kernel/team: Convert Team linked-lists into DoublyLinkedLists.

They were hand-rolled singly-linked lists before. This adds 24 bytes
of size to the Team structure, but turns all the removal operations
in parent and process group into O(1) operations instead of O(N) ones.
Realistically, the Thread linked-lists should be converted as well,
but this is trickier due to interdependence on the Team structure.

headers/private/kernel/thread_types.h

@@ -220,14 +220,13 @@ struct Team : TeamThreadIteratorEntry<team_id>, KernelReferenceable,
 		AssociatedDataOwner {
 	DoublyLinkedListLink<Team>	global_list_link;
 	Team			*hash_next;		// next in hash
-	Team			*siblings_next;	// next in parent's list; protected by
+	DoublyLinkedListLink<Team> siblings_link; // protected by parent's fLock
-									// parent's fLock
 	Team			*parent;		// write-protected by both parent (if any)
 									// and this team's fLock
-	Team			*children;		// protected by this team's fLock;
+	DoublyLinkedList<Team, DoublyLinkedListMemberGetLink<Team, &Team::siblings_link> > children;
-									// adding/removing a child also requires the
+		// protected by this team's fLock;
-									// child's fLock
+		// adding/removing a child also requires the child's fLock
-	Team			*group_next;	// protected by the group's lock
+	DoublyLinkedListLink<Team> group_link; // protected by the group's lock
 
 	int64			serial_number;	// immutable after adding team to hash
 
@@ -667,9 +666,14 @@ private:
 
 
 struct ProcessGroup : KernelReferenceable {
-	struct ProcessGroup *next;		// next in hash
+	typedef DoublyLinkedList<Team,
+		DoublyLinkedListMemberGetLink<Team,
+			&Team::group_link> > TeamList;
+
+public:
+	struct ProcessGroup *hash_next;
 	pid_t				id;
-	BKernel::Team		*teams;
+	TeamList			teams;
 
 public:
 								ProcessGroup(pid_t id);

src/system/kernel/signal.cpp

@@ -1828,7 +1828,7 @@ send_signal_to_process_group_locked(ProcessGroup* group, const Signal& signal,
 
 	bool firstTeam = true;
 
-	for (Team* team = group->teams; team != NULL; team = team->group_next) {
+	for (Team* team = group->teams.First(); team != NULL; team = group->teams.GetNext(team)) {
 		status_t error = send_signal_to_team(team, signal,
 			flags | B_DO_NOT_RESCHEDULE);
 		// If sending to the first team in the group failed, let the whole call

src/system/kernel/team.cpp

@@ -132,7 +132,7 @@ struct ProcessGroupHashDefinition {
 
 	ProcessGroup*& GetLink(ProcessGroup* value) const
 	{
-		return value->next;
+		return value->hash_next;
 	}
 };
 
@@ -431,7 +431,7 @@ Team::Team(team_id id, bool kernel)
 	this->id = id;
 	visible = true;
 
-	hash_next = siblings_next = parent = children = group_next = NULL;
+	hash_next = parent = NULL;
 	serial_number = -1;
 
 	group_id = session_id = -1;
@@ -990,7 +990,6 @@ Team::UserCPUTime() const
 ProcessGroup::ProcessGroup(pid_t id)
 	:
 	id(id),
-	teams(NULL),
 	fSession(NULL),
 	fInOrphanedCheckList(false)
 {
@@ -1074,7 +1073,7 @@ ProcessGroup::IsOrphaned() const
 	// group's session." (Open Group Base Specs Issue 7)
 	bool orphaned = true;
 
-	Team* team = teams;
+	Team* team = teams.First();
 	while (orphaned && team != NULL) {
 		team->LockTeamAndParent(false);
 
@@ -1086,7 +1085,7 @@ ProcessGroup::IsOrphaned() const
 
 		team->UnlockTeamAndParent();
 
-		team = team->group_next;
+		team = teams.GetNext(team);
 	}
 
 	return orphaned;
@@ -1152,7 +1151,7 @@ _dump_team_info(Team* team)
 	} else
 		kprintf("\n");
 
-	kprintf("children:         %p\n", team->children);
+	kprintf("children:         %p\n", team->children.First());
 	kprintf("num_threads:      %d\n", team->num_threads);
 	kprintf("state:            %d\n", team->state);
 	kprintf("flags:            0x%" B_PRIx32 "\n", team->flags);
@@ -1282,8 +1281,7 @@ insert_team_into_parent(Team* parent, Team* team)
 {
 	ASSERT(parent != NULL);
 
-	team->siblings_next = parent->children;
+	parent->children.Add(team, false);
-	parent->children = team;
 	team->parent = parent;
 }
 
@@ -1298,22 +1296,8 @@ insert_team_into_parent(Team* parent, Team* team)
 static void
 remove_team_from_parent(Team* parent, Team* team)
 {
-	Team* child;
+	parent->children.Remove(team);
-	Team* last = NULL;
+	team->parent = NULL;
-
-	for (child = parent->children; child != NULL;
-			child = child->siblings_next) {
-		if (child == team) {
-			if (last == NULL)
-				parent->children = child->siblings_next;
-			else
-				last->siblings_next = child->siblings_next;
-
-			team->parent = NULL;
-			break;
-		}
-		last = child;
-	}
 }
 
 
@@ -1348,8 +1332,7 @@ insert_team_into_group(ProcessGroup* group, Team* team)
 	team->group_id = group->id;
 	team->session_id = group->Session()->id;
 
-	team->group_next = group->teams;
+	group->teams.Add(team, false);
-	group->teams = team;
 	group->AcquireReference();
 }
 
@@ -1365,28 +1348,14 @@ static void
 remove_team_from_group(Team* team)
 {
 	ProcessGroup* group = team->group;
-	Team* current;
-	Team* last = NULL;
 
 	// the team must be in a process group to let this function have any effect
 	if (group == NULL)
 		return;
 
-	for (current = group->teams; current != NULL;
+	group->teams.Remove(team);
-			current = current->group_next) {
-		if (current == team) {
-			if (last == NULL)
-				group->teams = current->group_next;
-			else
-				last->group_next = current->group_next;
-
-			break;
-		}
-		last = current;
-	}
 
 	team->group = NULL;
-	team->group_next = NULL;
 	team->group_id = -1;
 
 	group->ReleaseReference();
@@ -2329,8 +2298,8 @@ err1:
 static bool
 has_children_in_group(Team* parent, pid_t groupID)
 {
-	for (Team* child = parent->children; child != NULL;
+	for (Team* child = parent->children.First(); child != NULL;
-			child = child->siblings_next) {
+			child = parent->children.GetNext(child)) {
 		TeamLocker childLocker(child);
 		if (child->group_id == groupID)
 			return true;
@@ -2534,7 +2503,7 @@ wait_for_child(pid_t child, uint32 flags, siginfo_t& _info,
 			// to the process group specification at all.
 			bool childrenExist = false;
 			if (child == -1) {
-				childrenExist = team->children != NULL;
+				childrenExist = !team->children.IsEmpty();
 			} else if (child < -1) {
 				childrenExist = has_children_in_group(team, -child);
 			} else if (child != team->id) {
@@ -2734,7 +2703,7 @@ fill_team_info(Team* team, team_info* info, size_t size)
 static bool
 process_group_has_stopped_processes(ProcessGroup* group)
 {
-	Team* team = group->teams;
+	Team* team = group->teams.First();
 	while (team != NULL) {
 		// the parent team's lock guards the job control entry -- acquire it
 		team->LockTeamAndParent(false);
@@ -2747,7 +2716,7 @@ process_group_has_stopped_processes(ProcessGroup* group)
 
 		team->UnlockTeamAndParent();
 
-		team = team->group_next;
+		team = group->teams.GetNext(team);
 	}
 
 	return false;
@@ -2833,8 +2802,8 @@ common_get_team_usage_info(team_id id, int32 who, team_usage_info* info,
 
 		case B_TEAM_USAGE_CHILDREN:
 		{
-			Team* child = team->children;
+			Team* child = team->children.First();
-			for (; child != NULL; child = child->siblings_next) {
+			for (; child != NULL; child = team->children.GetNext(team)) {
 				TeamLocker childLocker(child);
 
 				Thread* thread = team->thread_list;
@@ -3160,7 +3129,7 @@ team_remove_team(Team* team, pid_t& _signalGroup)
 	remove_team_from_group(team);
 
 	// move the team's children to the kernel team
-	while (Team* child = team->children) {
+	while (Team* child = team->children.First()) {
 		// remove the child from the current team and add it to the kernel team
 		TeamLocker childLocker(child);