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Commit d40e48e0 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

exit: __exit_signal: use thread_group_leader() consistently 



Cleanup:

- Add the boolean, group_dead = thread_group_leader(), for clarity.

- Do not test/set sig == NULL to detect the all-dead case, use this
  boolean.

- Pass this boolen to __unhash_process() and use it instead of another
  thread_group_leader() call which needs ->group_leader.

  This can be considered as microoptimization, but hopefully this also
  allows us do do other cleanups later.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b7b8ff63

kernel/exit.c

+6 −6
Original line number Original line Diff line number Diff line
@@ -58,11 +58,11 @@ 




static void exit_mm(struct task_struct * tsk);

static void exit_mm(struct task_struct * tsk);





static void __unhash_process(struct task_struct *p)

static void __unhash_process(struct task_struct *p, bool group_dead)

{

{

	nr_threads--;

	nr_threads--;

	detach_pid(p, PIDTYPE_PID);

	detach_pid(p, PIDTYPE_PID);

	if (thread_group_leader(p)) {

	if (group_dead) {

		detach_pid(p, PIDTYPE_PGID);

		detach_pid(p, PIDTYPE_PGID);

		detach_pid(p, PIDTYPE_SID);

		detach_pid(p, PIDTYPE_SID);
@@ -79,6 +79,7 @@ static void __unhash_process(struct task_struct *p) 
static void __exit_signal(struct task_struct *tsk)

static void __exit_signal(struct task_struct *tsk)

{

{

	struct signal_struct *sig = tsk->signal;

	struct signal_struct *sig = tsk->signal;

	bool group_dead = thread_group_leader(tsk);

	struct sighand_struct *sighand;

	struct sighand_struct *sighand;

	struct tty_struct *uninitialized_var(tty);

	struct tty_struct *uninitialized_var(tty);
@@ -92,7 +93,7 @@ static void __exit_signal(struct task_struct *tsk) 
	atomic_dec(&sig->count);

	atomic_dec(&sig->count);





	posix_cpu_timers_exit(tsk);

	posix_cpu_timers_exit(tsk);

	if (thread_group_leader(tsk)) {

	if (group_dead) {

		posix_cpu_timers_exit_group(tsk);

		posix_cpu_timers_exit_group(tsk);

		tty = sig->tty;

		tty = sig->tty;

		sig->tty = NULL;

		sig->tty = NULL;
@@ -127,10 +128,9 @@ static void __exit_signal(struct task_struct *tsk) 
		sig->oublock += task_io_get_oublock(tsk);

		sig->oublock += task_io_get_oublock(tsk);

		task_io_accounting_add(&sig->ioac, &tsk->ioac);

		task_io_accounting_add(&sig->ioac, &tsk->ioac);

		sig->sum_sched_runtime += tsk->se.sum_exec_runtime;

		sig->sum_sched_runtime += tsk->se.sum_exec_runtime;

		sig = NULL; /* Marker for below. */

	}

	}





	__unhash_process(tsk);

	__unhash_process(tsk, group_dead);





	/*

	/*

	 * Do this under ->siglock, we can race with another thread

	 * Do this under ->siglock, we can race with another thread
@@ -142,7 +142,7 @@ static void __exit_signal(struct task_struct *tsk) 




	__cleanup_sighand(sighand);

	__cleanup_sighand(sighand);

	clear_tsk_thread_flag(tsk,TIF_SIGPENDING);

	clear_tsk_thread_flag(tsk,TIF_SIGPENDING);

	if (sig) {

	if (group_dead) {

		flush_sigqueue(&sig->shared_pending);

		flush_sigqueue(&sig->shared_pending);

		taskstats_tgid_free(sig);

		taskstats_tgid_free(sig);

		tty_kref_put(tty);

		tty_kref_put(tty);