc_options[] = {
 285                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 286                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 287                        N_("prune unreferenced objects"),
 288                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 289                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 290                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 291                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 292                OPT_END()
 293        };
 294
 295        if (argc == 2 && !strcmp(argv[1], "-h"))
 296                usage_with_options(builtin_gc_usage, builtin_gc_options);
 297
 298        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 299        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 300        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 301        argv_array_pushl(&prune, "prune", "--expire", NULL );
 302        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 303
 304        git_config(gc_config, NULL);
 305
 306        if (pack_refs < 0)
 307                pack_refs = !is_bare_repository();
 308
 309        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 310                             builtin_gc_usage, 0);
 311        if (argc > 0)
 312                usage_with_options(builtin_gc_usage, builtin_gc_options);
 313
 314        if (aggressive) {
 315                argv_array_push(&repack, "-f");
 316                if (aggressive_depth > 0)
 317                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 318                if (aggressive_window > 0)
 319                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 320        }
 321        if (quiet)
 322                argv_array_push(&repack, "-q");
 323
 324        if (auto_gc) {
 325                /*
 326                 * Auto-gc should be least intrusive as possible.
 327                 */
 328                if (!need_to_gc())
 329                        return 0;
 330                if (!quiet) {
 331                        if (detach_auto)
 332                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 333                        else
 334                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 335                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 336                }
 337                if (detach_auto) {
 338                        if (gc_before_repack())
 339                                return -1;
 340                        /*
 341                         * failure to daemonize is ok, we'll continue
 342                         * in foreground
 343                         */
 344                        daemonize();
 345                }
 346        } else
 347                add_repack_all_option();
 348
 349        name = lock_repo_for_gc(force, &pid);
 350        if (name) {
 351                if (auto_gc)
 352                        return 0; /* be quiet on --auto */
 353                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 354                    name, (uintmax_t)pid);
 355        }
 356
 357        if (gc_before_repack())
 358                return -1;
 359
 360        if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 361                return error(FAILED_RUN, repack.argv[0]);
 362
 363        if (prune_expire) {
 364                argv_array_push(&prune, prune_expire);
 365                if (quiet)
 366                        argv_array_push(&prune, "--no-progress");
 367                if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 368                        return error(FAILED_RUN, prune.argv[0]);
 369        }
 370
 371        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 372                return error(FAILED_RUN, rerere.argv[0]);
 373
 374        if (auto_gc && too_many_loose_objects())
 375                warning(_("There are too many unreachable loose objects; "
 376                        "run 'git prune' to remove them."));
 377
 378        return 0;
 379}