Merge pull request #9020 from poettering/physical-memory-cgroupsv2

make sure physical_memory() groks cgroupsv2

src/basic/util.c

@@ -405,6 +405,7 @@ uint64_t physical_memory(void) {
         uint64_t mem, lim;
         size_t ps;
         long sc;
+        int r;
 
         /* We return this as uint64_t in case we are running as 32bit process on a 64bit kernel with huge amounts of
          * memory.
@@ -418,13 +419,40 @@ uint64_t physical_memory(void) {
         ps = page_size();
         mem = (uint64_t) sc * (uint64_t) ps;
 
-        if (cg_get_root_path(&root) < 0)
+        r = cg_get_root_path(&root);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to determine root cgroup, ignoring cgroup memory limit: %m");
                 return mem;
+        }
 
-        if (cg_get_attribute("memory", root, "memory.limit_in_bytes", &value))
+        r = cg_all_unified();
+        if (r < 0) {
+                log_debug_errno(r, "Failed to determine root unified mode, ignoring cgroup memory limit: %m");
                 return mem;
+        }
+        if (r > 0) {
+                r = cg_get_attribute("memory", root, "memory.max", &value);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to read memory.max cgroup attribute, ignoring cgroup memory limit: %m");
+                        return mem;
+                }
 
-        if (safe_atou64(value, &lim) < 0)
+                if (streq(value, "max"))
+                        return mem;
+        } else {
+                r = cg_get_attribute("memory", root, "memory.limit_in_bytes", &value);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to read memory.limit_in_bytes cgroup attribute, ignoring cgroup memory limit: %m");
+                        return mem;
+                }
+        }
+
+        r = safe_atou64(value, &lim);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to parse cgroup memory limit '%s', ignoring: %m", value);
+                return mem;
+        }
+        if (lim == UINT64_MAX)
                 return mem;
 
         /* Make sure the limit is a multiple of our own page size */
@@ -465,6 +493,7 @@ uint64_t system_tasks_max(void) {
 
         uint64_t a = TASKS_MAX, b = TASKS_MAX;
         _cleanup_free_ char *root = NULL;
+        int r;
 
         /* Determine the maximum number of tasks that may run on this system. We check three sources to determine this
          * limit:
@@ -475,13 +504,24 @@ uint64_t system_tasks_max(void) {
          *
          * And then pick the smallest of the three */
 
-        (void) procfs_tasks_get_limit(&a);
+        r = procfs_tasks_get_limit(&a);
+        if (r < 0)
+                log_debug_errno(r, "Failed to read maximum number of tasks from /proc, ignoring: %m");
 
-        if (cg_get_root_path(&root) >= 0) {
+        r = cg_get_root_path(&root);
+        if (r < 0)
+                log_debug_errno(r, "Failed to determine cgroup root path, ignoring: %m");
+        else {
                 _cleanup_free_ char *value = NULL;
 
-                if (cg_get_attribute("pids", root, "pids.max", &value) >= 0)
-                        (void) safe_atou64(value, &b);
+                r = cg_get_attribute("pids", root, "pids.max", &value);
+                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,