Merge pull request #293: Merge in current ds/maintenance-part-3

This includes all changes from #292, but then also `ds/maintenance-part-3` from upstream. This is _not_ the final maintenance builtin, but is very close. It's time to start making full updates in Scalar that depend on them.

.gitignore

@@ -67,6 +67,7 @@
 /git-filter-branch
 /git-fmt-merge-msg
 /git-for-each-ref
+/git-for-each-repo
 /git-format-patch
 /git-fsck
 /git-fsck-objects

Documentation/config/core.txt

@@ -627,8 +627,8 @@ core.useReplaceRefs::
 
 core.multiPackIndex::
 	Use the multi-pack-index file to track multiple packfiles using a
-	single index. See link:technical/multi-pack-index.html[the
+	single index. See linkgit:git-multi-pack-index[1] for more
-	multi-pack-index design document].
+	information. Defaults to true.
 
 core.gvfs::
 	Enable the features needed for GVFS.  This value can be set to true

Documentation/config/maintenance.txt

@@ -1,3 +1,8 @@
+maintenance.auto::
+	This boolean config option controls whether some commands run
+	`git maintenance run --auto` after doing their normal work. Defaults
+	to true.
+
 maintenance.<task>.enabled::
 	This boolean config option controls whether the maintenance task
 	with name `<task>` is run when no `--task` option is specified to
@@ -5,6 +10,11 @@ maintenance.<task>.enabled::
 	`--task` option exists. By default, only `maintenance.gc.enabled`
 	is true.
 
+maintenance.<task>.schedule::
+	This config option controls whether or not the given `<task>` runs
+	during a `git maintenance run --schedule=<frequency>` command. The
+	value must be one of "hourly", "daily", or "weekly".
+
 maintenance.commit-graph.auto::
 	This integer config option controls how often the `commit-graph` task
 	should be run as part of `git maintenance run --auto`. If zero, then
@@ -14,3 +24,21 @@ maintenance.commit-graph.auto::
 	reachable commits that are not in the commit-graph file is at least
 	the value of `maintenance.commit-graph.auto`. The default value is
 	100.
+
+maintenance.loose-objects.auto::
+	This integer config option controls how often the `loose-objects` task
+	should be run as part of `git maintenance run --auto`. If zero, then
+	the `loose-objects` task will not run with the `--auto` option. A
+	negative value will force the task to run every time. Otherwise, a
+	positive value implies the command should run when the number of
+	loose objects is at least the value of `maintenance.loose-objects.auto`.
+	The default value is 100.
+
+maintenance.incremental-repack.auto::
+	This integer config option controls how often the `incremental-repack`
+	task should be run as part of `git maintenance run --auto`. If zero,
+	then the `incremental-repack` task will not run with the `--auto`
+	option. A negative value will force the task to run every time.
+	Otherwise, a positive value implies the command should run when the
+	number of pack-files not in the multi-pack-index is at least the value
+	of `maintenance.incremental-repack.auto`. The default value is 10.

Documentation/git-for-each-repo.txt

@@ -0,0 +1,59 @@
+git-for-each-repo(1)
+====================
+
+NAME
+----
+git-for-each-repo - Run a Git command on a list of repositories
+
+
+SYNOPSIS
+--------
+[verse]
+'git for-each-repo' --config=<config> [--] <arguments>
+
+
+DESCRIPTION
+-----------
+Run a Git command on a list of repositories. The arguments after the
+known options or `--` indicator are used as the arguments for the Git
+subprocess.
+
+THIS COMMAND IS EXPERIMENTAL. THE BEHAVIOR MAY CHANGE.
+
+For example, we could run maintenance on each of a list of repositories
+stored in a `maintenance.repo` config variable using
+
+-------------
+git for-each-repo --config=maintenance.repo maintenance run
+-------------
+
+This will run `git -C <repo> maintenance run` for each value `<repo>`
+in the multi-valued config variable `maintenance.repo`.
+
+
+OPTIONS
+-------
+--config=<config>::
+	Use the given config variable as a multi-valued list storing
+	absolute path names. Iterate on that list of paths to run
+	the given arguments.
++
+These config values are loaded from system, global, and local Git config,
+as available. If `git for-each-repo` is run in a directory that is not a
+Git repository, then only the system and global config is used.
+
+
+SUBPROCESS BEHAVIOR
+-------------------
+
+If any `git -C <repo> <arguments>` subprocess returns a non-zero exit code,
+then the `git for-each-repo` process returns that exit code without running
+more subprocesses.
+
+Each `git -C <repo> <arguments>` subprocess inherits the standard file
+descriptors `stdin`, `stdout`, and `stderr`.
+
+
+GIT
+---
+Part of the linkgit:git[1] suite

Documentation/git-maintenance.txt

@@ -29,6 +29,30 @@ Git repository.
 SUBCOMMANDS
 -----------
 
+register::
+	Initialize Git config values so any scheduled maintenance will
+	start running on this repository. This adds the repository to the
+	`maintenance.repo` config variable in the current user's global
+	config and enables some recommended configuration values for
+	`maintenance.<task>.schedule`. The tasks that are enabled are safe
+	for running in the background without disrupting foreground
+	processes.
++
+If your repository has no `maintenance.<task>.schedule` configuration
+values set, then Git will use a recommended default schedule that performs
+background maintenance that will not interrupt foreground commands. The
+default schedule is as follows:
++
+* `gc`: disabled.
+* `commit-graph`: hourly.
+* `prefetch`: hourly.
+* `loose-objects`: daily.
+* `incremental-repack`: daily.
++
+`git maintenance register` will also disable foreground maintenance by
+setting `maintenance.auto = false` in the current repository. This config
+setting will remain after a `git maintenance unregister` command.
+
 run::
 	Run one or more maintenance tasks. If one or more `--task` options
 	are specified, then those tasks are run in that order. Otherwise,
@@ -36,6 +60,22 @@ run::
 	config options are true. By default, only `maintenance.gc.enabled`
 	is true.
 
+start::
+	Start running maintenance on the current repository. This performs
+	the same config updates as the `register` subcommand, then updates
+	the background scheduler to run `git maintenance run --scheduled`
+	on an hourly basis.
+
+stop::
+	Halt the background maintenance schedule. The current repository
+	is not removed from the list of maintained repositories, in case
+	the background maintenance is restarted later.
+
+unregister::
+	Remove the current repository from background maintenance. This
+	only removes the repository from the configured list. It does not
+	stop the background maintenance processes from running.
+
 TASKS
 -----
 
@@ -47,6 +87,21 @@ commit-graph::
 	`commit-graph-chain` file. They will be deleted by a later run based
 	on the expiration delay.
 
+prefetch::
+	The `prefetch` task updates the object directory with the latest
+	objects from all registered remotes. For each remote, a `git fetch`
+	command is run. The refmap is custom to avoid updating local or remote
+	branches (those in `refs/heads` or `refs/remotes`). Instead, the
+	remote refs are stored in `refs/prefetch/<remote>/`. Also, tags are
+	not updated.
++
+This is done to avoid disrupting the remote-tracking branches. The end users
+expect these refs to stay unmoved unless they initiate a fetch.  With prefetch
+task, however, the objects necessary to complete a later real fetch would
+already be obtained, so the real fetch would go faster.  In the ideal case,
+it will just become an update to bunch of remote-tracking branches without
+any object transfer.
+
 gc::
 	Clean up unnecessary files and optimize the local repository. "GC"
 	stands for "garbage collection," but this task performs many
@@ -55,6 +110,39 @@ gc::
 	be disruptive in some situations, as it deletes stale data. See
 	linkgit:git-gc[1] for more details on garbage collection in Git.
 
+loose-objects::
+	The `loose-objects` job cleans up loose objects and places them into
+	pack-files. In order to prevent race conditions with concurrent Git
+	commands, it follows a two-step process. First, it deletes any loose
+	objects that already exist in a pack-file; concurrent Git processes
+	will examine the pack-file for the object data instead of the loose
+	object. Second, it creates a new pack-file (starting with "loose-")
+	containing a batch of loose objects. The batch size is limited to 50
+	thousand objects to prevent the job from taking too long on a
+	repository with many loose objects. The `gc` task writes unreachable
+	objects as loose objects to be cleaned up by a later step only if
+	they are not re-added to a pack-file; for this reason it is not
+	advisable to enable both the `loose-objects` and `gc` tasks at the
+	same time.
+
+incremental-repack::
+	The `incremental-repack` job repacks the object directory
+	using the `multi-pack-index` feature. In order to prevent race
+	conditions with concurrent Git commands, it follows a two-step
+	process. First, it calls `git multi-pack-index expire` to delete
+	pack-files unreferenced by the `multi-pack-index` file. Second, it
+	calls `git multi-pack-index repack` to select several small
+	pack-files and repack them into a bigger one, and then update the
+	`multi-pack-index` entries that refer to the small pack-files to
+	refer to the new pack-file. This prepares those small pack-files
+	for deletion upon the next run of `git multi-pack-index expire`.
+	The selection of the small pack-files is such that the expected
+	size of the big pack-file is at least the batch size; see the
+	`--batch-size` option for the `repack` subcommand in
+	linkgit:git-multi-pack-index[1]. The default batch-size is zero,
+	which is a special case that attempts to repack all pack-files
+	into a single pack-file.
+
 OPTIONS
 -------
 --auto::
@@ -62,7 +150,18 @@ OPTIONS
 	only if certain thresholds are met. For example, the `gc` task
 	runs when the number of loose objects exceeds the number stored
 	in the `gc.auto` config setting, or when the number of pack-files
-	exceeds the `gc.autoPackLimit` config setting.
+	exceeds the `gc.autoPackLimit` config setting. Not compatible with
+	the `--schedule` option.
+
+--schedule::
+	When combined with the `run` subcommand, run maintenance tasks
+	only if certain time conditions are met, as specified by the
+	`maintenance.<task>.schedule` config value for each `<task>`.
+	This config value specifies a number of seconds since the last
+	time that task ran, according to the `maintenance.<task>.lastRun`
+	config value. The tasks that are tested are those provided by
+	the `--task=<task>` option(s) or those with
+	`maintenance.<task>.enabled` set to true.
 
 --quiet::
 	Do not report progress or other information over `stderr`.
@@ -74,6 +173,50 @@ OPTIONS
 	`maintenance.<task>.enabled` configured as `true` are considered.
 	See the 'TASKS' section for the list of accepted `<task>` values.
 
+
+TROUBLESHOOTING
+---------------
+The `git maintenance` command is designed to simplify the repository
+maintenance patterns while minimizing user wait time during Git commands.
+A variety of configuration options are available to allow customizing this
+process. The default maintenance options focus on operations that complete
+quickly, even on large repositories.
+
+Users may find some cases where scheduled maintenance tasks do not run as
+frequently as intended. Each `git maintenance run` command takes a lock on
+the repository's object database, and this prevents other concurrent
+`git maintenance run` commands from running on the same repository. Without
+this safeguard, competing processes could leave the repository in an
+unpredictable state.
+
+The background maintenance schedule runs `git maintenance run` processes
+on an hourly basis. Each run executes the "hourly" tasks. At midnight,
+that process also executes the "daily" tasks. At midnight on the first day
+of the week, that process also executes the "weekly" tasks. A single
+process iterates over each registered repository, performing the scheduled
+tasks for that frequency. Depending on the number of registered
+repositories and their sizes, this process may take longer than an hour.
+In this case, multiple `git maintenance run` commands may run on the same
+repository at the same time, colliding on the object database lock. This
+results in one of the two tasks not running.
+
+If you find that some maintenance windows are taking longer than one hour
+to complete, then consider reducing the complexity of your maintenance
+tasks. For example, the `gc` task is much slower than the
+`incremental-repack` task. However, this comes at a cost of a slightly
+larger object database. Consider moving more expensive tasks to be run
+less frequently.
+
+Expert users may consider scheduling their own maintenance tasks using a
+different schedule than is available through `git maintenance start` and
+Git configuration options. These users should be aware of the object
+database lock and how concurrent `git maintenance run` commands behave.
+Further, the `git gc` command should not be combined with
+`git maintenance run` commands. `git gc` modifies the object database
+but does not take the lock in the same way as `git maintenance run`. If
+possible, use `git maintenance run --task=gc` instead of `git gc`.
+
+
 GIT
 ---
 Part of the linkgit:git[1] suite

Makefile

@@ -695,6 +695,7 @@ TEST_BUILTINS_OBJS += test-bloom.o
 TEST_BUILTINS_OBJS += test-chmtime.o
 TEST_BUILTINS_OBJS += test-cmp.o
 TEST_BUILTINS_OBJS += test-config.o
+TEST_BUILTINS_OBJS += test-crontab.o
 TEST_BUILTINS_OBJS += test-ctype.o
 TEST_BUILTINS_OBJS += test-date.o
 TEST_BUILTINS_OBJS += test-delta.o
@@ -1096,6 +1097,7 @@ BUILTIN_OBJS += builtin/fetch-pack.o
 BUILTIN_OBJS += builtin/fetch.o
 BUILTIN_OBJS += builtin/fmt-merge-msg.o
 BUILTIN_OBJS += builtin/for-each-ref.o
+BUILTIN_OBJS += builtin/for-each-repo.o
 BUILTIN_OBJS += builtin/fsck.o
 BUILTIN_OBJS += builtin/gc.o
 BUILTIN_OBJS += builtin/get-tar-commit-id.o

builtin.h

@@ -155,6 +155,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix);
 int cmd_fetch_pack(int argc, const char **argv, const char *prefix);
 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix);
 int cmd_for_each_ref(int argc, const char **argv, const char *prefix);
+int cmd_for_each_repo(int argc, const char **argv, const char *prefix);
 int cmd_format_patch(int argc, const char **argv, const char *prefix);
 int cmd_fsck(int argc, const char **argv, const char *prefix);
 int cmd_gc(int argc, const char **argv, const char *prefix);

builtin/for-each-repo.c

@@ -0,0 +1,58 @@
+#include "cache.h"
+#include "config.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "run-command.h"
+#include "string-list.h"
+
+static const char * const for_each_repo_usage[] = {
+	N_("git for-each-repo --config=<config> <command-args>"),
+	NULL
+};
+
+static int run_command_on_repo(const char *path,
+			       void *cbdata)
+{
+	int i;
+	struct child_process child = CHILD_PROCESS_INIT;
+	struct strvec *args = (struct strvec *)cbdata;
+
+	child.git_cmd = 1;
+	strvec_pushl(&child.args, "-C", path, NULL);
+
+	for (i = 0; i < args->nr; i++)
+		strvec_push(&child.args, args->v[i]);
+
+	return run_command(&child);
+}
+
+int cmd_for_each_repo(int argc, const char **argv, const char *prefix)
+{
+	static const char *config_key = NULL;
+	int i, result = 0;
+	const struct string_list *values;
+	struct strvec args = STRVEC_INIT;
+
+	const struct option options[] = {
+		OPT_STRING(0, "config", &config_key, N_("config"),
+			   N_("config key storing a list of repository paths")),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, options, for_each_repo_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (!config_key)
+		die(_("missing --config=<config>"));
+
+	for (i = 0; i < argc; i++)
+		strvec_push(&args, argv[i]);
+
+	values = repo_config_get_value_multi(the_repository,
+					     config_key);
+
+	for (i = 0; !result && i < values->nr; i++)
+		result = run_command_on_repo(values->items[i].string, &args);
+
+	return result;
+}

builtin/gc.c

@@ -30,6 +30,9 @@
 #include "tree.h"
 #include "promisor-remote.h"
 #include "refs.h"
+#include "remote.h"
+#include "object-store.h"
+#include "exec-cmd.h"
 
 #define FAILED_RUN "failed to run %s"
 
@@ -705,14 +708,51 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 	return 0;
 }
 
-static const char * const builtin_maintenance_run_usage[] = {
+static const char *const builtin_maintenance_run_usage[] = {
-	N_("git maintenance run [--auto] [--[no-]quiet] [--task=<task>]"),
+	N_("git maintenance run [--auto] [--[no-]quiet] [--task=<task>] [--schedule]"),
 	NULL
 };
 
+enum schedule_priority {
+	SCHEDULE_NONE = 0,
+	SCHEDULE_WEEKLY = 1,
+	SCHEDULE_DAILY = 2,
+	SCHEDULE_HOURLY = 3,
+};
+
+static enum schedule_priority parse_schedule(const char *value)
+{
+	if (!value)
+		return SCHEDULE_NONE;
+	if (!strcasecmp(value, "hourly"))
+		return SCHEDULE_HOURLY;
+	if (!strcasecmp(value, "daily"))
+		return SCHEDULE_DAILY;
+	if (!strcasecmp(value, "weekly"))
+		return SCHEDULE_WEEKLY;
+	return SCHEDULE_NONE;
+}
+
+static int maintenance_opt_schedule(const struct option *opt, const char *arg,
+				    int unset)
+{
+	enum schedule_priority *priority = opt->value;
+
+	if (unset)
+		die(_("--no-schedule is not allowed"));
+
+	*priority = parse_schedule(arg);
+
+	if (!*priority)
+		die(_("unrecognized --schedule argument '%s'"), arg);
+
+	return 0;
+}
+
 struct maintenance_run_opts {
 	int auto_flag;
 	int quiet;
+	enum schedule_priority schedule;
 };
 
 /* Remember to update object flag allocation in object.h */
@@ -820,6 +860,51 @@ static int maintenance_task_commit_graph(struct maintenance_run_opts *opts)
 	return 0;
 }
 
+static int fetch_remote(const char *remote, struct maintenance_run_opts *opts)
+{
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.git_cmd = 1;
+	strvec_pushl(&child.args, "fetch", remote, "--prune", "--no-tags",
+		     "--no-write-fetch-head", "--recurse-submodules=no",
+		     "--refmap=", NULL);
+
+	if (opts->quiet)
+		strvec_push(&child.args, "--quiet");
+
+	strvec_pushf(&child.args, "+refs/heads/*:refs/prefetch/%s/*", remote);
+
+	return !!run_command(&child);
+}
+
+static int append_remote(struct remote *remote, void *cbdata)
+{
+	struct string_list *remotes = (struct string_list *)cbdata;
+
+	string_list_append(remotes, remote->name);
+	return 0;
+}
+
+static int maintenance_task_prefetch(struct maintenance_run_opts *opts)
+{
+	int result = 0;
+	struct string_list_item *item;
+	struct string_list remotes = STRING_LIST_INIT_DUP;
+
+	if (for_each_remote(append_remote, &remotes)) {
+		error(_("failed to fill remotes"));
+		result = 1;
+		goto cleanup;
+	}
+
+	for_each_string_list_item(item, &remotes)
+		result |= fetch_remote(item->string, opts);
+
+cleanup:
+	string_list_clear(&remotes, 0);
+	return result;
+}
+
 static int maintenance_task_gc(struct maintenance_run_opts *opts)
 {
 	struct child_process child = CHILD_PROCESS_INIT;
@@ -838,6 +923,268 @@ static int maintenance_task_gc(struct maintenance_run_opts *opts)
 	return run_command(&child);
 }
 
+static int prune_packed(struct maintenance_run_opts *opts)
+{
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.git_cmd = 1;
+	strvec_push(&child.args, "prune-packed");
+
+	if (opts->quiet)
+		strvec_push(&child.args, "--quiet");
+
+	return !!run_command(&child);
+}
+
+struct write_loose_object_data {
+	FILE *in;
+	int count;
+	int batch_size;
+};
+
+static int loose_object_auto_limit = 100;
+
+static int loose_object_count(const struct object_id *oid,
+			       const char *path,
+			       void *data)
+{
+	int *count = (int*)data;
+	if (++(*count) >= loose_object_auto_limit)
+		return 1;
+	return 0;
+}
+
+static int loose_object_auto_condition(void)
+{
+	int count = 0;
+
+	git_config_get_int("maintenance.loose-objects.auto",
+			   &loose_object_auto_limit);
+
+	if (!loose_object_auto_limit)
+		return 0;
+	if (loose_object_auto_limit < 0)
+		return 1;
+
+	return for_each_loose_file_in_objdir(the_repository->objects->odb->path,
+					     loose_object_count,
+					     NULL, NULL, &count);
+}
+
+static int bail_on_loose(const struct object_id *oid,
+			 const char *path,
+			 void *data)
+{
+	return 1;
+}
+
+static int write_loose_object_to_stdin(const struct object_id *oid,
+				       const char *path,
+				       void *data)
+{
+	struct write_loose_object_data *d = (struct write_loose_object_data *)data;
+
+	fprintf(d->in, "%s\n", oid_to_hex(oid));
+
+	return ++(d->count) > d->batch_size;
+}
+
+static int pack_loose(struct maintenance_run_opts *opts)
+{
+	struct repository *r = the_repository;
+	int result = 0;
+	struct write_loose_object_data data;
+	struct child_process pack_proc = CHILD_PROCESS_INIT;
+
+	/*
+	 * Do not start pack-objects process
+	 * if there are no loose objects.
+	 */
+	if (!for_each_loose_file_in_objdir(r->objects->odb->path,
+					   bail_on_loose,
+					   NULL, NULL, NULL))
+		return 0;
+
+	pack_proc.git_cmd = 1;
+
+	strvec_push(&pack_proc.args, "pack-objects");
+	if (opts->quiet)
+		strvec_push(&pack_proc.args, "--quiet");
+	strvec_pushf(&pack_proc.args, "%s/pack/loose", r->objects->odb->path);
+
+	pack_proc.in = -1;
+
+	if (start_command(&pack_proc)) {
+		error(_("failed to start 'git pack-objects' process"));
+		return 1;
+	}
+
+	data.in = xfdopen(pack_proc.in, "w");
+	data.count = 0;
+	data.batch_size = 50000;
+
+	for_each_loose_file_in_objdir(r->objects->odb->path,
+				      write_loose_object_to_stdin,
+				      NULL,
+				      NULL,
+				      &data);
+
+	fclose(data.in);
+
+	if (finish_command(&pack_proc)) {
+		error(_("failed to finish 'git pack-objects' process"));
+		result = 1;
+	}
+
+	return result;
+}
+
+static int maintenance_task_loose_objects(struct maintenance_run_opts *opts)
+{
+	return prune_packed(opts) || pack_loose(opts);
+}
+
+static int incremental_repack_auto_condition(void)
+{
+	struct packed_git *p;
+	int enabled;
+	int incremental_repack_auto_limit = 10;
+	int count = 0;
+
+	if (git_config_get_bool("core.multiPackIndex", &enabled) ||
+	    !enabled)
+		return 0;
+
+	git_config_get_int("maintenance.incremental-repack.auto",
+			   &incremental_repack_auto_limit);
+
+	if (!incremental_repack_auto_limit)
+		return 0;
+	if (incremental_repack_auto_limit < 0)
+		return 1;
+
+	for (p = get_packed_git(the_repository);
+	     count < incremental_repack_auto_limit && p;
+	     p = p->next) {
+		if (!p->multi_pack_index)
+			count++;
+	}
+
+	return count >= incremental_repack_auto_limit;
+}
+
+static int multi_pack_index_write(struct maintenance_run_opts *opts)
+{
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.git_cmd = 1;
+	strvec_pushl(&child.args, "multi-pack-index", "write", NULL);
+
+	if (opts->quiet)
+		strvec_push(&child.args, "--no-progress");
+
+	if (run_command(&child))
+		return error(_("failed to write multi-pack-index"));
+
+	return 0;
+}
+
+static int multi_pack_index_expire(struct maintenance_run_opts *opts)
+{
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.git_cmd = 1;
+	strvec_pushl(&child.args, "multi-pack-index", "expire", NULL);
+
+	if (opts->quiet)
+		strvec_push(&child.args, "--no-progress");
+
+	close_object_store(the_repository->objects);
+
+	if (run_command(&child))
+		return error(_("'git multi-pack-index expire' failed"));
+
+	return 0;
+}
+
+#define TWO_GIGABYTES (INT32_MAX)
+
+static off_t get_auto_pack_size(void)
+{
+	/*
+	 * The "auto" value is special: we optimize for
+	 * one large pack-file (i.e. from a clone) and
+	 * expect the rest to be small and they can be
+	 * repacked quickly.
+	 *
+	 * The strategy we select here is to select a
+	 * size that is one more than the second largest
+	 * pack-file. This ensures that we will repack
+	 * at least two packs if there are three or more
+	 * packs.
+	 */
+	off_t max_size = 0;
+	off_t second_largest_size = 0;
+	off_t result_size;
+	struct packed_git *p;
+	struct repository *r = the_repository;
+
+	reprepare_packed_git(r);
+	for (p = get_all_packs(r); p; p = p->next) {
+		if (p->pack_size > max_size) {
+			second_largest_size = max_size;
+			max_size = p->pack_size;
+		} else if (p->pack_size > second_largest_size)
+			second_largest_size = p->pack_size;
+	}
+
+	result_size = second_largest_size + 1;
+
+	/* But limit ourselves to a batch size of 2g */
+	if (result_size > TWO_GIGABYTES)
+		result_size = TWO_GIGABYTES;
+
+	return result_size;
+}
+
+static int multi_pack_index_repack(struct maintenance_run_opts *opts)
+{
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	child.git_cmd = 1;
+	strvec_pushl(&child.args, "multi-pack-index", "repack", NULL);
+
+	if (opts->quiet)
+		strvec_push(&child.args, "--no-progress");
+
+	strvec_pushf(&child.args, "--batch-size=%"PRIuMAX,
+				  (uintmax_t)get_auto_pack_size());
+
+	close_object_store(the_repository->objects);
+
+	if (run_command(&child))
+		return error(_("'git multi-pack-index repack' failed"));
+
+	return 0;
+}
+
+static int maintenance_task_incremental_repack(struct maintenance_run_opts *opts)
+{
+	prepare_repo_settings(the_repository);
+	if (!the_repository->settings.core_multi_pack_index) {
+		warning(_("skipping incremental-repack task because core.multiPackIndex is disabled"));
+		return 0;
+	}
+
+	if (multi_pack_index_write(opts))
+		return 1;
+	if (multi_pack_index_expire(opts))
+		return 1;
+	if (multi_pack_index_repack(opts))
+		return 1;
+	return 0;
+}
+
 typedef int maintenance_task_fn(struct maintenance_run_opts *opts);
 
 /*
@@ -853,11 +1200,16 @@ struct maintenance_task {
 	maintenance_auto_fn *auto_condition;
 	unsigned enabled:1;
 
+	enum schedule_priority schedule;
+
 	/* -1 if not selected. */
 	int selected_order;
 };
 
 enum maintenance_task_label {
+	TASK_PREFETCH,
+	TASK_LOOSE_OBJECTS,
+	TASK_INCREMENTAL_REPACK,
 	TASK_GC,
 	TASK_COMMIT_GRAPH,
 
@@ -866,6 +1218,20 @@ enum maintenance_task_label {
 };
 
 static struct maintenance_task tasks[] = {
+	[TASK_PREFETCH] = {
+		"prefetch",
+		maintenance_task_prefetch,
+	},
+	[TASK_LOOSE_OBJECTS] = {
+		"loose-objects",
+		maintenance_task_loose_objects,
+		loose_object_auto_condition,
+	},
+	[TASK_INCREMENTAL_REPACK] = {
+		"incremental-repack",
+		maintenance_task_incremental_repack,
+		incremental_repack_auto_condition,
+	},
 	[TASK_GC] = {
 		"gc",
 		maintenance_task_gc,
@@ -889,6 +1255,59 @@ static int compare_tasks_by_selection(const void *a_, const void *b_)
 	return b->selected_order - a->selected_order;
 }
 
+static int has_schedule_config(void)
+{
+	int i, found = 0;
+	struct strbuf config_name = STRBUF_INIT;
+	size_t prefix;
+
+	strbuf_addstr(&config_name, "maintenance.");
+	prefix = config_name.len;
+
+	for (i = 0; !found && i < TASK__COUNT; i++) {
+		char *value;
+
+		strbuf_setlen(&config_name, prefix);
+		strbuf_addf(&config_name, "%s.schedule", tasks[i].name);
+
+		if (!git_config_get_string(config_name.buf, &value)) {
+			found = 1;
+			FREE_AND_NULL(value);
+		}
+
+		strbuf_setlen(&config_name, prefix);
+		strbuf_addf(&config_name, "%s.enabled", tasks[i].name);
+
+		if (!git_config_get_string(config_name.buf, &value)) {
+			found = 1;
+			FREE_AND_NULL(value);
+		}
+	}
+
+	strbuf_release(&config_name);
+	return found;
+}
+
+static void set_recommended_schedule(void)
+{
+	if (has_schedule_config())
+		return;
+
+	tasks[TASK_GC].enabled = 0;
+
+	tasks[TASK_PREFETCH].enabled = 1;
+	tasks[TASK_PREFETCH].schedule = SCHEDULE_HOURLY;
+
+	tasks[TASK_COMMIT_GRAPH].enabled = 1;
+	tasks[TASK_COMMIT_GRAPH].schedule = SCHEDULE_HOURLY;
+
+	tasks[TASK_LOOSE_OBJECTS].enabled = 1;
+	tasks[TASK_LOOSE_OBJECTS].schedule = SCHEDULE_DAILY;
+
+	tasks[TASK_INCREMENTAL_REPACK].enabled = 1;
+	tasks[TASK_INCREMENTAL_REPACK].schedule = SCHEDULE_DAILY;
+}
+
 static int maintenance_run_tasks(struct maintenance_run_opts *opts)
 {
 	int i, found_selected = 0;
@@ -918,6 +1337,8 @@ static int maintenance_run_tasks(struct maintenance_run_opts *opts)
 
 	if (found_selected)
 		QSORT(tasks, TASK__COUNT, compare_tasks_by_selection);
+	else if (opts->schedule != SCHEDULE_NONE)
+		set_recommended_schedule();
 
 	for (i = 0; i < TASK__COUNT; i++) {
 		if (found_selected && tasks[i].selected_order < 0)
@@ -931,6 +1352,9 @@ static int maintenance_run_tasks(struct maintenance_run_opts *opts)
 		     !tasks[i].auto_condition()))
 			continue;
 
+		if (opts->schedule && tasks[i].schedule < opts->schedule)
+			continue;
+
 		trace2_region_enter("maintenance", tasks[i].name, r);
 		if (tasks[i].fn(opts)) {
 			error(_("task '%s' failed"), tasks[i].name);
@@ -951,13 +1375,23 @@ static void initialize_task_config(void)
 
 	for (i = 0; i < TASK__COUNT; i++) {
 		int config_value;
+		char *config_str;
 
-		strbuf_setlen(&config_name, 0);
+		strbuf_reset(&config_name);
 		strbuf_addf(&config_name, "maintenance.%s.enabled",
 			    tasks[i].name);
 
 		if (!git_config_get_bool(config_name.buf, &config_value))
 			tasks[i].enabled = config_value;
+
+		strbuf_reset(&config_name);
+		strbuf_addf(&config_name, "maintenance.%s.schedule",
+			    tasks[i].name);
+
+		if (!git_config_get_string(config_name.buf, &config_str)) {
+			tasks[i].schedule = parse_schedule(config_str);
+			free(config_str);
+		}
 	}
 
 	strbuf_release(&config_name);
@@ -1001,6 +1435,9 @@ static int maintenance_run(int argc, const char **argv, const char *prefix)
 	struct option builtin_maintenance_run_options[] = {
 		OPT_BOOL(0, "auto", &opts.auto_flag,
 			 N_("run tasks based on the state of the repository")),
+		OPT_CALLBACK(0, "schedule", &opts.schedule, N_("frequency"),
+			     N_("run tasks based on frequency"),
+			     maintenance_opt_schedule),
 		OPT_BOOL(0, "quiet", &opts.quiet,
 			 N_("do not report progress or other information over stderr")),
 		OPT_CALLBACK_F(0, "task", NULL, N_("task"),
@@ -1021,13 +1458,187 @@ static int maintenance_run(int argc, const char **argv, const char *prefix)
 			     builtin_maintenance_run_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 
+	if (opts.auto_flag && opts.schedule)
+		die(_("use at most one of --auto and --schedule=<frequency>"));
+
 	if (argc != 0)
 		usage_with_options(builtin_maintenance_run_usage,
 				   builtin_maintenance_run_options);
 	return maintenance_run_tasks(&opts);
 }
 
-static const char builtin_maintenance_usage[] = N_("git maintenance run [<options>]");
+static int maintenance_register(void)
+{
+	struct child_process config_set = CHILD_PROCESS_INIT;
+	struct child_process config_get = CHILD_PROCESS_INIT;
+
+	/* There is no current repository, so skip registering it */
+	if (!the_repository || !the_repository->gitdir)
+		return 0;
+
+	/* Disable foreground maintenance */
+	git_config_set("maintenance.auto", "false");
+
+	config_get.git_cmd = 1;
+	strvec_pushl(&config_get.args, "config", "--global", "--get", "maintenance.repo",
+		     the_repository->worktree ? the_repository->worktree
+					      : the_repository->gitdir,
+			 NULL);
+	config_get.out = -1;
+
+	if (start_command(&config_get))
+		return error(_("failed to run 'git config'"));
+
+	/* We already have this value in our config! */
+	if (!finish_command(&config_get))
+		return 0;
+
+	config_set.git_cmd = 1;
+	strvec_pushl(&config_set.args, "config", "--add", "--global", "maintenance.repo",
+		     the_repository->worktree ? the_repository->worktree
+					      : the_repository->gitdir,
+		     NULL);
+
+	return run_command(&config_set);
+}
+
+static int maintenance_unregister(void)
+{
+	struct child_process config_unset = CHILD_PROCESS_INIT;
+
+	if (!the_repository || !the_repository->gitdir)
+		return error(_("no current repository to unregister"));
+
+	config_unset.git_cmd = 1;
+	strvec_pushl(&config_unset.args, "config", "--global", "--unset",
+		     "maintenance.repo",
+		     the_repository->worktree ? the_repository->worktree
+					      : the_repository->gitdir,
+		     NULL);
+
+	return run_command(&config_unset);
+}
+
+#define BEGIN_LINE "# BEGIN GIT MAINTENANCE SCHEDULE"
+#define END_LINE "# END GIT MAINTENANCE SCHEDULE"
+
+static int update_background_schedule(int run_maintenance)
+{
+	int result = 0;
+	int in_old_region = 0;
+	struct child_process crontab_list = CHILD_PROCESS_INIT;
+	struct child_process crontab_edit = CHILD_PROCESS_INIT;
+	FILE *cron_list, *cron_in;
+	const char *crontab_name;
+	struct strbuf line = STRBUF_INIT;
+	struct lock_file lk;
+	char *lock_path = xstrfmt("%s/schedule", the_repository->objects->odb->path);
+
+	if (hold_lock_file_for_update(&lk, lock_path, LOCK_NO_DEREF) < 0)
+		return error(_("another process is scheduling background maintenance"));
+
+	crontab_name = getenv("GIT_TEST_CRONTAB");
+	if (!crontab_name)
+		crontab_name = "crontab";
+
+	strvec_split(&crontab_list.args, crontab_name);
+	strvec_push(&crontab_list.args, "-l");
+	crontab_list.in = -1;
+	crontab_list.out = dup(lk.tempfile->fd);
+	crontab_list.git_cmd = 0;
+
+	if (start_command(&crontab_list)) {
+		result = error(_("failed to run 'crontab -l'; your system might not support 'cron'"));
+		goto cleanup;
+	}
+
+	/* Ignore exit code, as an empty crontab will return error. */
+	finish_command(&crontab_list);
+
+	/*
+	 * Read from the .lock file, filtering out the old
+	 * schedule while appending the new schedule.
+	 */
+	cron_list = fdopen(lk.tempfile->fd, "r");
+	rewind(cron_list);
+
+	strvec_split(&crontab_edit.args, crontab_name);
+	crontab_edit.in = -1;
+	crontab_edit.git_cmd = 0;
+
+	if (start_command(&crontab_edit)) {
+		result = error(_("failed to run 'crontab'; your system might not support 'cron'"));
+		goto cleanup;
+	}
+
+	cron_in = fdopen(crontab_edit.in, "w");
+	if (!cron_in) {
+		result = error(_("failed to open stdin of 'crontab'"));
+		goto done_editing;
+	}
+
+	while (!strbuf_getline_lf(&line, cron_list)) {
+		if (!in_old_region && !strcmp(line.buf, BEGIN_LINE))
+			in_old_region = 1;
+		if (in_old_region)
+			continue;
+		fprintf(cron_in, "%s\n", line.buf);
+		if (in_old_region && !strcmp(line.buf, END_LINE))
+			in_old_region = 0;
+	}
+
+	if (run_maintenance) {
+		struct strbuf line_format = STRBUF_INIT;
+		const char *exec_path = git_exec_path();
+
+		fprintf(cron_in, "%s\n", BEGIN_LINE);
+		fprintf(cron_in,
+			"# The following schedule was created by Git\n");
+		fprintf(cron_in, "# Any edits made in this region might be\n");
+		fprintf(cron_in,
+			"# replaced in the future by a Git command.\n\n");
+
+		strbuf_addf(&line_format,
+			    "%%s %%s * * %%s \"%s/git\" --exec-path=\"%s\" for-each-repo --config=maintenance.repo maintenance run --schedule=%%s\n",
+			    exec_path, exec_path);
+		fprintf(cron_in, line_format.buf, "0", "1-23", "*", "hourly");
+		fprintf(cron_in, line_format.buf, "0", "0", "1-6", "daily");
+		fprintf(cron_in, line_format.buf, "0", "0", "0", "weekly");
+		strbuf_release(&line_format);
+
+		fprintf(cron_in, "\n%s\n", END_LINE);
+	}
+
+	fflush(cron_in);
+	fclose(cron_in);
+	close(crontab_edit.in);
+
+done_editing:
+	if (finish_command(&crontab_edit)) {
+		result = error(_("'crontab' died"));
+		goto cleanup;
+	}
+	fclose(cron_list);
+
+cleanup:
+	rollback_lock_file(&lk);
+	return result;
+}
+
+static int maintenance_start(void)
+{
+	if (maintenance_register())
+		warning(_("failed to add repo to global config"));
+
+	return update_background_schedule(1);
+}
+
+static int maintenance_stop(void)
+{
+	return update_background_schedule(0);
+}
+
+static const char builtin_maintenance_usage[] =	N_("git maintenance <subcommand> [<options>]");
 
 int cmd_maintenance(int argc, const char **argv, const char *prefix)
 {
@@ -1037,6 +1648,14 @@ int cmd_maintenance(int argc, const char **argv, const char *prefix)
 
 	if (!strcmp(argv[1], "run"))
 		return maintenance_run(argc - 1, argv + 1, prefix);
+	if (!strcmp(argv[1], "start"))
+		return maintenance_start();
+	if (!strcmp(argv[1], "stop"))
+		return maintenance_stop();
+	if (!strcmp(argv[1], "register"))
+		return maintenance_register();
+	if (!strcmp(argv[1], "unregister"))
+		return maintenance_unregister();
 
 	die(_("invalid subcommand: %s"), argv[1]);
 }

command-list.txt

@@ -94,6 +94,7 @@ git-fetch-pack                          synchingrepositories
 git-filter-branch                       ancillarymanipulators
 git-fmt-merge-msg                       purehelpers
 git-for-each-ref                        plumbinginterrogators
+git-for-each-repo                       plumbinginterrogators
 git-format-patch                        mainporcelain
 git-fsck                                ancillaryinterrogators          complete
 git-gc                                  mainporcelain

git.c

@@ -585,6 +585,7 @@ static struct cmd_struct commands[] = {
 	{ "fetch-pack", cmd_fetch_pack, RUN_SETUP | NO_PARSEOPT },
 	{ "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 	{ "for-each-ref", cmd_for_each_ref, RUN_SETUP },
+	{ "for-each-repo", cmd_for_each_repo, RUN_SETUP_GENTLY },
 	{ "format-patch", cmd_format_patch, RUN_SETUP },
 	{ "fsck", cmd_fsck, RUN_SETUP | BLOCK_ON_GVFS_REPO},
 	{ "fsck-objects", cmd_fsck, RUN_SETUP },

midx.c

@@ -10,6 +10,7 @@
 #include "progress.h"
 #include "trace2.h"
 #include "run-command.h"
+#include "repository.h"
 
 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
 #define MIDX_VERSION 1
@@ -398,15 +399,9 @@ int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, i
 {
 	struct multi_pack_index *m;
 	struct multi_pack_index *m_search;
-	int config_value;
-	static int env_value = -1;
 
-	if (env_value < 0)
+	prepare_repo_settings(r);
-		env_value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
+	if (!r->settings.core_multi_pack_index)
-
-	if (!env_value &&
-	    (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
-	    !config_value))
 		return 0;
 
 	for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
@@ -850,7 +845,7 @@ static int write_midx_internal(const char *object_dir, struct multi_pack_index *
 
 	packs.pack_paths_checked = 0;
 	if (flags & MIDX_PROGRESS)
-		packs.progress = start_progress(_("Adding packfiles to multi-pack-index"), 0);
+		packs.progress = start_delayed_progress(_("Adding packfiles to multi-pack-index"), 0);
 	else
 		packs.progress = NULL;
 
@@ -987,7 +982,7 @@ static int write_midx_internal(const char *object_dir, struct multi_pack_index *
 	}
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_progress(_("Writing chunks to multi-pack-index"),
+		progress = start_delayed_progress(_("Writing chunks to multi-pack-index"),
 					  num_chunks);
 	for (i = 0; i < num_chunks; i++) {
 		if (written != chunk_offsets[i])
@@ -1129,7 +1124,7 @@ int verify_midx_file(struct repository *r, const char *object_dir, unsigned flag
 	}
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_progress(_("Looking for referenced packfiles"),
+		progress = start_delayed_progress(_("Looking for referenced packfiles"),
 					  m->num_packs);
 	for (i = 0; i < m->num_packs; i++) {
 		if (prepare_midx_pack(r, m, i))
@@ -1250,7 +1245,7 @@ int expire_midx_packs(struct repository *r, const char *object_dir, unsigned fla
 	count = xcalloc(m->num_packs, sizeof(uint32_t));
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_progress(_("Counting referenced objects"),
+		progress = start_delayed_progress(_("Counting referenced objects"),
 					  m->num_objects);
 	for (i = 0; i < m->num_objects; i++) {
 		int pack_int_id = nth_midxed_pack_int_id(m, i);
@@ -1260,7 +1255,7 @@ int expire_midx_packs(struct repository *r, const char *object_dir, unsigned fla
 	stop_progress(&progress);
 
 	if (flags & MIDX_PROGRESS)
-		progress = start_progress(_("Finding and deleting unreferenced packfiles"),
+		progress = start_delayed_progress(_("Finding and deleting unreferenced packfiles"),
 					  m->num_packs);
 	for (i = 0; i < m->num_packs; i++) {
 		char *pack_name;

repo-settings.c

@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "config.h"
 #include "repository.h"
+#include "midx.h"
 
 #define UPDATE_DEFAULT_BOOL(s,v) do { if (s == -1) { s = v; } } while(0)
 
@@ -52,6 +53,11 @@ void prepare_repo_settings(struct repository *r)
 		r->settings.pack_use_sparse = value;
 	UPDATE_DEFAULT_BOOL(r->settings.pack_use_sparse, 1);
 
+	value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
+	if (value || !repo_config_get_bool(r, "core.multipackindex", &value))
+		r->settings.core_multi_pack_index = value;
+	UPDATE_DEFAULT_BOOL(r->settings.core_multi_pack_index, 1);
+
 	if (!repo_config_get_bool(r, "feature.manyfiles", &value) && value) {
 		UPDATE_DEFAULT_BOOL(r->settings.index_version, 4);
 		UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_WRITE);

repository.h

@@ -39,6 +39,8 @@ struct repo_settings {
 
 	int pack_use_sparse;
 	enum fetch_negotiation_setting fetch_negotiation_algorithm;
+
+	int core_multi_pack_index;
 };
 
 struct repository {

run-command.c

@@ -1951,8 +1951,13 @@ int run_processes_parallel_tr2(int n, get_next_task_fn get_next_task,
 
 int run_auto_maintenance(int quiet)
 {
+	int enabled;
 	struct child_process maint = CHILD_PROCESS_INIT;
 
+	if (!git_config_get_bool("maintenance.auto", &enabled) &&
+	    !enabled)
+		return 0;
+
 	maint.git_cmd = 1;
 	strvec_pushl(&maint.args, "maintenance", "run", "--auto", NULL);
 	strvec_push(&maint.args, quiet ? "--quiet" : "--no-quiet");

t/helper/test-crontab.c

@@ -0,0 +1,35 @@
+#include "test-tool.h"
+#include "cache.h"
+
+/*
+ * Usage: test-tool cron <file> [-l]
+ *
+ * If -l is specified, then write the contents of <file> to stdout.
+ * Otherwise, write from stdin into <file>.
+ */
+int cmd__crontab(int argc, const char **argv)
+{
+	int a;
+	FILE *from, *to;
+
+	if (argc == 3 && !strcmp(argv[2], "-l")) {
+		from = fopen(argv[1], "r");
+		if (!from)
+			return 0;
+		to = stdout;
+	} else if (argc == 2) {
+		from = stdin;
+		to = fopen(argv[1], "w");
+	} else
+		return error("unknown arguments");
+
+	while ((a = fgetc(from)) != EOF)
+		fputc(a, to);
+
+	if (argc == 3)
+		fclose(from);
+	else
+		fclose(to);
+
+	return 0;
+}

t/helper/test-tool.c

@@ -19,6 +19,7 @@ static struct test_cmd cmds[] = {
 	{ "chmtime", cmd__chmtime },
 	{ "cmp", cmd__cmp },
 	{ "config", cmd__config },
+	{ "crontab", cmd__crontab },
 	{ "ctype", cmd__ctype },
 	{ "date", cmd__date },
 	{ "delta", cmd__delta },

t/helper/test-tool.h

@@ -9,6 +9,7 @@ int cmd__bloom(int argc, const char **argv);
 int cmd__chmtime(int argc, const char **argv);
 int cmd__cmp(int argc, const char **argv);
 int cmd__config(int argc, const char **argv);
+int cmd__crontab(int argc, const char **argv);
 int cmd__ctype(int argc, const char **argv);
 int cmd__date(int argc, const char **argv);
 int cmd__delta(int argc, const char **argv);

t/t0068-for-each-repo.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+
+test_description='git for-each-repo builtin'
+
+. ./test-lib.sh
+
+test_expect_success 'run based on configured value' '
+	git init one &&
+	git init two &&
+	git init three &&
+	git -C two commit --allow-empty -m "DID NOT RUN" &&
+	git config run.key "$TRASH_DIRECTORY/one" &&
+	git config --add run.key "$TRASH_DIRECTORY/three" &&
+	git for-each-repo --config=run.key commit --allow-empty -m "ran" &&
+	git -C one log -1 --pretty=format:%s >message &&
+	grep ran message &&
+	git -C two log -1 --pretty=format:%s >message &&
+	! grep ran message &&
+	git -C three log -1 --pretty=format:%s >message &&
+	grep ran message &&
+	git for-each-repo --config=run.key -- commit --allow-empty -m "ran again" &&
+	git -C one log -1 --pretty=format:%s >message &&
+	grep again message &&
+	git -C two log -1 --pretty=format:%s >message &&
+	! grep again message &&
+	git -C three log -1 --pretty=format:%s >message &&
+	grep again message
+'
+
+test_done

t/t5319-multi-pack-index.sh

@@ -3,6 +3,7 @@
 test_description='multi-pack-indexes'
 . ./test-lib.sh
 
+GIT_TEST_MULTI_PACK_INDEX=0
 objdir=.git/objects
 
 HASH_LEN=$(test_oid rawsz)
@@ -173,12 +174,12 @@ test_expect_success 'write progress off for redirected stderr' '
 '
 
 test_expect_success 'write force progress on for stderr' '
-	git multi-pack-index --object-dir=$objdir --progress write 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --progress write 2>err &&
 	test_file_not_empty err
 '
 
 test_expect_success 'write with the --no-progress option' '
-	git multi-pack-index --object-dir=$objdir --no-progress write 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --no-progress write 2>err &&
 	test_line_count = 0 err
 '
 
@@ -368,17 +369,17 @@ test_expect_success 'git-fsck incorrect offset' '
 '
 
 test_expect_success 'repack progress off for redirected stderr' '
-	git multi-pack-index --object-dir=$objdir repack 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir repack 2>err &&
 	test_line_count = 0 err
 '
 
 test_expect_success 'repack force progress on for stderr' '
-	git multi-pack-index --object-dir=$objdir --progress repack 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --progress repack 2>err &&
 	test_file_not_empty err
 '
 
 test_expect_success 'repack with the --no-progress option' '
-	git multi-pack-index --object-dir=$objdir --no-progress repack 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --no-progress repack 2>err &&
 	test_line_count = 0 err
 '
 
@@ -562,7 +563,7 @@ test_expect_success 'expire progress off for redirected stderr' '
 test_expect_success 'expire force progress on for stderr' '
 	(
 		cd dup &&
-		git multi-pack-index --progress expire 2>err &&
+		GIT_PROGRESS_DELAY=0 git multi-pack-index --progress expire 2>err &&
 		test_file_not_empty err
 	)
 '
@@ -570,7 +571,7 @@ test_expect_success 'expire force progress on for stderr' '
 test_expect_success 'expire with the --no-progress option' '
 	(
 		cd dup &&
-		git multi-pack-index --no-progress expire 2>err &&
+		GIT_PROGRESS_DELAY=0 git multi-pack-index --no-progress expire 2>err &&
 		test_line_count = 0 err
 	)
 '

t/t7900-maintenance.sh

@@ -5,10 +5,11 @@ test_description='git maintenance builtin'
 . ./test-lib.sh
 
 GIT_TEST_COMMIT_GRAPH=0
+GIT_TEST_MULTI_PACK_INDEX=0
 
 test_expect_success 'help text' '
 	test_expect_code 129 git maintenance -h 2>err &&
-	test_i18ngrep "usage: git maintenance run" err &&
+	test_i18ngrep "usage: git maintenance <subcommand>" err &&
 	test_expect_code 128 git maintenance barf 2>err &&
 	test_i18ngrep "invalid subcommand: barf" err &&
 	test_expect_code 129 git maintenance 2>err &&
@@ -27,6 +28,19 @@ test_expect_success 'run [--auto|--quiet]' '
 	test_subcommand git gc --no-quiet <run-no-quiet.txt
 '
 
+test_expect_success 'maintenance.auto config option' '
+	GIT_TRACE2_EVENT="$(pwd)/default" git commit --quiet --allow-empty -m 1 &&
+	test_subcommand git maintenance run --auto --quiet <default &&
+	GIT_TRACE2_EVENT="$(pwd)/true" \
+		git -c maintenance.auto=true \
+		commit --quiet --allow-empty -m 2 &&
+	test_subcommand git maintenance run --auto --quiet  <true &&
+	GIT_TRACE2_EVENT="$(pwd)/false" \
+		git -c maintenance.auto=false \
+		commit --quiet --allow-empty -m 3 &&
+	test_subcommand ! git maintenance run --auto --quiet  <false
+'
+
 test_expect_success 'maintenance.<task>.enabled' '
 	git config maintenance.gc.enabled false &&
 	git config maintenance.commit-graph.enabled true &&
@@ -62,4 +76,274 @@ test_expect_success 'run --task duplicate' '
 	test_i18ngrep "cannot be selected multiple times" err
 '
 
+test_expect_success 'run --task=prefetch with no remotes' '
+	git maintenance run --task=prefetch 2>err &&
+	test_must_be_empty err
+'
+
+test_expect_success 'prefetch multiple remotes' '
+	git clone . clone1 &&
+	git clone . clone2 &&
+	git remote add remote1 "file://$(pwd)/clone1" &&
+	git remote add remote2 "file://$(pwd)/clone2" &&
+	git -C clone1 switch -c one &&
+	git -C clone2 switch -c two &&
+	test_commit -C clone1 one &&
+	test_commit -C clone2 two &&
+	GIT_TRACE2_EVENT="$(pwd)/run-prefetch.txt" git maintenance run --task=prefetch 2>/dev/null &&
+	fetchargs="--prune --no-tags --no-write-fetch-head --recurse-submodules=no --refmap= --quiet" &&
+	test_subcommand git fetch remote1 $fetchargs +refs/heads/\\*:refs/prefetch/remote1/\\* <run-prefetch.txt &&
+	test_subcommand git fetch remote2 $fetchargs +refs/heads/\\*:refs/prefetch/remote2/\\* <run-prefetch.txt &&
+	test_path_is_missing .git/refs/remotes &&
+	git log prefetch/remote1/one &&
+	git log prefetch/remote2/two &&
+	git fetch --all &&
+	test_cmp_rev refs/remotes/remote1/one refs/prefetch/remote1/one &&
+	test_cmp_rev refs/remotes/remote2/two refs/prefetch/remote2/two
+'
+
+test_expect_success 'loose-objects task' '
+	# Repack everything so we know the state of the object dir
+	git repack -adk &&
+
+	# Hack to stop maintenance from running during "git commit"
+	echo in use >.git/objects/maintenance.lock &&
+
+	# Assuming that "git commit" creates at least one loose object
+	test_commit create-loose-object &&
+	rm .git/objects/maintenance.lock &&
+
+	ls .git/objects >obj-dir-before &&
+	test_file_not_empty obj-dir-before &&
+	ls .git/objects/pack/*.pack >packs-before &&
+	test_line_count = 1 packs-before &&
+
+	# The first run creates a pack-file
+	# but does not delete loose objects.
+	git maintenance run --task=loose-objects &&
+	ls .git/objects >obj-dir-between &&
+	test_cmp obj-dir-before obj-dir-between &&
+	ls .git/objects/pack/*.pack >packs-between &&
+	test_line_count = 2 packs-between &&
+	ls .git/objects/pack/loose-*.pack >loose-packs &&
+	test_line_count = 1 loose-packs &&
+
+	# The second run deletes loose objects
+	# but does not create a pack-file.
+	git maintenance run --task=loose-objects &&
+	ls .git/objects >obj-dir-after &&
+	cat >expect <<-\EOF &&
+	info
+	pack
+	EOF
+	test_cmp expect obj-dir-after &&
+	ls .git/objects/pack/*.pack >packs-after &&
+	test_cmp packs-between packs-after
+'
+
+test_expect_success 'maintenance.loose-objects.auto' '
+	git repack -adk &&
+	GIT_TRACE2_EVENT="$(pwd)/trace-lo1.txt" \
+		git -c maintenance.loose-objects.auto=1 maintenance \
+		run --auto --task=loose-objects 2>/dev/null &&
+	test_subcommand ! git prune-packed --quiet <trace-lo1.txt &&
+	test_write_lines data-A | git hash-object -t blob --stdin -w &&
+	GIT_TRACE2_EVENT="$(pwd)/trace-loA" \
+		git -c maintenance.loose-objects.auto=2 \
+		maintenance run --auto --task=loose-objects 2>/dev/null &&
+	test_subcommand ! git prune-packed --quiet <trace-loA &&
+	test_write_lines data-B | git hash-object -t blob --stdin -w &&
+	GIT_TRACE2_EVENT="$(pwd)/trace-loB" \
+		git -c maintenance.loose-objects.auto=2 \
+		maintenance run --auto --task=loose-objects 2>/dev/null &&
+	test_subcommand git prune-packed --quiet <trace-loB &&
+	GIT_TRACE2_EVENT="$(pwd)/trace-loC" \
+		git -c maintenance.loose-objects.auto=2 \
+		maintenance run --auto --task=loose-objects 2>/dev/null &&
+	test_subcommand git prune-packed --quiet <trace-loC
+'
+
+test_expect_success 'incremental-repack task' '
+	packDir=.git/objects/pack &&
+	for i in $(test_seq 1 5)
+	do
+		test_commit $i || return 1
+	done &&
+
+	# Create three disjoint pack-files with size BIG, small, small.
+	echo HEAD~2 | git pack-objects --revs $packDir/test-1 &&
+	test_tick &&
+	git pack-objects --revs $packDir/test-2 <<-\EOF &&
+	HEAD~1
+	^HEAD~2
+	EOF
+	test_tick &&
+	git pack-objects --revs $packDir/test-3 <<-\EOF &&
+	HEAD
+	^HEAD~1
+	EOF
+	rm -f $packDir/pack-* &&
+	rm -f $packDir/loose-* &&
+	ls $packDir/*.pack >packs-before &&
+	test_line_count = 3 packs-before &&
+
+	# the job repacks the two into a new pack, but does not
+	# delete the old ones.
+	git maintenance run --task=incremental-repack &&
+	ls $packDir/*.pack >packs-between &&
+	test_line_count = 4 packs-between &&
+
+	# the job deletes the two old packs, and does not write
+	# a new one because the batch size is not high enough to
+	# pack the largest pack-file.
+	git maintenance run --task=incremental-repack &&
+	ls .git/objects/pack/*.pack >packs-after &&
+	test_line_count = 2 packs-after
+'
+
+test_expect_success EXPENSIVE 'incremental-repack 2g limit' '
+	for i in $(test_seq 1 5)
+	do
+		test-tool genrandom foo$i $((512 * 1024 * 1024 + 1)) >>big ||
+		return 1
+	done &&
+	git add big &&
+	git commit -m "Add big file (1)" &&
+
+	# ensure any possible loose objects are in a pack-file
+	git maintenance run --task=loose-objects &&
+
+	rm big &&
+	for i in $(test_seq 6 10)
+	do
+		test-tool genrandom foo$i $((512 * 1024 * 1024 + 1)) >>big ||
+		return 1
+	done &&
+	git add big &&
+	git commit -m "Add big file (2)" &&
+
+	# ensure any possible loose objects are in a pack-file
+	git maintenance run --task=loose-objects &&
+
+	# Now run the incremental-repack task and check the batch-size
+	GIT_TRACE2_EVENT="$(pwd)/run-2g.txt" git maintenance run \
+		--task=incremental-repack 2>/dev/null &&
+	test_subcommand git multi-pack-index repack \
+		 --no-progress --batch-size=2147483647 <run-2g.txt
+'
+
+test_expect_success 'maintenance.incremental-repack.auto' '
+	git repack -adk &&
+	git config core.multiPackIndex true &&
+	git multi-pack-index write &&
+	GIT_TRACE2_EVENT="$(pwd)/midx-init.txt" git \
+		-c maintenance.incremental-repack.auto=1 \
+		maintenance run --auto --task=incremental-repack 2>/dev/null &&
+	test_subcommand ! git multi-pack-index write --no-progress <midx-init.txt &&
+	test_commit A &&
+	git pack-objects --revs .git/objects/pack/pack <<-\EOF &&
+	HEAD
+	^HEAD~1
+	EOF
+	GIT_TRACE2_EVENT=$(pwd)/trace-A git \
+		-c maintenance.incremental-repack.auto=2 \
+		maintenance run --auto --task=incremental-repack 2>/dev/null &&
+	test_subcommand ! git multi-pack-index write --no-progress <trace-A &&
+	test_commit B &&
+	git pack-objects --revs .git/objects/pack/pack <<-\EOF &&
+	HEAD
+	^HEAD~1
+	EOF
+	GIT_TRACE2_EVENT=$(pwd)/trace-B git \
+		-c maintenance.incremental-repack.auto=2 \
+		maintenance run --auto --task=incremental-repack 2>/dev/null &&
+	test_subcommand git multi-pack-index write --no-progress <trace-B
+'
+
+test_expect_success '--auto and --schedule incompatible' '
+	test_must_fail git maintenance run --auto --schedule=daily 2>err &&
+	test_i18ngrep "at most one" err
+'
+
+test_expect_success 'invalid --schedule value' '
+	test_must_fail git maintenance run --schedule=annually 2>err &&
+	test_i18ngrep "unrecognized --schedule" err
+'
+
+test_expect_success '--schedule inheritance weekly -> daily -> hourly' '
+	git config maintenance.loose-objects.enabled true &&
+	git config maintenance.loose-objects.schedule hourly &&
+	git config maintenance.commit-graph.enabled true &&
+	git config maintenance.commit-graph.schedule daily &&
+	git config maintenance.incremental-repack.enabled true &&
+	git config maintenance.incremental-repack.schedule weekly &&
+
+	GIT_TRACE2_EVENT="$(pwd)/hourly.txt" \
+		git maintenance run --schedule=hourly 2>/dev/null &&
+	test_subcommand git prune-packed --quiet <hourly.txt &&
+	test_subcommand ! git commit-graph write --split --reachable \
+		--no-progress <hourly.txt &&
+	test_subcommand ! git multi-pack-index write --no-progress <hourly.txt &&
+
+	GIT_TRACE2_EVENT="$(pwd)/daily.txt" \
+		git maintenance run --schedule=daily 2>/dev/null &&
+	test_subcommand git prune-packed --quiet <daily.txt &&
+	test_subcommand git commit-graph write --split --reachable \
+		--no-progress <daily.txt &&
+	test_subcommand ! git multi-pack-index write --no-progress <daily.txt &&
+
+	GIT_TRACE2_EVENT="$(pwd)/weekly.txt" \
+		git maintenance run --schedule=weekly 2>/dev/null &&
+	test_subcommand git prune-packed --quiet <weekly.txt &&
+	test_subcommand git commit-graph write --split --reachable \
+		--no-progress <weekly.txt &&
+	test_subcommand git multi-pack-index write --no-progress <weekly.txt
+'
+
+test_expect_success 'register and unregister' '
+	test_when_finished git config --global --unset-all maintenance.repo &&
+	git config --global --add maintenance.repo /existing1 &&
+	git config --global --add maintenance.repo /existing2 &&
+	git config --global --get-all maintenance.repo >before &&
+
+	git maintenance register &&
+	test_cmp_config false maintenance.auto &&
+	git config --global --get-all maintenance.repo >between &&
+	cp before expect &&
+	pwd >>expect &&
+	test_cmp expect between &&
+
+	git maintenance unregister &&
+	git config --global --get-all maintenance.repo >actual &&
+	test_cmp before actual
+'
+
+test_expect_success 'start from empty cron table' '
+	GIT_TEST_CRONTAB="test-tool crontab cron.txt" git maintenance start &&
+
+	# start registers the repo
+	git config --get --global maintenance.repo "$(pwd)" &&
+
+	grep "for-each-repo --config=maintenance.repo maintenance run --schedule=daily" cron.txt &&
+	grep "for-each-repo --config=maintenance.repo maintenance run --schedule=hourly" cron.txt &&
+	grep "for-each-repo --config=maintenance.repo maintenance run --schedule=weekly" cron.txt
+'
+
+test_expect_success 'stop from existing schedule' '
+	GIT_TEST_CRONTAB="test-tool crontab cron.txt" git maintenance stop &&
+
+	# stop does not unregister the repo
+	git config --get --global maintenance.repo "$(pwd)" &&
+
+	# Operation is idempotent
+	GIT_TEST_CRONTAB="test-tool crontab cron.txt" git maintenance stop &&
+	test_must_be_empty cron.txt
+'
+
+test_expect_success 'start preserves existing schedule' '
+	echo "Important information!" >cron.txt &&
+	GIT_TEST_CRONTAB="test-tool crontab cron.txt" git maintenance start &&
+	grep "Important information!" cron.txt
+'
+
 test_done

t/test-lib.sh

@@ -1729,3 +1729,9 @@ test_lazy_prereq SHA1 '
 test_lazy_prereq REBASE_P '
 	test -z "$GIT_TEST_SKIP_REBASE_P"
 '
+
+# Ensure that no test accidentally triggers a Git command
+# that runs 'crontab', affecting a user's cron schedule.
+# Tests that verify the cron integration must set this locally
+# to avoid errors.
+GIT_TEST_CRONTAB="exit 1"