/* * drivers/power/process.c - Functions for starting/stopping processes on * suspend transitions. * * Originally from swsusp. */ #undef DEBUG #include <linux/smp_lock.h> #include <linux/interrupt.h> #include <linux/suspend.h> #include <linux/module.h> /* * Timeout for stopping processes */ #define TIMEOUT (6 * HZ) static inline int freezeable(struct task_struct * p) { if ((p == current) || (p->flags & PF_NOFREEZE) || (p->exit_state == EXIT_ZOMBIE) || (p->exit_state == EXIT_DEAD) || (p->state == TASK_STOPPED) || (p->state == TASK_TRACED)) return 0; return 1; } /* Refrigerator is place where frozen processes are stored :-). */ void refrigerator(unsigned long flag) { /* Hmm, should we be allowed to suspend when there are realtime processes around? */ long save; save = current->state; current->state = TASK_UNINTERRUPTIBLE; pr_debug("%s entered refrigerator\n", current->comm); printk("="); current->flags &= ~PF_FREEZE; spin_lock_irq(¤t->sighand->siglock); recalc_sigpending(); /* We sent fake signal, clean it up */ spin_unlock_irq(¤t->sighand->siglock); current->flags |= PF_FROZEN; while (current->flags & PF_FROZEN) schedule(); pr_debug("%s left refrigerator\n", current->comm); current->state = save; } /* 0 = success, else # of processes that we failed to stop */ int freeze_processes(void) { int todo; unsigned long start_time; struct task_struct *g, *p; printk( "Stopping tasks: " ); start_time = jiffies; do { todo = 0; read_lock(&tasklist_lock); do_each_thread(g, p) { unsigned long flags; if (!freezeable(p)) continue; if ((p->flags & PF_FROZEN) || (p->state == TASK_TRACED) || (p->state == TASK_STOPPED)) continue; /* FIXME: smp problem here: we may not access other process' flags without locking */ p->flags |= PF_FREEZE; spin_lock_irqsave(&p->sighand->siglock, flags); signal_wake_up(p, 0); spin_unlock_irqrestore(&p->sighand->siglock, flags); todo++; } while_each_thread(g, p); read_unlock(&tasklist_lock); yield(); /* Yield is okay here */ if (time_after(jiffies, start_time + TIMEOUT)) { printk( "\n" ); printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo ); return todo; } } while(todo); printk( "|\n" ); BUG_ON(in_atomic()); return 0; } void thaw_processes(void) { struct task_struct *g, *p; printk( "Restarting tasks..." ); read_lock(&tasklist_lock); do_each_thread(g, p) { if (!freezeable(p)) continue; if (p->flags & PF_FROZEN) { p->flags &= ~PF_FROZEN; wake_up_process(p); } else printk(KERN_INFO " Strange, %s not stopped\n", p->comm ); } while_each_thread(g, p); read_unlock(&tasklist_lock); schedule(); printk( " done\n" ); } EXPORT_SYMBOL(refrigerator);