manager: fix GC algorithm

[elogind.git] / unit.h

diff --git a/unit.h b/unit.h
index 76aa0eff5f46676139df7a1e77fd91d9ffa2dee8..689dc00e31e3a33fff8cd604e709ae3194e4d9b2 100644 (file)
--- a/unit.h
+++ b/unit.h
@@ -113,9 +113,13 @@ enum UnitDependency {
         UNIT_CONFLICTS,               /* inverse of 'conflicts' is 'conflicts' */
 
         /* Order */
-        UNIT_BEFORE,                  /* inverse of before is after and vice versa */
+        UNIT_BEFORE,                  /* inverse of 'before' is 'after' and vice versa */
         UNIT_AFTER,
 
+        /* Reference information for GC logic */
+        UNIT_REFERENCES,              /* Inverse of 'references' is 'referenced_by' */
+        UNIT_REFERENCED_BY,
+
         _UNIT_DEPENDENCY_MAX,
         _UNIT_DEPENDENCY_INVALID = -1
 };
@@ -144,34 +148,42 @@ struct Meta {
          * the job for it */
         Job *job;
 
-        bool in_load_queue:1;
-        bool in_dbus_queue:1;
-        bool in_cleanup_queue:1;
-        bool sent_dbus_new_signal:1;
-
-        /* If we go down, pull down everything that depends on us, too */
-        bool recursive_stop;
-
-        /* Garbage collect us we nobody wants or requires us anymore */
-        bool stop_when_unneeded;
-
         usec_t active_enter_timestamp;
         usec_t active_exit_timestamp;
 
         /* Counterparts in the cgroup filesystem */
         CGroupBonding *cgroup_bondings;
 
-        /* Load queue */
-        LIST_FIELDS(Meta, load_queue);
-
         /* Per type list */
         LIST_FIELDS(Meta, units_per_type);
 
+        /* Load queue */
+        LIST_FIELDS(Meta, load_queue);
+
         /* D-Bus queue */
         LIST_FIELDS(Meta, dbus_queue);
 
         /* Cleanup queue */
         LIST_FIELDS(Meta, cleanup_queue);
+
+        /* GC queue */
+        LIST_FIELDS(Meta, gc_queue);
+
+        /* Used during GC sweeps */
+        unsigned gc_marker;
+
+        /* If we go down, pull down everything that depends on us, too */
+        bool recursive_stop;
+
+        /* Garbage collect us we nobody wants or requires us anymore */
+        bool stop_when_unneeded;
+
+        bool in_load_queue:1;
+        bool in_dbus_queue:1;
+        bool in_cleanup_queue:1;
+        bool in_gc_queue:1;
+
+        bool sent_dbus_new_signal:1;
 };
 
 #include "service.h"
@@ -198,20 +210,6 @@ union Unit {
 struct UnitVTable {
         const char *suffix;
 
-        /* Can units of this type have multiple names? */
-        bool no_alias:1;
-
-        /* If true units of this types can never have "Requires"
-         * dependencies, because state changes can only be observed,
-         * not triggered */
-        bool no_requires:1;
-
-        /* Instances make no sense for this type */
-        bool no_instances:1;
-
-        /* Exclude this type from snapshots */
-        bool no_snapshots:1;
-
         /* This should reset all type-specific variables. This should
          * not allocate memory, and is called with zero-initialized
          * data. It should hence only initialize variables that need
@@ -256,6 +254,14 @@ struct UnitVTable {
          * unit is in. */
         const char* (*sub_state_to_string)(Unit *u);
 
+        /* Return true when there is reason to keep this entry around
+         * even nothing references it and it isn't active in any
+         * way */
+        bool (*check_gc)(Unit *u);
+
+        /* Return true when this unit is suitable for snapshotting */
+        bool (*check_snapshot)(Unit *u);
+
         void (*fd_event)(Unit *u, int fd, uint32_t events, Watch *w);
         void (*sigchld_event)(Unit *u, pid_t pid, int code, int status);
         void (*timer_event)(Unit *u, uint64_t n_elapsed, Watch *w);
@@ -283,6 +289,26 @@ struct UnitVTable {
 
         /* Type specific cleanups. */
         void (*shutdown)(Manager *m);
+
+        /* Can units of this type have multiple names? */
+        bool no_alias:1;
+
+        /* If true units of this types can never have "Requires"
+         * dependencies, because state changes can only be observed,
+         * not triggered */
+        bool no_requires:1;
+
+        /* Instances make no sense for this type */
+        bool no_instances:1;
+
+        /* Exclude this type from snapshots */
+        bool no_snapshots:1;
+
+        /* Exclude from automatic gc */
+        bool no_gc:1;
+
+        /* Exclude from isolation requests */
+        bool no_isolate:1;
 };
 
 extern const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX];
@@ -315,9 +341,9 @@ void unit_free(Unit *u);
 
 int unit_add_name(Unit *u, const char *name);
 
-int unit_add_dependency(Unit *u, UnitDependency d, Unit *other);
-int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, const char *filename);
-int unit_add_dependency_by_name_inverse(Unit *u, UnitDependency d, const char *name, const char *filename);
+int unit_add_dependency(Unit *u, UnitDependency d, Unit *other, bool add_reference);
+int unit_add_dependency_by_name(Unit *u, UnitDependency d, const char *name, const char *filename, bool add_reference);
+int unit_add_dependency_by_name_inverse(Unit *u, UnitDependency d, const char *name, const char *filename, bool add_reference);
 
 int unit_add_exec_dependencies(Unit *u, ExecContext *c);
 
@@ -329,9 +355,12 @@ CGroupBonding* unit_get_default_cgroup(Unit *u);
 int unit_choose_id(Unit *u, const char *name);
 int unit_set_description(Unit *u, const char *description);
 
+bool unit_check_gc(Unit *u);
+
 void unit_add_to_load_queue(Unit *u);
 void unit_add_to_dbus_queue(Unit *u);
 void unit_add_to_cleanup_queue(Unit *u);
+void unit_add_to_gc_queue(Unit *u);
 
 int unit_merge(Unit *u, Unit *other);
 int unit_merge_by_name(Unit *u, const char *other);