X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fpower%2Fprocess.c;h=6d566bf7085c0b4fd7803a14cbaabef07269198e;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=bda013de59a51b0900821f63b41a3103d4ae664c;hpb=c7b5ebbddf7bcd3651947760f423e3783bbe6573;p=linux-2.6.git diff --git a/kernel/power/process.c b/kernel/power/process.c index bda013de5..6d566bf70 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -12,110 +12,208 @@ #include #include #include +#include +#include /* * Timeout for stopping processes */ -#define TIMEOUT (6 * HZ) +#define TIMEOUT (20 * HZ) +#define FREEZER_KERNEL_THREADS 0 +#define FREEZER_USER_SPACE 1 static inline int freezeable(struct task_struct * p) { if ((p == current) || (p->flags & PF_NOFREEZE) || - (p->state == TASK_ZOMBIE) || - (p->state == TASK_DEAD) || - (p->state == TASK_STOPPED) || - (p->state == TASK_TRACED)) + (p->exit_state == EXIT_ZOMBIE) || + (p->exit_state == EXIT_DEAD)) return 0; return 1; } /* Refrigerator is place where frozen processes are stored :-). */ -void refrigerator(unsigned long flag) +void refrigerator(void) { /* 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; + frozen_process(current); 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) + while (frozen(current)) { + current->state = TASK_UNINTERRUPTIBLE; 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) +static inline void freeze_process(struct task_struct *p) +{ + unsigned long flags; + + if (!freezing(p)) { + rmb(); + if (!frozen(p)) { + if (p->state == TASK_STOPPED) + force_sig_specific(SIGSTOP, p); + + freeze(p); + spin_lock_irqsave(&p->sighand->siglock, flags); + signal_wake_up(p, p->state == TASK_STOPPED); + spin_unlock_irqrestore(&p->sighand->siglock, flags); + } + } +} + +static void cancel_freezing(struct task_struct *p) +{ + unsigned long flags; + + if (freezing(p)) { + pr_debug(" clean up: %s\n", p->comm); + do_not_freeze(p); + spin_lock_irqsave(&p->sighand->siglock, flags); + recalc_sigpending_tsk(p); + spin_unlock_irqrestore(&p->sighand->siglock, flags); + } +} + +static inline int is_user_space(struct task_struct *p) +{ + return p->mm && !(p->flags & PF_BORROWED_MM); +} + +static unsigned int try_to_freeze_tasks(int freeze_user_space) { - int todo; - unsigned long start_time; struct task_struct *g, *p; - - printk( "Stopping tasks: " ); - start_time = jiffies; + unsigned long end_time; + unsigned int todo; + + end_time = jiffies + TIMEOUT; 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)) + + if (frozen(p)) 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); + if (p->state == TASK_TRACED && frozen(p->parent)) { + cancel_freezing(p); + continue; + } + if (is_user_space(p)) { + if (!freeze_user_space) + continue; + + /* Freeze the task unless there is a vfork + * completion pending + */ + if (!p->vfork_done) + freeze_process(p); + } else { + if (freeze_user_space) + continue; + + freeze_process(p); + } 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" ); + if (todo && time_after(jiffies, end_time)) + break; + } while (todo); + + if (todo) { + /* This does not unfreeze processes that are already frozen + * (we have slightly ugly calling convention in that respect, + * and caller must call thaw_processes() if something fails), + * but it cleans up leftover PF_FREEZE requests. + */ + printk("\n"); + printk(KERN_ERR "Stopping %s timed out after %d seconds " + "(%d tasks refusing to freeze):\n", + freeze_user_space ? "user space processes" : + "kernel threads", + TIMEOUT / HZ, todo); + read_lock(&tasklist_lock); + do_each_thread(g, p) { + if (is_user_space(p) == !freeze_user_space) + continue; + + if (freezeable(p) && !frozen(p)) + printk(KERN_ERR " %s\n", p->comm); + + cancel_freezing(p); + } while_each_thread(g, p); + read_unlock(&tasklist_lock); + } + + return todo; +} + +/** + * freeze_processes - tell processes to enter the refrigerator + * + * Returns 0 on success, or the number of processes that didn't freeze, + * although they were told to. + */ +int freeze_processes(void) +{ + unsigned int nr_unfrozen; + + printk("Stopping tasks ... "); + nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE); + if (nr_unfrozen) + return nr_unfrozen; + + sys_sync(); + nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); + if (nr_unfrozen) + return nr_unfrozen; + + printk("done.\n"); BUG_ON(in_atomic()); return 0; } -void thaw_processes(void) +static void thaw_tasks(int thaw_user_space) { 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); + if (is_user_space(p) == !thaw_user_space) + continue; + + if (!thaw_process(p)) + printk(KERN_WARNING " Strange, %s not stopped\n", + p->comm ); + } while_each_thread(g, p); read_unlock(&tasklist_lock); +} + +void thaw_processes(void) +{ + printk("Restarting tasks ... "); + thaw_tasks(FREEZER_KERNEL_THREADS); + thaw_tasks(FREEZER_USER_SPACE); schedule(); - printk( " done\n" ); + printk("done.\n"); } EXPORT_SYMBOL(refrigerator);