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git/builtin/gc.c

701 lines
18 KiB

/*
* 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 "strvec.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 strvec pack_refs_cmd = STRVEC_INIT;
static struct strvec reflog = STRVEC_INIT;
static struct strvec repack = STRVEC_INIT;
static struct strvec prune = STRVEC_INIT;
static struct strvec prune_worktrees = STRVEC_INIT;
static struct strvec rerere = STRVEC_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)
{
strvec_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"))
strvec_push(&repack, "-a");
else {
strvec_push(&repack, "-A");
if (prune_expire)
strvec_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)
{
strvec_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 occurred 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.v, RUN_GIT_CMD))
die(FAILED_RUN, pack_refs_cmd.v[0]);
if (prune_reflogs && run_command_v_opt(reflog.v, RUN_GIT_CMD))
die(FAILED_RUN, reflog.v[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);
strvec_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
strvec_pushl(&reflog, "reflog", "expire", "--all", NULL);
strvec_pushl(&repack, "repack", "-d", "-l", NULL);
strvec_pushl(&prune, "prune", "--expire", NULL);
strvec_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
strvec_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) {
strvec_push(&repack, "-f");
if (aggressive_depth > 0)
strvec_pushf(&repack, "--depth=%d", aggressive_depth);
if (aggressive_window > 0)
strvec_pushf(&repack, "--window=%d", aggressive_window);
}
if (quiet)
strvec_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 occurred, 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.v, RUN_GIT_CMD))
die(FAILED_RUN, repack.v[0]);
if (prune_expire) {
strvec_push(&prune, prune_expire);
if (quiet)
strvec_push(&prune, "--no-progress");
if (has_promisor_remote())
strvec_push(&prune,
"--exclude-promisor-objects");
if (run_command_v_opt(prune.v, RUN_GIT_CMD))
die(FAILED_RUN, prune.v[0]);
}
}
if (prune_worktrees_expire) {
strvec_push(&prune_worktrees, prune_worktrees_expire);
if (run_command_v_opt(prune_worktrees.v, RUN_GIT_CMD))
die(FAILED_RUN, prune_worktrees.v[0]);
}
if (run_command_v_opt(rerere.v, RUN_GIT_CMD))
die(FAILED_RUN, rerere.v[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(the_repository->objects->odb,
!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;
}