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[PATCH] de_thread: Use tsk not current
Ingo Oeser pointed out that because current expands to an inline function it is more space efficient and somewhat faster to simply keep a cached copy of current in another variable. This patch implements that for the de_thread function. (akpm: saves nearly 100 bytes of text on x86) Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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parent
66f37509fc
commit
aafe6c2a2b
46
fs/exec.c
46
fs/exec.c
@ -595,7 +595,7 @@ static int de_thread(struct task_struct *tsk)
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if (!newsighand)
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return -ENOMEM;
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if (thread_group_empty(current))
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if (thread_group_empty(tsk))
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goto no_thread_group;
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/*
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@ -620,17 +620,17 @@ static int de_thread(struct task_struct *tsk)
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* Reparenting needs write_lock on tasklist_lock,
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* so it is safe to do it under read_lock.
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*/
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if (unlikely(current->group_leader == child_reaper))
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child_reaper = current;
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if (unlikely(tsk->group_leader == child_reaper))
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child_reaper = tsk;
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zap_other_threads(current);
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zap_other_threads(tsk);
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read_unlock(&tasklist_lock);
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/*
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* Account for the thread group leader hanging around:
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*/
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count = 1;
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if (!thread_group_leader(current)) {
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if (!thread_group_leader(tsk)) {
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count = 2;
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/*
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* The SIGALRM timer survives the exec, but needs to point
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@ -639,14 +639,14 @@ static int de_thread(struct task_struct *tsk)
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* synchronize with any firing (by calling del_timer_sync)
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* before we can safely let the old group leader die.
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*/
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sig->tsk = current;
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sig->tsk = tsk;
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spin_unlock_irq(lock);
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if (hrtimer_cancel(&sig->real_timer))
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hrtimer_restart(&sig->real_timer);
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spin_lock_irq(lock);
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}
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while (atomic_read(&sig->count) > count) {
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sig->group_exit_task = current;
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sig->group_exit_task = tsk;
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sig->notify_count = count;
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__set_current_state(TASK_UNINTERRUPTIBLE);
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spin_unlock_irq(lock);
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@ -662,13 +662,13 @@ static int de_thread(struct task_struct *tsk)
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* do is to wait for the thread group leader to become inactive,
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* and to assume its PID:
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*/
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if (!thread_group_leader(current)) {
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if (!thread_group_leader(tsk)) {
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/*
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* Wait for the thread group leader to be a zombie.
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* It should already be zombie at this point, most
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* of the time.
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*/
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leader = current->group_leader;
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leader = tsk->group_leader;
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while (leader->exit_state != EXIT_ZOMBIE)
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yield();
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@ -682,12 +682,12 @@ static int de_thread(struct task_struct *tsk)
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* When we take on its identity by switching to its PID, we
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* also take its birthdate (always earlier than our own).
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*/
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current->start_time = leader->start_time;
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tsk->start_time = leader->start_time;
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write_lock_irq(&tasklist_lock);
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BUG_ON(leader->tgid != current->tgid);
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BUG_ON(current->pid == current->tgid);
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BUG_ON(leader->tgid != tsk->tgid);
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BUG_ON(tsk->pid == tsk->tgid);
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/*
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* An exec() starts a new thread group with the
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* TGID of the previous thread group. Rehash the
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@ -700,17 +700,17 @@ static int de_thread(struct task_struct *tsk)
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* Note: The old leader also uses this pid until release_task
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* is called. Odd but simple and correct.
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*/
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detach_pid(current, PIDTYPE_PID);
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current->pid = leader->pid;
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attach_pid(current, PIDTYPE_PID, current->pid);
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transfer_pid(leader, current, PIDTYPE_PGID);
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transfer_pid(leader, current, PIDTYPE_SID);
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list_replace_rcu(&leader->tasks, ¤t->tasks);
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detach_pid(tsk, PIDTYPE_PID);
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tsk->pid = leader->pid;
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attach_pid(tsk, PIDTYPE_PID, tsk->pid);
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transfer_pid(leader, tsk, PIDTYPE_PGID);
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transfer_pid(leader, tsk, PIDTYPE_SID);
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list_replace_rcu(&leader->tasks, &tsk->tasks);
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current->group_leader = current;
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leader->group_leader = current;
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tsk->group_leader = tsk;
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leader->group_leader = tsk;
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current->exit_signal = SIGCHLD;
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tsk->exit_signal = SIGCHLD;
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BUG_ON(leader->exit_state != EXIT_ZOMBIE);
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leader->exit_state = EXIT_DEAD;
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@ -750,7 +750,7 @@ static int de_thread(struct task_struct *tsk)
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spin_lock(&oldsighand->siglock);
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spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);
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rcu_assign_pointer(current->sighand, newsighand);
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rcu_assign_pointer(tsk->sighand, newsighand);
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recalc_sigpending();
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spin_unlock(&newsighand->siglock);
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@ -761,7 +761,7 @@ static int de_thread(struct task_struct *tsk)
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kmem_cache_free(sighand_cachep, oldsighand);
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}
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BUG_ON(!thread_group_leader(current));
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BUG_ON(!thread_group_leader(tsk));
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return 0;
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}
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