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

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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.
This commit is contained in:
Augustin Cavalier
2025-01-06 23:39:40 -05:00
parent cc9746dbc6
commit 6a75e767e6
3 changed files with 31 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files
headers/private/kernel/thread_types.h
+12 -8
View File
@@ -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
// parent's fLock
DoublyLinkedListLink<Team> siblings_link; // protected by 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;
// adding/removing a child also requires the
// child's fLock
Team *group_next; // protected by the group's lock
DoublyLinkedList<Team, DoublyLinkedListMemberGetLink<Team, &Team::siblings_link> > children;
// protected by this team's fLock;
// adding/removing a child also requires the child's fLock
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
+1 -1
View File
@@ -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
+18 -49
View File
@@ -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 = team;
parent->children.Add(team, false);
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;
Team* last = 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;
}
parent->children.Remove(team);
team->parent = NULL;
}
@@ -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 = team;
group->teams.Add(team, false);
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;
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;
}
group->teams.Remove(team);
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;
child = child->siblings_next) {
for (Team* child = parent->children.First(); child != NULL;
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;
for (; child != NULL; child = child->siblings_next) {
Team* child = team->children.First();
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);