cgroup-util: helper to cg_get_attribute and convert to uint64_t

A common pattern in the codebase is reading a cgroup memory value
and converting it to a uint64_t. Let's make it a helper and refactor a
few places to use it so it's more concise.
This commit is contained in:
Anita Zhang 2020-03-07 17:14:35 -08:00
parent 1b43e24602
commit 613328c3e2
4 changed files with 34 additions and 60 deletions

View File

@ -1639,6 +1639,32 @@ int cg_get_attribute(const char *controller, const char *path, const char *attri
return read_one_line_file(p, ret);
}
int cg_get_attribute_as_uint64(const char *controller, const char *path, const char *attribute, uint64_t *ret) {
_cleanup_free_ char *value = NULL;
uint64_t v;
int r;
assert(ret);
r = cg_get_attribute(controller, path, attribute, &value);
if (r == -ENOENT)
return -ENODATA;
if (r < 0)
return r;
if (streq(value, "max")) {
*ret = CGROUP_LIMIT_MAX;
return 0;
}
r = safe_atou64(value, &v);
if (r < 0)
return r;
*ret = v;
return 0;
}
int cg_get_keyed_attribute(
const char *controller,
const char *path,

View File

@ -184,6 +184,8 @@ int cg_set_attribute(const char *controller, const char *path, const char *attri
int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret);
int cg_get_keyed_attribute(const char *controller, const char *path, const char *attribute, char **keys, char **values);
int cg_get_attribute_as_uint64(const char *controller, const char *path, const char *attribute, uint64_t *ret);
int cg_set_access(const char *controller, const char *path, uid_t uid, gid_t gid);
int cg_set_xattr(const char *controller, const char *path, const char *name, const void *value, size_t size, int flags);

View File

@ -120,16 +120,9 @@ uint64_t system_tasks_max(void) {
if (r < 0)
log_debug_errno(r, "Failed to determine cgroup root path, ignoring: %m");
else {
_cleanup_free_ char *value = NULL;
r = cg_get_attribute("pids", root, "pids.max", &value);
r = cg_get_attribute_as_uint64("pids", root, "pids.max", &b);
if (r < 0)
log_debug_errno(r, "Failed to read pids.max attribute of cgroup root, ignoring: %m");
else if (!streq(value, "max")) {
r = safe_atou64(value, &b);
if (r < 0)
log_debug_errno(r, "Failed to parse pids.max attribute of cgroup root, ignoring: %m");
}
}
return MIN3(TASKS_MAX,

View File

@ -215,31 +215,12 @@ void cgroup_context_done(CGroupContext *c) {
}
static int unit_get_kernel_memory_limit(Unit *u, const char *file, uint64_t *ret) {
_cleanup_free_ char *raw_kval = NULL;
uint64_t kval;
int r;
assert(u);
if (!u->cgroup_realized)
return -EOWNERDEAD;
r = cg_get_attribute("memory", u->cgroup_path, file, &raw_kval);
if (r < 0)
return r;
if (streq(raw_kval, "max")) {
*ret = CGROUP_LIMIT_MAX;
return 0;
}
r = safe_atou64(raw_kval, &kval);
if (r < 0)
return r;
*ret = kval;
return 0;
return cg_get_attribute_as_uint64("memory", u->cgroup_path, file, ret);
}
static int unit_compare_memory_limit(Unit *u, const char *property_name, uint64_t *ret_unit_value, uint64_t *ret_kernel_value) {
@ -3112,7 +3093,6 @@ int manager_notify_cgroup_empty(Manager *m, const char *cgroup) {
}
int unit_get_memory_current(Unit *u, uint64_t *ret) {
_cleanup_free_ char *v = NULL;
int r;
assert(u);
@ -3134,22 +3114,11 @@ int unit_get_memory_current(Unit *u, uint64_t *ret) {
r = cg_all_unified();
if (r < 0)
return r;
if (r > 0)
r = cg_get_attribute("memory", u->cgroup_path, "memory.current", &v);
else
r = cg_get_attribute("memory", u->cgroup_path, "memory.usage_in_bytes", &v);
if (r == -ENOENT)
return -ENODATA;
if (r < 0)
return r;
return safe_atou64(v, ret);
return cg_get_attribute_as_uint64("memory", u->cgroup_path, r > 0 ? "memory.current" : "memory.usage_in_bytes", ret);
}
int unit_get_tasks_current(Unit *u, uint64_t *ret) {
_cleanup_free_ char *v = NULL;
int r;
assert(u);
assert(ret);
@ -3166,17 +3135,10 @@ int unit_get_tasks_current(Unit *u, uint64_t *ret) {
if ((u->cgroup_realized_mask & CGROUP_MASK_PIDS) == 0)
return -ENODATA;
r = cg_get_attribute("pids", u->cgroup_path, "pids.current", &v);
if (r == -ENOENT)
return -ENODATA;
if (r < 0)
return r;
return safe_atou64(v, ret);
return cg_get_attribute_as_uint64("pids", u->cgroup_path, "pids.current", ret);
}
static int unit_get_cpu_usage_raw(Unit *u, nsec_t *ret) {
_cleanup_free_ char *v = NULL;
uint64_t ns;
int r;
@ -3212,17 +3174,8 @@ static int unit_get_cpu_usage_raw(Unit *u, nsec_t *ret) {
return r;
ns = us * NSEC_PER_USEC;
} else {
r = cg_get_attribute("cpuacct", u->cgroup_path, "cpuacct.usage", &v);
if (r == -ENOENT)
return -ENODATA;
if (r < 0)
return r;
r = safe_atou64(v, &ns);
if (r < 0)
return r;
}
} else
return cg_get_attribute_as_uint64("cpuacct", u->cgroup_path, "cpuacct.usage", ret);
*ret = ns;
return 0;