diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml index d6feaa1817..72c66028f8 100644 --- a/man/systemd.unit.xml +++ b/man/systemd.unit.xml @@ -213,7 +213,6 @@ socket-based activation which make dependencies implicit, resulting in a both simpler and more flexible system. - Optionally, units may be instantiated from a template file at runtime. This allows creation of multiple units from a single configuration file. If @@ -417,6 +416,45 @@ + + Unit Garbage Collection + + The system and service manager loads a unit's configuration automatically when a unit is referenced for the + first time. It will automatically unload the unit configuration and state again when the unit is not needed anymore + ("garbage collection"). A unit may be referenced through a number of different mechanisms: + + + Another loaded unit references it with a dependency such as After=, + Wants=, … + + The unit is currently starting, running, reloading or stopping. + + The unit is currently in the failed state. (But see below.) + + A job for the unit is pending. + + The unit is pinned by an active IPC client program. + + The unit is a special "perpetual" unit that is always active and loaded. Examples for perpetual + units are the root mount unit -.mount or the scope unit init.scope that + the service manager itself lives in. + + The unit has running processes associated with it. + + + The garbage collection logic may be altered with the CollectMode= option, which allows + configuration whether automatic unloading of units that are in failed state is permissible, + see below. + + Note that when a unit's configuration and state is unloaded, all execution results, such as exit codes, exit + signals, resource consumption and other statistics are lost, except for what is stored in the log subsystem. + + Use systemctl daemon-reload or an equivalent command to reload unit configuration while + the unit is already loaded. In this case all configuration settings are flushed out and replaced with the new + configuration (which however might not be in effect immediately), however all runtime state is + saved/restored. + + [Unit] Section Options @@ -747,6 +785,23 @@ ones. + + CollectMode= + + Tweaks the "garbage collection" algorithm for this unit. Takes one of + or . If set to the unit will be unloaded if it is + in the inactive state and is not referenced by clients, jobs or other units — however it + is not unloaded if it is in the failed state. In mode, failed + units are not unloaded until the user invoked systemctl reset-failed on them to reset the + failed state, or an equivalent command. This behaviour is altered if this option is set to + : in this case the unit is unloaded even if the unit is in a + failed state, and thus an explicitly resetting of the failed state is + not necessary. Note that if this mode is used unit results (such as exit codes, exit signals, consumed + resources, …) are flushed out immediately after the unit completed, except for what is stored in the logging + subsystem. Defaults to . + + + JobTimeoutSec= JobRunningTimeoutSec= diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c index 32fcb5ef1c..561cf453f6 100644 --- a/src/core/dbus-unit.c +++ b/src/core/dbus-unit.c @@ -37,6 +37,7 @@ #include "strv.h" #include "user-util.h" +static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_collect_mode, collect_mode, CollectMode); static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_load_state, unit_load_state, UnitLoadState); static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_job_mode, job_mode, JobMode); static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_emergency_action, emergency_action, EmergencyAction); @@ -798,6 +799,7 @@ const sd_bus_vtable bus_unit_vtable[] = { SD_BUS_PROPERTY("StartLimitAction", "s", property_get_emergency_action, offsetof(Unit, start_limit_action), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("RebootArgument", "s", NULL, offsetof(Unit, reboot_arg), SD_BUS_VTABLE_PROPERTY_CONST), SD_BUS_PROPERTY("InvocationID", "ay", bus_property_get_id128, offsetof(Unit, invocation_id), 0), + SD_BUS_PROPERTY("CollectMode", "s", property_get_collect_mode, offsetof(Unit, collect_mode), 0), SD_BUS_METHOD("Start", "s", "o", method_start, SD_BUS_VTABLE_UNPRIVILEGED), SD_BUS_METHOD("Stop", "s", "o", method_stop, SD_BUS_VTABLE_UNPRIVILEGED), @@ -1354,6 +1356,25 @@ static int bus_unit_set_transient_property( return 1; + } else if (streq(name, "CollectMode")) { + const char *s; + CollectMode m; + + r = sd_bus_message_read(message, "s", &s); + if (r < 0) + return r; + + m = collect_mode_from_string(s); + if (m < 0) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown garbage collection mode: %s", s); + + if (mode != UNIT_CHECK) { + u->collect_mode = m; + unit_write_drop_in_format(u, mode, name, "[Unit]\nCollectMode=%s", collect_mode_to_string(m)); + } + + return 1; + } else if (streq(name, "Slice")) { Unit *slice; const char *s; diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4 index 5b73f9aa9b..ffc3e20359 100644 --- a/src/core/load-fragment-gperf.gperf.m4 +++ b/src/core/load-fragment-gperf.gperf.m4 @@ -264,6 +264,7 @@ Unit.AssertACPower, config_parse_unit_condition_string, CONDITION_A Unit.AssertUser, config_parse_unit_condition_string, CONDITION_USER, offsetof(Unit, asserts) Unit.AssertGroup, config_parse_unit_condition_string, CONDITION_GROUP, offsetof(Unit, asserts) Unit.AssertNull, config_parse_unit_condition_null, 0, offsetof(Unit, asserts) +Unit.CollectMode, config_parse_collect_mode, 0, offsetof(Unit, collect_mode) m4_dnl Service.PIDFile, config_parse_unit_path_printf, 0, offsetof(Service, pid_file) Service.ExecStartPre, config_parse_exec, SERVICE_EXEC_START_PRE, offsetof(Service, exec_command) diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c index 34fc04b65a..c1cf8379e8 100644 --- a/src/core/load-fragment.c +++ b/src/core/load-fragment.c @@ -103,6 +103,8 @@ int config_parse_warn_compat( return 0; } +DEFINE_CONFIG_PARSE_ENUM(config_parse_collect_mode, collect_mode, CollectMode, "Failed to parse garbage collection mode"); + int config_parse_unit_deps( const char *unit, const char *filename, diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h index b0a3ce2c67..fbf2de23eb 100644 --- a/src/core/load-fragment.h +++ b/src/core/load-fragment.h @@ -122,6 +122,7 @@ int config_parse_exec_keyring_mode(const char *unit, const char *filename, unsig int config_parse_job_timeout_sec(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); int config_parse_job_running_timeout_sec(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); int config_parse_log_extra_fields(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); +int config_parse_collect_mode(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata); /* gperf prototypes */ const struct ConfigPerfItem* load_fragment_gperf_lookup(const char *key, GPERF_LEN_TYPE length); diff --git a/src/core/unit.c b/src/core/unit.c index 5c8dc4347a..25cdc04506 100644 --- a/src/core/unit.c +++ b/src/core/unit.c @@ -56,6 +56,7 @@ #include "special.h" #include "stat-util.h" #include "stdio-util.h" +#include "string-table.h" #include "string-util.h" #include "strv.h" #include "umask-util.h" @@ -75,7 +76,7 @@ const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX] = { [UNIT_TIMER] = &timer_vtable, [UNIT_PATH] = &path_vtable, [UNIT_SLICE] = &slice_vtable, - [UNIT_SCOPE] = &scope_vtable + [UNIT_SCOPE] = &scope_vtable, }; static void maybe_warn_about_dependency(Unit *u, const char *other, UnitDependency dependency); @@ -331,8 +332,12 @@ int unit_set_description(Unit *u, const char *description) { bool unit_check_gc(Unit *u) { UnitActiveState state; + assert(u); + /* Checks whether the unit is ready to be unloaded for garbage collection. Returns true, when the unit shall + * stay around, false if there's no reason to keep it loaded. */ + if (u->job) return true; @@ -346,10 +351,6 @@ bool unit_check_gc(Unit *u) { UNIT_VTABLE(u)->release_resources) UNIT_VTABLE(u)->release_resources(u); - /* But we keep the unit object around for longer when it is referenced or configured to not be gc'ed */ - if (state != UNIT_INACTIVE) - return true; - if (u->perpetual) return true; @@ -359,6 +360,25 @@ bool unit_check_gc(Unit *u) { if (sd_bus_track_count(u->bus_track) > 0) return true; + /* But we keep the unit object around for longer when it is referenced or configured to not be gc'ed */ + switch (u->collect_mode) { + + case COLLECT_INACTIVE: + if (state != UNIT_INACTIVE) + return true; + + break; + + case COLLECT_INACTIVE_OR_FAILED: + if (!IN_SET(state, UNIT_INACTIVE, UNIT_FAILED)) + return true; + + break; + + default: + assert_not_reached("Unknown garbage collection mode"); + } + if (UNIT_VTABLE(u)->check_gc) if (UNIT_VTABLE(u)->check_gc(u)) return true; @@ -1083,6 +1103,7 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) { "%s\tNeed Daemon Reload: %s\n" "%s\tTransient: %s\n" "%s\tPerpetual: %s\n" + "%s\tGarbage Collection Mode: %s\n" "%s\tSlice: %s\n" "%s\tCGroup: %s\n" "%s\tCGroup realized: %s\n", @@ -1100,6 +1121,7 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) { prefix, yes_no(unit_need_daemon_reload(u)), prefix, yes_no(u->transient), prefix, yes_no(u->perpetual), + prefix, collect_mode_to_string(u->collect_mode), prefix, strna(unit_slice_name(u)), prefix, strna(u->cgroup_path), prefix, yes_no(u->cgroup_realized)); @@ -5121,3 +5143,10 @@ void unit_unlink_state_files(Unit *u) { u->exported_log_extra_fields = false; } } + +static const char* const collect_mode_table[_COLLECT_MODE_MAX] = { + [COLLECT_INACTIVE] = "inactive", + [COLLECT_INACTIVE_OR_FAILED] = "inactive-or-failed", +}; + +DEFINE_STRING_TABLE_LOOKUP(collect_mode, CollectMode); diff --git a/src/core/unit.h b/src/core/unit.h index b0df341a03..03dd88dcca 100644 --- a/src/core/unit.h +++ b/src/core/unit.h @@ -45,6 +45,13 @@ typedef enum KillOperation { _KILL_OPERATION_INVALID = -1 } KillOperation; +typedef enum CollectMode { + COLLECT_INACTIVE, + COLLECT_INACTIVE_OR_FAILED, + _COLLECT_MODE_MAX, + _COLLECT_MODE_INVALID = -1, +} CollectMode; + static inline bool UNIT_IS_ACTIVE_OR_RELOADING(UnitActiveState t) { return IN_SET(t, UNIT_ACTIVE, UNIT_RELOADING); } @@ -282,6 +289,9 @@ struct Unit { /* How to start OnFailure units */ JobMode on_failure_job_mode; + /* Tweaking the GC logic */ + CollectMode collect_mode; + /* The current invocation ID */ sd_id128_t invocation_id; char invocation_id_string[SD_ID128_STRING_MAX]; /* useful when logging */ @@ -773,3 +783,6 @@ void unit_unlink_state_files(Unit *u); #define LOG_UNIT_MESSAGE(unit, fmt, ...) "MESSAGE=%s: " fmt, (unit)->id, ##__VA_ARGS__ #define LOG_UNIT_ID(unit) (unit)->manager->unit_log_format_string, (unit)->id #define LOG_UNIT_INVOCATION_ID(unit) (unit)->manager->invocation_log_format_string, (unit)->invocation_id_string + +const char* collect_mode_to_string(CollectMode m) _const_; +CollectMode collect_mode_from_string(const char *s) _pure_; diff --git a/src/shared/bus-unit-util.c b/src/shared/bus-unit-util.c index e24c0d4e1c..2b2480c2e1 100644 --- a/src/shared/bus-unit-util.c +++ b/src/shared/bus-unit-util.c @@ -371,7 +371,7 @@ int bus_append_unit_property_assignment(sd_bus_message *m, const char *assignmen "RootDirectory", "SyslogIdentifier", "ProtectSystem", "ProtectHome", "SELinuxContext", "Restart", "RootImage", "NotifyAccess", "RuntimeDirectoryPreserve", "Personality", - "KeyringMode")) + "KeyringMode", "CollectMode")) r = sd_bus_message_append(m, "v", "s", eq); else if (STR_IN_SET(field, "AppArmorProfile", "SmackProcessLabel")) {