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core: remove JoinControllers= configuration setting 

This removes the ability to configure which cgroup controllers to mount
together. Instead, we'll now hardcode that "cpu" and "cpuacct" are
mounted together as well as "net_cls" and "net_prio".

The concept of mounting controllers together has no future as it does
not exist to cgroupsv2. Moreover, the current logic is systematically
broken, as revealed by the discussions in #10507. Also, we surveyed Red
Hat customers and couldn't find a single user of the concept (which
isn't particularly surprising, as it is broken...)

This reduced the (already way too complex) cgroup handling for us, since
we now know whenever we make a change to a cgroup for one controller to
which other controllers it applies.
This commit is contained in:
Lennart Poettering 2018-11-15 21:07:43 +01:00
parent 8d33dca2ff
commit 143fadf369
9 changed files with 80 additions and 255 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
man/systemd-system.conf.xml
View File

@ -106,29 +106,6 @@
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>JoinControllers=cpu,cpuacct net_cls,netprio</varname></term>
<listitem><para>Configures controllers that shall be mounted
in a single hierarchy. By default, systemd will mount all
controllers which are enabled in the kernel in individual
hierarchies, with the exception of those listed in this
setting. Takes a space-separated list of comma-separated
controller names, in order to allow multiple joined
hierarchies. Defaults to 'cpu,cpuacct'. Pass an empty string
to ensure that systemd mounts all controllers in separate
hierarchies.</para>
<para>Note that this option is only applied once, at very
early boot. If you use an initial RAM disk (initrd) that uses
systemd, it might hence be necessary to rebuild the initrd if
this option is changed, and make sure the new configuration
file is included in it. Otherwise, the initrd might mount the
controller hierarchies in a different configuration than
intended, and the main system cannot remount them
anymore.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>RuntimeWatchdogSec=</varname></term>
<term><varname>ShutdownWatchdogSec=</varname></term>

6
src/core/main.c
View File

@ -100,7 +100,6 @@ static ShowStatus arg_show_status = _SHOW_STATUS_INVALID;
static bool arg_switched_root = false;
static PagerFlags arg_pager_flags = 0;
static bool arg_service_watchdogs = true;
static char ***arg_join_controllers = NULL;
static ExecOutput arg_default_std_output = EXEC_OUTPUT_JOURNAL;
static ExecOutput arg_default_std_error = EXEC_OUTPUT_INHERIT;
static usec_t arg_default_restart_usec = DEFAULT_RESTART_USEC;
@ -667,7 +666,7 @@ static int parse_config_file(void) {
{ "Manager", "CrashReboot", config_parse_bool, 0, &arg_crash_reboot },
{ "Manager", "ShowStatus", config_parse_show_status, 0, &arg_show_status },
{ "Manager", "CPUAffinity", config_parse_cpu_affinity2, 0, NULL },
{ "Manager", "JoinControllers", config_parse_join_controllers, 0, &arg_join_controllers },
{ "Manager", "JoinControllers", config_parse_warn_compat, DISABLED_CONFIGURATION, NULL },
{ "Manager", "RuntimeWatchdogSec", config_parse_sec, 0, &arg_runtime_watchdog },
{ "Manager", "ShutdownWatchdogSec", config_parse_sec, 0, &arg_shutdown_watchdog },
{ "Manager", "WatchdogDevice", config_parse_path, 0, &arg_watchdog_device },
@ -1956,7 +1955,7 @@ static int initialize_runtime(
install_crash_handler();
if (!skip_setup) {
r = mount_cgroup_controllers(arg_join_controllers);
r = mount_cgroup_controllers();
if (r < 0) {
*ret_error_message = "Failed to mount cgroup hierarchies";
return r;
@ -2081,7 +2080,6 @@ static void free_arguments(void) {
arg_default_unit = mfree(arg_default_unit);
arg_confirm_spawn = mfree(arg_confirm_spawn);
arg_join_controllers = strv_free_free(arg_join_controllers);
arg_default_environment = strv_free(arg_default_environment);
arg_syscall_archs = set_free(arg_syscall_archs);
}

146
src/core/mount-setup.c
View File

@ -229,76 +229,105 @@ int mount_setup_early(void) {
return mount_points_setup(N_EARLY_MOUNT, false);
}
int mount_cgroup_controllers(char ***join_controllers) {
static const char *join_with(const char *controller) {
static const char* const pairs[] = {
"cpu", "cpuacct",
"net_cls", "net_prio",
NULL
};
const char *const *x, *const *y;
assert(controller);
/* This will lookup which controller to mount another controller with. Input is a controller name, and output
* is the other controller name. The function works both ways: you can input one and get the other, and input
* the other to get the one. */
STRV_FOREACH_PAIR(x, y, pairs) {
if (streq(controller, *x))
return *y;
if (streq(controller, *y))
return *x;
}
return NULL;
}
static int symlink_controller(const char *target, const char *alias) {
const char *a;
int r;
assert(target);
assert(alias);
a = strjoina("/sys/fs/cgroup/", alias);
r = symlink_idempotent(target, a, false);
if (r < 0)
return log_error_errno(r, "Failed to create symlink %s: %m", a);
#ifdef SMACK_RUN_LABEL
const char *p;
p = strjoina("/sys/fs/cgroup/", target);
r = mac_smack_copy(a, p);
if (r < 0 && r != -EOPNOTSUPP)
return log_error_errno(r, "Failed to copy smack label from %s to %s: %m", p, a);
#endif
return 0;
}
int mount_cgroup_controllers(void) {
_cleanup_set_free_free_ Set *controllers = NULL;
bool has_argument = !!join_controllers;
int r;
if (!cg_is_legacy_wanted())
return 0;
/* Mount all available cgroup controllers that are built into the kernel. */
if (!has_argument)
/* The defaults:
* mount "cpu" + "cpuacct" together, and "net_cls" + "net_prio".
*
* We'd like to add "cpuset" to the mix, but "cpuset" doesn't really
* work for groups with no initialized attributes.
*/
join_controllers = (char**[]) {
STRV_MAKE("cpu", "cpuacct"),
STRV_MAKE("net_cls", "net_prio"),
NULL,
};
r = cg_kernel_controllers(&controllers);
if (r < 0)
return log_error_errno(r, "Failed to enumerate cgroup controllers: %m");
for (;;) {
_cleanup_free_ char *options = NULL, *controller = NULL, *where = NULL;
const char *other_controller;
MountPoint p = {
.what = "cgroup",
.type = "cgroup",
.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
.mode = MNT_IN_CONTAINER,
};
char ***k = NULL;
controller = set_steal_first(controllers);
if (!controller)
break;
for (k = join_controllers; *k; k++)
if (strv_find(*k, controller))
break;
/* Check if we shall mount this together with another controller */
other_controller = join_with(controller);
if (other_controller) {
_cleanup_free_ char *c = NULL;
if (*k) {
char **i, **j;
/* Check if the other controller is actually available in the kernel too */
c = set_remove(controllers, other_controller);
if (c) {
for (i = *k, j = *k; *i; i++) {
if (!streq(*i, controller)) {
_cleanup_free_ char *t;
t = set_remove(controllers, *i);
if (!t) {
if (has_argument)
free(*i);
continue;
}
}
*(j++) = *i;
/* Join the two controllers into one string, and maintain a stable ordering */
if (strcmp(controller, other_controller) < 0)
options = strjoin(controller, ",", other_controller);
else
options = strjoin(other_controller, ",", controller);
if (!options)
return log_oom();
}
}
*j = NULL;
options = strv_join(*k, ",");
if (!options)
return log_oom();
} else
/* The simple case, where there's only one controller to mount together */
if (!options)
options = TAKE_PTR(controller);
where = strappend("/sys/fs/cgroup/", options);
@ -312,35 +341,14 @@ int mount_cgroup_controllers(char ***join_controllers) {
if (r < 0)
return r;
if (r > 0 && *k) {
char **i;
for (i = *k; *i; i++) {
_cleanup_free_ char *t = NULL;
t = strappend("/sys/fs/cgroup/", *i);
if (!t)
return log_oom();
r = symlink(options, t);
if (r >= 0) {
#ifdef SMACK_RUN_LABEL
_cleanup_free_ char *src;
src = strappend("/sys/fs/cgroup/", options);
if (!src)
return log_oom();
r = mac_smack_copy(t, src);
if (r < 0 && r != -EOPNOTSUPP)
return log_error_errno(r, "Failed to copy smack label from %s to %s: %m", src, t);
#endif
} else if (errno != EEXIST)
return log_error_errno(errno, "Failed to create symlink %s: %m", t);
}
}
/* Create symlinks from the individual controller names, in case we have a joined mount */
if (controller)
(void) symlink_controller(options, controller);
if (other_controller)
(void) symlink_controller(options, other_controller);
}
/* Now that we mounted everything, let's make the tmpfs the
* cgroup file systems are mounted into read-only. */
/* Now that we mounted everything, let's make the tmpfs the cgroup file systems are mounted into read-only. */
(void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755");
return 0;

2
src/core/mount-setup.h
View File

@ -6,7 +6,7 @@
int mount_setup_early(void);
int mount_setup(bool loaded_policy);
int mount_cgroup_controllers(char ***join_controllers);
int mount_cgroup_controllers(void);
bool mount_point_is_api(const char *path);
bool mount_point_ignore(const char *path);

1
src/core/system.conf.in
View File

@ -23,7 +23,6 @@
#CrashReboot=no
#CtrlAltDelBurstAction=reboot-force
#CPUAffinity=1 2
#JoinControllers=cpu,cpuacct net_cls,net_prio
#RuntimeWatchdogSec=0
#ShutdownWatchdogSec=10min
#WatchdogDevice=

115
src/shared/conf-parser.c
View File

@ -1013,121 +1013,6 @@ int config_parse_ip_port(
return 0;
}
int config_parse_join_controllers(
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) {
char ****ret = data;
const char *whole_rvalue = rvalue;
unsigned n = 0;
_cleanup_(strv_free_freep) char ***controllers = NULL;
assert(filename);
assert(lvalue);
assert(rvalue);
assert(ret);
for (;;) {
_cleanup_free_ char *word = NULL;
char **l;
int r;
r = extract_first_word(&rvalue, &word, NULL, EXTRACT_QUOTES);
if (r < 0) {
log_syntax(unit, LOG_ERR, filename, line, r, "Invalid value for %s: %s", lvalue, whole_rvalue);
return r;
}
if (r == 0)
break;
l = strv_split(word, ",");
if (!l)
return log_oom();
strv_uniq(l);
if (strv_length(l) <= 1) {
strv_free(l);
continue;
}
if (!controllers) {
controllers = new(char**, 2);
if (!controllers) {
strv_free(l);
return log_oom();
}
controllers[0] = l;
controllers[1] = NULL;
n = 1;
} else {
char ***a;
char ***t;
t = new0(char**, n+2);
if (!t) {
strv_free(l);
return log_oom();
}
n = 0;
for (a = controllers; *a; a++)
if (strv_overlap(*a, l)) {
if (strv_extend_strv(&l, *a, false) < 0) {
strv_free(l);
strv_free_free(t);
return log_oom();
}
} else {
char **c;
c = strv_copy(*a);
if (!c) {
strv_free(l);
strv_free_free(t);
return log_oom();
}
t[n++] = c;
}
t[n++] = strv_uniq(l);
strv_free_free(controllers);
controllers = t;
}
}
if (!isempty(rvalue))
log_syntax(unit, LOG_ERR, filename, line, 0, "Trailing garbage, ignoring.");
/* As a special case, return a single empty strv, to override the default */
if (!controllers) {
controllers = new(char**, 2);
if (!controllers)
return log_oom();
controllers[0] = strv_new(NULL);
if (!controllers[0])
return log_oom();
controllers[1] = NULL;
}
strv_free_free(*ret);
*ret = TAKE_PTR(controllers);
return 0;
}
int config_parse_mtu(
const char *unit,
const char *filename,

1
src/shared/conf-parser.h
View File

@ -137,7 +137,6 @@ CONFIG_PARSER_PROTOTYPE(config_parse_personality);
CONFIG_PARSER_PROTOTYPE(config_parse_permille);
CONFIG_PARSER_PROTOTYPE(config_parse_ifname);
CONFIG_PARSER_PROTOTYPE(config_parse_ip_port);
CONFIG_PARSER_PROTOTYPE(config_parse_join_controllers);
CONFIG_PARSER_PROTOTYPE(config_parse_mtu);
CONFIG_PARSER_PROTOTYPE(config_parse_rlimit);

40
src/test/test-conf-parser.c
View File

@ -210,45 +210,6 @@ static void test_config_parse_iec_uint64(void) {
assert_se(config_parse_iec_uint64(NULL, "/this/file", 11, "Section", 22, "Size", 0, "4.5M", &offset, NULL) == 0);
}
static void test_config_parse_join_controllers(void) {
int r;
_cleanup_(strv_free_freep) char ***c = NULL;
char ***c2;
/* Test normal operation */
r = config_parse_join_controllers(NULL, "example.conf", 11, "Section", 10, "JoinControllers", 0, "cpu,cpuacct net_cls,netprio", &c, NULL);
assert_se(r == 0);
assert_se(c);
assert_se(strv_length(c[0]) == 2);
assert_se(strv_equal(c[0], STRV_MAKE("cpu", "cpuacct")));
assert_se(strv_length(c[1]) == 2);
assert_se(strv_equal(c[1], STRV_MAKE("net_cls", "netprio")));
assert_se(c[2] == NULL);
/* Test special case of no mounted controllers */
r = config_parse_join_controllers(NULL, "example.conf", 12, "Section", 10, "JoinControllers", 0, "", &c, NULL);
assert_se(r == 0);
assert_se(c);
assert_se(strv_equal(c[0], STRV_MAKE_EMPTY));
assert_se(c[1] == NULL);
/* Test merging of overlapping lists */
r = config_parse_join_controllers(NULL, "example.conf", 13, "Section", 10, "JoinControllers", 0, "a,b b,c", &c, NULL);
assert_se(r == 0);
assert_se(c);
assert_se(strv_length(c[0]) == 3);
assert_se(strv_contains(c[0], "a"));
assert_se(strv_contains(c[0], "b"));
assert_se(strv_contains(c[0], "c"));
assert_se(c[1] == NULL);
/* Test ignoring of bad lines */
c2 = c;
r = config_parse_join_controllers(NULL, "example.conf", 14, "Section", 10, "JoinControllers", 0, "a,\"b ", &c, NULL);
assert_se(r < 0);
assert_se(c == c2);
}
#define x10(x) x x x x x x x x x x
#define x100(x) x10(x10(x))
#define x1000(x) x10(x100(x))
@ -407,7 +368,6 @@ int main(int argc, char **argv) {
test_config_parse_sec();
test_config_parse_nsec();
test_config_parse_iec_uint64();
test_config_parse_join_controllers();
for (i = 0; i < ELEMENTSOF(config_file); i++)
test_config_parse(i, config_file[i]);

1
test/fuzz/fuzz-unit-file/directives.service
View File

@ -690,7 +690,6 @@ HibernateMode=
HibernateState=
HybridSleepMode=
HybridSleepState=
JoinControllers=
LogColor=
LogLevel=
LogLocation=