core: systemd-oomd pid1 integration

5 files changed, 62 insertions, 1 deletions

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 95b5f2de59..1958c1be2b 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -2681,6 +2681,47 @@ static void unit_remove_from_cgroup_empty_queue(Unit *u) {
         u->in_cgroup_empty_queue = false;
 }
 
+int unit_check_oomd_kill(Unit *u) {
+        _cleanup_free_ char *value = NULL;
+        bool increased;
+        uint64_t n = 0;
+        int r;
+
+        if (!u->cgroup_path)
+                return 0;
+
+        r = cg_all_unified();
+        if (r < 0)
+                return log_unit_debug_errno(u, r, "Couldn't determine whether we are in all unified mode: %m");
+        else if (r == 0)
+                return 0;
+
+        r = cg_get_xattr_malloc(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, "user.systemd_oomd_kill", &value);
+        if (r < 0 && r != -ENODATA)
+                return r;
+
+        if (!isempty(value)) {
+                 r = safe_atou64(value, &n);
+                 if (r < 0)
+                         return r;
+        }
+
+        increased = n > u->managed_oom_kill_last;
+        u->managed_oom_kill_last = n;
+
+        if (!increased)
+                return 0;
+
+        if (n > 0)
+                log_struct(LOG_NOTICE,
+                           "MESSAGE_ID=" SD_MESSAGE_UNIT_OOMD_KILL_STR,
+                           LOG_UNIT_ID(u),
+                           LOG_UNIT_INVOCATION_ID(u),
+                           LOG_UNIT_MESSAGE(u, "systemd-oomd killed %"PRIu64" process(es) in this unit.", n));
+
+        return 1;
+}
+
 int unit_check_oom(Unit *u) {
         _cleanup_free_ char *oom_kill = NULL;
         bool increased;
diff --git a/src/core/cgroup.h b/src/core/cgroup.h
index 1f592ef559..881b3f3dfe 100644
--- a/src/core/cgroup.h
+++ b/src/core/cgroup.h
@@ -229,6 +229,7 @@ int unit_watch_cgroup(Unit *u);
 int unit_watch_cgroup_memory(Unit *u);
 
 void unit_add_to_cgroup_empty_queue(Unit *u);
+int unit_check_oomd_kill(Unit *u);
 int unit_check_oom(Unit *u);
 
 int unit_attach_pids_to_cgroup(Unit *u, Set *pids, const char *suffix_path);
diff --git a/src/core/manager.c b/src/core/manager.c
index d85d938e7b..611ecf23b2 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -2578,6 +2578,11 @@ static int manager_dispatch_sigchld(sd_event_source *source, void *userdata) {
                          * We only do this for the cgroup the PID belonged to. */
                         (void) unit_check_oom(u1);
 
+                        /* This only logs for now. In the future when the interface for kills/notifications
+                         * is more stable we can extend service results table similar to how kernel oom kills
+                         * are managed. */
+                        (void) unit_check_oomd_kill(u1);
+
                         manager_invoke_sigchld_event(m, u1, &si);
                 }
                 if (u2)
diff --git a/src/core/unit.c b/src/core/unit.c
index 44b9f66e42..0792fd8ede 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -3571,6 +3571,9 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
         if (u->cpu_usage_last != NSEC_INFINITY)
                 (void) serialize_item_format(f, "cpu-usage-last", "%" PRIu64, u->cpu_usage_last);
 
+        if (u->managed_oom_kill_last > 0)
+                (void) serialize_item_format(f, "managed-oom-kill-last", "%" PRIu64, u->managed_oom_kill_last);
+
         if (u->oom_kill_last > 0)
                 (void) serialize_item_format(f, "oom-kill-last", "%" PRIu64, u->oom_kill_last);
 
@@ -3816,6 +3819,14 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
 
                         continue;
 
+                } else if (streq(l, "managed-oom-kill-last")) {
+
+                        r = safe_atou64(v, &u->managed_oom_kill_last);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to read managed OOM kill last %s, ignoring.", v);
+
+                        continue;
+
                 } else if (streq(l, "oom-kill-last")) {
 
                         r = safe_atou64(v, &u->oom_kill_last);
diff --git a/src/core/unit.h b/src/core/unit.h
index 9b2ea6c79f..1e6d7ccf6b 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -260,7 +260,10 @@ typedef struct Unit {
         nsec_t cpu_usage_base;
         nsec_t cpu_usage_last; /* the most recently read value */
 
-        /* The  current counter of the oom_kill field in the memory.events cgroup attribute */
+        /* The current counter of processes sent SIGKILL by systemd-oomd */
+        uint64_t managed_oom_kill_last;
+
+        /* The current counter of the oom_kill field in the memory.events cgroup attribute */
         uint64_t oom_kill_last;
 
         /* Where the io.stat data was at the time the unit was started */