From baa73d9e478ff32d62f3f9422822b59dd9a95a21 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Fri, 11 Nov 2016 00:10:10 -0500 Subject: posix-timers: Make them configurable Some embedded systems have no use for them. This removes about 25KB from the kernel binary size when configured out. Corresponding syscalls are routed to a stub logging the attempt to use those syscalls which should be enough of a clue if they were disabled without proper consideration. They are: timer_create, timer_gettime: timer_getoverrun, timer_settime, timer_delete, clock_adjtime, setitimer, getitimer, alarm. The clock_settime, clock_gettime, clock_getres and clock_nanosleep syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast majority of use cases with very little code. Signed-off-by: Nicolas Pitre Acked-by: Richard Cochran Acked-by: Thomas Gleixner Acked-by: John Stultz Reviewed-by: Josh Triplett Cc: Paul Bolle Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Michal Marek Cc: Edward Cree Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner --- kernel/exit.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index d16bcdd89dbe..684de019b674 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -92,11 +92,10 @@ static void __exit_signal(struct task_struct *tsk) lockdep_tasklist_lock_is_held()); spin_lock(&sighand->siglock); +#ifdef CONFIG_POSIX_TIMERS posix_cpu_timers_exit(tsk); if (group_dead) { posix_cpu_timers_exit_group(tsk); - tty = sig->tty; - sig->tty = NULL; } else { /* * This can only happen if the caller is de_thread(). @@ -105,7 +104,13 @@ static void __exit_signal(struct task_struct *tsk) */ if (unlikely(has_group_leader_pid(tsk))) posix_cpu_timers_exit_group(tsk); + } +#endif + if (group_dead) { + tty = sig->tty; + sig->tty = NULL; + } else { /* * If there is any task waiting for the group exit * then notify it: @@ -803,8 +808,10 @@ void __noreturn do_exit(long code) acct_update_integrals(tsk); group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { +#ifdef CONFIG_POSIX_TIMERS hrtimer_cancel(&tsk->signal->real_timer); exit_itimers(tsk->signal); +#endif if (tsk->mm) setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm); } -- cgit