core: maintain a single table with event source priorities

It's hard to oversee the assigned processing priorities of the various
event sources we have. Let's unify them in a table (an enum), where we
can have a single consisten look at them, and then reference the table
entries by expressive symbols.

This doesn#t change behaviour in any way, it just gives each priority a
nice label, but doesn't change any of the priorities.

Prompted by: #30799

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index d5df93940b9dd79985bfc300e0e2233b293e913b..e7585c3c0189467dc749e971023a7b91a6f8f377 100644 (file)
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -3858,7 +3858,7 @@ static void unit_add_to_cgroup_oom_queue(Unit *u) {
                         return;
                 }
 
-                r = sd_event_source_set_priority(s, SD_EVENT_PRIORITY_NORMAL-8);
+                r = sd_event_source_set_priority(s, EVENT_PRIORITY_CGROUP_OOM);
                 if (r < 0) {
                         log_error_errno(r, "Failed to set priority of cgroup oom event source: %m");
                         return;
@@ -4064,7 +4064,7 @@ int manager_setup_cgroup(Manager *m) {
         /* Schedule cgroup empty checks early, but after having processed service notification messages or
          * SIGCHLD signals, so that a cgroup running empty is always just the last safety net of
          * notification, and we collected the metadata the notification and SIGCHLD stuff offers first. */
-        r = sd_event_source_set_priority(m->cgroup_empty_event_source, SD_EVENT_PRIORITY_NORMAL-5);
+        r = sd_event_source_set_priority(m->cgroup_empty_event_source, EVENT_PRIORITY_CGROUP_EMPTY);
         if (r < 0)
                 return log_error_errno(r, "Failed to set priority of cgroup empty event source: %m");
 
@@ -4093,7 +4093,7 @@ int manager_setup_cgroup(Manager *m) {
                 /* Process cgroup empty notifications early. Note that when this event is dispatched it'll
                  * just add the unit to a cgroup empty queue, hence let's run earlier than that. Also see
                  * handling of cgroup agent notifications, for the classic cgroup hierarchy support. */
-                r = sd_event_source_set_priority(m->cgroup_inotify_event_source, SD_EVENT_PRIORITY_NORMAL-9);
+                r = sd_event_source_set_priority(m->cgroup_inotify_event_source, EVENT_PRIORITY_CGROUP_INOTIFY);
                 if (r < 0)
                         return log_error_errno(r, "Failed to set priority of inotify event source: %m");
 

diff --git a/src/core/core-varlink.c b/src/core/core-varlink.c
index cd913817d2b897927c79d7406ba72460de51c4e6..10650421062a500412678b62f6004ae648132ffd 100644 (file)
--- a/src/core/core-varlink.c
+++ b/src/core/core-varlink.c
@@ -527,7 +527,7 @@ static int manager_varlink_init_system(Manager *m) {
                 }
         }
 
-        r = varlink_server_attach_event(s, m->event, SD_EVENT_PRIORITY_NORMAL);
+        r = varlink_server_attach_event(s, m->event, EVENT_PRIORITY_IPC);
         if (r < 0)
                 return log_error_errno(r, "Failed to attach varlink connection to event loop: %m");
 
@@ -585,7 +585,7 @@ static int manager_varlink_init_user(Manager *m) {
         if (r < 0)
                 return r;
 
-        r = varlink_attach_event(link, m->event, SD_EVENT_PRIORITY_NORMAL);
+        r = varlink_attach_event(link, m->event, EVENT_PRIORITY_IPC);
         if (r < 0)
                 return log_error_errno(r, "Failed to attach varlink connection to event loop: %m");
 

diff --git a/src/core/dbus.c b/src/core/dbus.c
index e24c5bbc53394140e9a5276b01d3642b9c8ad1e8..49a80bbcfa91a0900637837c5ca58980267d6ac0 100644 (file)
--- a/src/core/dbus.c
+++ b/src/core/dbus.c
@@ -739,7 +739,7 @@ static int bus_on_connection(sd_event_source *s, int fd, uint32_t revents, void
                 log_debug("Accepting direct incoming connection from " PID_FMT " (%s) [%s]", pid, strna(comm), strna(description));
         }
 
-        r = sd_bus_attach_event(bus, m->event, SD_EVENT_PRIORITY_NORMAL);
+        r = sd_bus_attach_event(bus, m->event, EVENT_PRIORITY_IPC);
         if (r < 0) {
                 log_warning_errno(r, "Failed to attach new connection bus to event loop: %m");
                 return 0;
@@ -847,7 +847,7 @@ int bus_init_api(Manager *m) {
                 if (r < 0)
                         return log_error_errno(r, "Failed to connect to API bus: %m");
 
-                r = sd_bus_attach_event(bus, m->event, SD_EVENT_PRIORITY_NORMAL);
+                r = sd_bus_attach_event(bus, m->event, EVENT_PRIORITY_IPC);
                 if (r < 0)
                         return log_error_errno(r, "Failed to attach API bus to event loop: %m");
 
@@ -904,7 +904,7 @@ int bus_init_system(Manager *m) {
                 if (r < 0)
                         return log_error_errno(r, "Failed to connect to system bus: %m");
 
-                r = sd_bus_attach_event(bus, m->event, SD_EVENT_PRIORITY_NORMAL);
+                r = sd_bus_attach_event(bus, m->event, EVENT_PRIORITY_IPC);
                 if (r < 0)
                         return log_error_errno(r, "Failed to attach system bus to event loop: %m");
 

diff --git a/src/core/manager.c b/src/core/manager.c
index 95c5f6381d3f26a27c033e472f62e995df433a39..e052e36cee65f0c6bfb97361509f4e7e5fb38220 100644 (file)
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -397,7 +397,7 @@ static int manager_setup_time_change(Manager *m) {
                 return log_error_errno(r, "Failed to create time change event source: %m");
 
         /* Schedule this slightly earlier than the .timer event sources */
-        r = sd_event_source_set_priority(m->time_change_event_source, SD_EVENT_PRIORITY_NORMAL-1);
+        r = sd_event_source_set_priority(m->time_change_event_source, EVENT_PRIORITY_TIME_CHANGE);
         if (r < 0)
                 return log_error_errno(r, "Failed to set priority of time change event sources: %m");
 
@@ -464,7 +464,7 @@ static int manager_setup_timezone_change(Manager *m) {
                 return log_error_errno(r, "Failed to create timezone change event source: %m");
 
         /* Schedule this slightly earlier than the .timer event sources */
-        r = sd_event_source_set_priority(new_event, SD_EVENT_PRIORITY_NORMAL-1);
+        r = sd_event_source_set_priority(new_event, EVENT_PRIORITY_TIME_ZONE);
         if (r < 0)
                 return log_error_errno(r, "Failed to set priority of timezone change event sources: %m");
 
@@ -592,7 +592,7 @@ static int manager_setup_signals(Manager *m) {
          * notify processing can still figure out to which process/service a message belongs, before we reap the
          * process. Also, process this before handling cgroup notifications, so that we always collect child exit
          * status information before detecting that there's no process in a cgroup. */
-        r = sd_event_source_set_priority(m->signal_event_source, SD_EVENT_PRIORITY_NORMAL-6);
+        r = sd_event_source_set_priority(m->signal_event_source, EVENT_PRIORITY_SIGNALS);
         if (r < 0)
                 return r;
 
@@ -736,7 +736,7 @@ static int manager_setup_run_queue(Manager *m) {
         if (r < 0)
                 return r;
 
-        r = sd_event_source_set_priority(m->run_queue_event_source, SD_EVENT_PRIORITY_IDLE);
+        r = sd_event_source_set_priority(m->run_queue_event_source, EVENT_PRIORITY_RUN_QUEUE);
         if (r < 0)
                 return r;
 
@@ -759,7 +759,7 @@ static int manager_setup_sigchld_event_source(Manager *m) {
         if (r < 0)
                 return r;
 
-        r = sd_event_source_set_priority(m->sigchld_event_source, SD_EVENT_PRIORITY_NORMAL-7);
+        r = sd_event_source_set_priority(m->sigchld_event_source, EVENT_PRIORITY_SIGCHLD);
         if (r < 0)
                 return r;
 
@@ -1113,7 +1113,7 @@ static int manager_setup_notify(Manager *m) {
 
                 /* Process notification messages a bit earlier than SIGCHLD, so that we can still identify to which
                  * service an exit message belongs. */
-                r = sd_event_source_set_priority(m->notify_event_source, SD_EVENT_PRIORITY_NORMAL-8);
+                r = sd_event_source_set_priority(m->notify_event_source, EVENT_PRIORITY_NOTIFY);
                 if (r < 0)
                         return log_error_errno(r, "Failed to set priority of notify event source: %m");
 
@@ -1187,7 +1187,7 @@ static int manager_setup_cgroups_agent(Manager *m) {
                 /* Process cgroups notifications early. Note that when the agent notification is received
                  * we'll just enqueue the unit in the cgroup empty queue, hence pick a high priority than
                  * that. Also see handling of cgroup inotify for the unified cgroup stuff. */
-                r = sd_event_source_set_priority(m->cgroups_agent_event_source, SD_EVENT_PRIORITY_NORMAL-9);
+                r = sd_event_source_set_priority(m->cgroups_agent_event_source, EVENT_PRIORITY_CGROUP_AGENT);
                 if (r < 0)
                         return log_error_errno(r, "Failed to set priority of cgroups agent event source: %m");
 
@@ -1240,7 +1240,7 @@ static int manager_setup_user_lookup_fd(Manager *m) {
 
                 /* Process even earlier than the notify event source, so that we always know first about valid UID/GID
                  * resolutions */
-                r = sd_event_source_set_priority(m->user_lookup_event_source, SD_EVENT_PRIORITY_NORMAL-11);
+                r = sd_event_source_set_priority(m->user_lookup_event_source, EVENT_PRIORITY_USER_LOOKUP);
                 if (r < 0)
                         return log_error_errno(errno, "Failed to set priority of user lookup event source: %m");
 

diff --git a/src/core/manager.h b/src/core/manager.h
index d7bc6e761d40ce740a601fc2540ffc2f7c28886d..cfcf1929f544504de1732b18f2f2870c33ea9e43 100644 (file)
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -644,3 +644,25 @@ OOMPolicy oom_policy_from_string(const char *s) _pure_;
 
 void unit_defaults_init(UnitDefaults *defaults, RuntimeScope scope);
 void unit_defaults_done(UnitDefaults *defaults);
+
+enum {
+        /* most important … */
+        EVENT_PRIORITY_USER_LOOKUP      = SD_EVENT_PRIORITY_NORMAL-11,
+        EVENT_PRIORITY_MOUNT_TABLE      = SD_EVENT_PRIORITY_NORMAL-10,
+        EVENT_PRIORITY_SWAP_TABLE       = SD_EVENT_PRIORITY_NORMAL-10,
+        EVENT_PRIORITY_CGROUP_AGENT     = SD_EVENT_PRIORITY_NORMAL-9,
+        EVENT_PRIORITY_CGROUP_INOTIFY   = SD_EVENT_PRIORITY_NORMAL-9,
+        EVENT_PRIORITY_CGROUP_OOM       = SD_EVENT_PRIORITY_NORMAL-8,
+        EVENT_PRIORITY_NOTIFY           = SD_EVENT_PRIORITY_NORMAL-8,
+        EVENT_PRIORITY_SIGCHLD          = SD_EVENT_PRIORITY_NORMAL-7,
+        EVENT_PRIORITY_SIGNALS          = SD_EVENT_PRIORITY_NORMAL-6,
+        EVENT_PRIORITY_CGROUP_EMPTY     = SD_EVENT_PRIORITY_NORMAL-5,
+        EVENT_PRIORITY_EXEC_FD          = SD_EVENT_PRIORITY_NORMAL-3,
+        EVENT_PRIORITY_TIME_CHANGE      = SD_EVENT_PRIORITY_NORMAL-1,
+        EVENT_PRIORITY_TIME_ZONE        = SD_EVENT_PRIORITY_NORMAL-1,
+        EVENT_PRIORITY_IPC              = SD_EVENT_PRIORITY_NORMAL,
+        EVENT_PRIORITY_REWATCH_PIDS     = SD_EVENT_PRIORITY_IDLE,
+        EVENT_PRIORITY_RUN_QUEUE        = SD_EVENT_PRIORITY_IDLE,
+        EVENT_PRIORITY_SERVICE_WATCHDOG = SD_EVENT_PRIORITY_IDLE,
+        /* … to least important */
+};

diff --git a/src/core/mount.c b/src/core/mount.c
index ff97eebb597fd64bf1d757e7e3cfc055da96c907..048802fa1be85e230d88f945d75c8ef5a4891841 100644 (file)
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -2090,7 +2090,7 @@ static void mount_enumerate(Manager *m) {
                         goto fail;
                 }
 
-                r = sd_event_source_set_priority(m->mount_event_source, SD_EVENT_PRIORITY_NORMAL-10);
+                r = sd_event_source_set_priority(m->mount_event_source, EVENT_PRIORITY_MOUNT_TABLE);
                 if (r < 0) {
                         log_error_errno(r, "Failed to adjust mount watch priority: %m");
                         goto fail;

diff --git a/src/core/service.c b/src/core/service.c
index a4c9f80e04de194ab0b6e676f76a9ea0267883fd..79859a2a1ea26b601be3679d8594284b3896ed6e 100644 (file)
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -291,7 +291,7 @@ static void service_start_watchdog(Service *s) {
 
                 /* Let's process everything else which might be a sign
                  * of living before we consider a service died. */
-                r = sd_event_source_set_priority(s->watchdog_event_source, SD_EVENT_PRIORITY_IDLE);
+                r = sd_event_source_set_priority(s->watchdog_event_source, EVENT_PRIORITY_SERVICE_WATCHDOG);
         }
         if (r < 0)
                 log_unit_warning_errno(UNIT(s), r, "Failed to install watchdog timer: %m");
@@ -1514,7 +1514,7 @@ static int service_allocate_exec_fd_event_source(
 
         /* This is a bit lower priority than SIGCHLD, as that carries a lot more interesting failure information */
 
-        r = sd_event_source_set_priority(source, SD_EVENT_PRIORITY_NORMAL-3);
+        r = sd_event_source_set_priority(source, EVENT_PRIORITY_EXEC_FD);
         if (r < 0)
                 return log_unit_error_errno(UNIT(s), r, "Failed to adjust priority of exec_fd event source: %m");
 

diff --git a/src/core/swap.c b/src/core/swap.c
index ce35a5c4413adcad0c1dd06e78c765944b9e7be4..9f7c12b0c3cf12c73ab7d2e9b0a0f86280536861 100644 (file)
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -1358,7 +1358,7 @@ static void swap_enumerate(Manager *m) {
                 /* Dispatch this before we dispatch SIGCHLD, so that
                  * we always get the events from /proc/swaps before
                  * the SIGCHLD of /sbin/swapon. */
-                r = sd_event_source_set_priority(m->swap_event_source, SD_EVENT_PRIORITY_NORMAL-10);
+                r = sd_event_source_set_priority(m->swap_event_source, EVENT_PRIORITY_SWAP_TABLE);
                 if (r < 0) {
                         log_error_errno(r, "Failed to change /proc/swaps priority: %m");
                         goto fail;

diff --git a/src/core/unit.c b/src/core/unit.c
index 49b45b21406bf4739c0922930b0ad47744da817e..d9e67067425811765c829db3c9326fc0104c252a 100644 (file)
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2992,7 +2992,7 @@ int unit_enqueue_rewatch_pids(Unit *u) {
                 if (r < 0)
                         return log_error_errno(r, "Failed to allocate event source for tidying watched PIDs: %m");
 
-                r = sd_event_source_set_priority(s, SD_EVENT_PRIORITY_IDLE);
+                r = sd_event_source_set_priority(s, EVENT_PRIORITY_REWATCH_PIDS);
                 if (r < 0)
                         return log_error_errno(r, "Failed to adjust priority of event source for tidying watched PIDs: %m");