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core: introduce support for cgroup freezer

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With cgroup v2 the cgroup freezer is implemented as a cgroup
attribute called cgroup.freeze. cgroup can be frozen by writing "1"
to the file and kernel will send us a notification through
"cgroup.events" after the operation is finished and processes in the
cgroup entered quiescent state, i.e. they are not scheduled to
run. Writing "0" to the attribute file does the inverse and process
execution is resumed.

This commit exposes above low-level functionality through systemd's DBus
API. Each unit type must provide specialized implementation for these
methods, otherwise, we return an error. So far only service, scope, and
slice unit types provide the support. It is possible to check if a
given unit has the support using CanFreeze() DBus property.

Note that DBus API has a synchronous behavior and we dispatch the reply
to freeze/thaw requests only after the kernel has notified us that
requested operation was completed.
This commit is contained in:
Michal Sekletár
2020-04-30 19:02:51 +02:00
parent 25a1f04c68
commit d9e45bc3ab
19 changed files with 566 additions and 14 deletions
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src/systemctl/systemctl.c
+30 -9
View File
@@ -3834,11 +3834,12 @@ static int kill_unit(int argc, char *argv[], void *userdata) {
return r;
}
static int clean_unit(int argc, char *argv[], void *userdata) {
static int clean_or_freeze_unit(int argc, char *argv[], void *userdata) {
_cleanup_(bus_wait_for_units_freep) BusWaitForUnits *w = NULL;
_cleanup_strv_free_ char **names = NULL;
int r, ret = EXIT_SUCCESS;
char **name;
const char *method;
sd_bus *bus;
r = acquire_bus(BUS_FULL, &bus);
@@ -3863,6 +3864,13 @@ static int clean_unit(int argc, char *argv[], void *userdata) {
return log_error_errno(r, "Failed to allocate unit waiter: %m");
}
if (streq(argv[0], "clean"))
method = "CleanUnit";
else if (streq(argv[0], "freeze"))
method = "FreezeUnit";
else if (streq(argv[0], "thaw"))
method = "ThawUnit";
STRV_FOREACH(name, names) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
@@ -3892,7 +3900,7 @@ static int clean_unit(int argc, char *argv[], void *userdata) {
"org.freedesktop.systemd1",
"/org/freedesktop/systemd1",
"org.freedesktop.systemd1.Manager",
"CleanUnit");
method);
if (r < 0)
return bus_log_create_error(r);
@@ -3900,13 +3908,15 @@ static int clean_unit(int argc, char *argv[], void *userdata) {
if (r < 0)
return bus_log_create_error(r);
r = sd_bus_message_append_strv(m, arg_clean_what);
if (r < 0)
return bus_log_create_error(r);
if (streq(method, "CleanUnit")) {
r = sd_bus_message_append_strv(m, arg_clean_what);
if (r < 0)
return bus_log_create_error(r);
}
r = sd_bus_call(bus, m, 0, &error, NULL);
if (r < 0) {
log_error_errno(r, "Failed to clean unit %s: %s", *name, bus_error_message(&error, r));
log_error_errno(r, "Failed to %s unit %s: %s", argv[0], *name, bus_error_message(&error, r));
if (ret == EXIT_SUCCESS) {
ret = r;
continue;
@@ -4046,6 +4056,7 @@ typedef struct UnitStatusInfo {
const char *id;
const char *load_state;
const char *active_state;
const char *freezer_state;
const char *sub_state;
const char *unit_file_state;
const char *unit_file_preset;
@@ -4182,7 +4193,7 @@ static void print_status_info(
bool *ellipsized) {
char since1[FORMAT_TIMESTAMP_RELATIVE_MAX], since2[FORMAT_TIMESTAMP_MAX];
const char *s1, *s2, *active_on, *active_off, *on, *off, *ss;
const char *s1, *s2, *active_on, *active_off, *on, *off, *ss, *fs;
_cleanup_free_ char *formatted_path = NULL;
ExecStatusInfo *p;
usec_t timestamp;
@@ -4276,12 +4287,16 @@ static void print_status_info(
ss = streq_ptr(i->active_state, i->sub_state) ? NULL : i->sub_state;
if (ss)
printf(" Active: %s%s (%s)%s",
printf(" Active: %s%s (%s)%s",
active_on, strna(i->active_state), ss, active_off);
else
printf(" Active: %s%s%s",
active_on, strna(i->active_state), active_off);
fs = !isempty(i->freezer_state) && !streq(i->freezer_state, "running") ? i->freezer_state : NULL;
if (fs)
printf(" %s(%s)%s", ansi_highlight_yellow(), fs, active_off);
if (!isempty(i->result) && !streq(i->result, "success"))
printf(" (Result: %s)", i->result);
@@ -5539,12 +5554,14 @@ static int show_one(
static const struct bus_properties_map property_map[] = {
{ "LoadState", "s", NULL, offsetof(UnitStatusInfo, load_state) },
{ "ActiveState", "s", NULL, offsetof(UnitStatusInfo, active_state) },
{ "FreezerState", "s", NULL, offsetof(UnitStatusInfo, freezer_state) },
{ "Documentation", "as", NULL, offsetof(UnitStatusInfo, documentation) },
{}
}, status_map[] = {
{ "Id", "s", NULL, offsetof(UnitStatusInfo, id) },
{ "LoadState", "s", NULL, offsetof(UnitStatusInfo, load_state) },
{ "ActiveState", "s", NULL, offsetof(UnitStatusInfo, active_state) },
{ "FreezerState", "s", NULL, offsetof(UnitStatusInfo, freezer_state) },
{ "SubState", "s", NULL, offsetof(UnitStatusInfo, sub_state) },
{ "UnitFileState", "s", NULL, offsetof(UnitStatusInfo, unit_file_state) },
{ "UnitFilePreset", "s", NULL, offsetof(UnitStatusInfo, unit_file_preset) },
@@ -7887,6 +7904,8 @@ static int systemctl_help(void) {
" kill UNIT... Send signal to processes of a unit\n"
" clean UNIT... Clean runtime, cache, state, logs or\n"
" configuration of unit\n"
" freeze PATTERN... Freeze execution of unit processes\n"
" thaw PATTERN... Resume execution of a frozen unit\n"
" is-active PATTERN... Check whether units are active\n"
" is-failed PATTERN... Check whether units are failed\n"
" status [PATTERN...|PID...] Show runtime status of one or more units\n"
@@ -9160,7 +9179,9 @@ static int systemctl_main(int argc, char *argv[]) {
{ "condrestart", 2, VERB_ANY, VERB_ONLINE_ONLY, start_unit }, /* For compatibility with RH */
{ "isolate", 2, 2, VERB_ONLINE_ONLY, start_unit },
{ "kill", 2, VERB_ANY, VERB_ONLINE_ONLY, kill_unit },
{ "clean", 2, VERB_ANY, VERB_ONLINE_ONLY, clean_unit },
{ "clean", 2, VERB_ANY, VERB_ONLINE_ONLY, clean_or_freeze_unit },
{ "freeze", 2, VERB_ANY, VERB_ONLINE_ONLY, clean_or_freeze_unit },
{ "thaw", 2, VERB_ANY, VERB_ONLINE_ONLY, clean_or_freeze_unit },
{ "is-active", 2, VERB_ANY, VERB_ONLINE_ONLY, check_unit_active },
{ "check", 2, VERB_ANY, VERB_ONLINE_ONLY, check_unit_active }, /* deprecated alias of is-active */
{ "is-failed", 2, VERB_ANY, VERB_ONLINE_ONLY, check_unit_failed },