From 47e65328a7b1cdfc4e3102e50d60faf94ebba7d3 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 28 Mar 2006 16:11:25 -0800 Subject: [PATCH] pids: kill PIDTYPE_TGID This patch kills PIDTYPE_TGID pid_type thus saving one hash table in kernel/pid.c and speeding up subthreads create/destroy a bit. It is also a preparation for the further tref/pids rework. This patch adds 'struct list_head thread_group' to 'struct task_struct' instead. We don't detach group leader from PIDTYPE_PID namespace until another thread inherits it's ->pid == ->tgid, so we are safe wrt premature free_pidmap(->tgid) call. Currently there are no users of find_task_by_pid_type(PIDTYPE_TGID). Should the need arise, we can use find_task_by_pid()->group_leader. Signed-off-by: Oleg Nesterov Acked-By: Eric Biederman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 12cdd9fc9d02..bc551efb5fd4 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1112,6 +1112,7 @@ static task_t *copy_process(unsigned long clone_flags, * We dont wake it up yet. */ p->group_leader = p; + INIT_LIST_HEAD(&p->thread_group); INIT_LIST_HEAD(&p->ptrace_children); INIT_LIST_HEAD(&p->ptrace_list); @@ -1165,7 +1166,9 @@ static task_t *copy_process(unsigned long clone_flags, retval = -EAGAIN; goto bad_fork_cleanup_namespace; } + p->group_leader = current->group_leader; + list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); if (current->signal->group_stop_count > 0) { /* @@ -1213,7 +1216,6 @@ static task_t *copy_process(unsigned long clone_flags, list_add_tail(&p->tasks, &init_task.tasks); __get_cpu_var(process_counts)++; } - attach_pid(p, PIDTYPE_TGID, p->tgid); attach_pid(p, PIDTYPE_PID, p->pid); nr_threads++; } -- cgit v1.2.3-55-g7522