Messages in this thread Patch in this message | | | Date | Sun, 9 Apr 2006 04:11:27 +0400 | From | Oleg Nesterov <> | Subject | [PATCH rc1-mm 2/3] coredump: shutdown current process first |
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This patch optimize zap_threads() for the case when there are no ->mm users except the current's thread group. In that case we can avoid 'for_each_process()' loop.
It also adds a useful invariant: SIGNAL_GROUP_EXIT (if checked under ->siglock) always implies that all threads (except may be current) have pending SIGKILL.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- MM/fs/exec.c~2_optmz 2006-04-09 02:33:28.000000000 +0400 +++ MM/fs/exec.c 2006-04-09 03:06:43.000000000 +0400 @@ -1383,13 +1383,7 @@ static void format_corename(char *corena static void zap_process(struct task_struct *start) { struct task_struct *t; - unsigned long flags; - /* - * start->sighand can't disappear, but may be - * changed by de_thread() - */ - lock_task_sighand(start, &flags); start->signal->flags = SIGNAL_GROUP_EXIT; start->signal->group_stop_count = 0; @@ -1401,40 +1395,51 @@ static void zap_process(struct task_stru signal_wake_up(t, 1); } } while ((t = next_thread(t)) != start); - - unlock_task_sighand(start, &flags); } static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, int exit_code) { struct task_struct *g, *p; + unsigned long flags; int err = -EAGAIN; spin_lock_irq(&tsk->sighand->siglock); if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) { - tsk->signal->flags = SIGNAL_GROUP_EXIT; tsk->signal->group_exit_code = exit_code; - tsk->signal->group_stop_count = 0; + zap_process(tsk); err = 0; } spin_unlock_irq(&tsk->sighand->siglock); if (err) return err; + if (atomic_read(&mm->mm_users) == mm->core_waiters + 1) + goto done; + rcu_read_lock(); for_each_process(g) { + if (g == tsk->group_leader) + continue; + p = g; do { if (p->mm) { - if (p->mm == mm) + if (p->mm == mm) { + /* + * p->sighand can't disappear, but + * may be changed by de_thread() + */ + lock_task_sighand(p, &flags); zap_process(p); + unlock_task_sighand(p, &flags); + } break; } } while ((p = next_thread(p)) != g); } rcu_read_unlock(); - +done: return mm->core_waiters; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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