X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fpower%2Fprocess.c;h=6533923e711b5dd8be01efd5f1e9576250ebf42f;hb=c8b1ef88d09961078d3c685fcdc1d1659db05231;hp=e0233d8422b9ed4ec9d62ce1f54bd65165931daa;hpb=55663219378eecd6fccb319be27ce6737a535e4c;p=linux-2.6 diff --git a/kernel/power/process.c b/kernel/power/process.c index e0233d8422..6533923e71 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -40,7 +40,7 @@ static inline void frozen_process(void) current->flags |= PF_FROZEN; wmb(); } - clear_tsk_thread_flag(current, TIF_FREEZE); + clear_freeze_flag(current); } /* Refrigerator is place where frozen processes are stored :-). */ @@ -72,25 +72,82 @@ void refrigerator(void) schedule(); } pr_debug("%s left refrigerator\n", current->comm); - current->state = save; + __set_current_state(save); } -static inline void freeze_process(struct task_struct *p) +static void fake_signal_wake_up(struct task_struct *p, int resume) { unsigned long flags; - if (!freezing(p)) { + spin_lock_irqsave(&p->sighand->siglock, flags); + signal_wake_up(p, resume); + spin_unlock_irqrestore(&p->sighand->siglock, flags); +} + +static void send_fake_signal(struct task_struct *p) +{ + if (p->state == TASK_STOPPED) + force_sig_specific(SIGSTOP, p); + fake_signal_wake_up(p, p->state == TASK_STOPPED); +} + +static int has_mm(struct task_struct *p) +{ + return (p->mm && !(p->flags & PF_BORROWED_MM)); +} + +/** + * freeze_task - send a freeze request to given task + * @p: task to send the request to + * @with_mm_only: if set, the request will only be sent if the task has its + * own mm + * Return value: 0, if @with_mm_only is set and the task has no mm of its + * own or the task is frozen, 1, otherwise + * + * The freeze request is sent by seting the tasks's TIF_FREEZE flag and + * either sending a fake signal to it or waking it up, depending on whether + * or not it has its own mm (ie. it is a user land task). If @with_mm_only + * is set and the task has no mm of its own (ie. it is a kernel thread), + * its TIF_FREEZE flag should not be set. + * + * The task_lock() is necessary to prevent races with exit_mm() or + * use_mm()/unuse_mm() from occuring. + */ +static int freeze_task(struct task_struct *p, int with_mm_only) +{ + int ret = 1; + + task_lock(p); + if (freezing(p)) { + if (has_mm(p)) { + if (!signal_pending(p)) + fake_signal_wake_up(p, 0); + } else { + if (with_mm_only) + ret = 0; + else + wake_up_state(p, TASK_INTERRUPTIBLE); + } + } else { 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); + if (frozen(p)) { + ret = 0; + } else { + if (has_mm(p)) { + set_freeze_flag(p); + send_fake_signal(p); + } else { + if (with_mm_only) { + ret = 0; + } else { + set_freeze_flag(p); + wake_up_state(p, TASK_INTERRUPTIBLE); + } + } } } + task_unlock(p); + return ret; } static void cancel_freezing(struct task_struct *p) @@ -99,52 +156,54 @@ static void cancel_freezing(struct task_struct *p) if (freezing(p)) { pr_debug(" clean up: %s\n", p->comm); - do_not_freeze(p); + clear_freeze_flag(p); spin_lock_irqsave(&p->sighand->siglock, flags); recalc_sigpending_and_wake(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) +static int try_to_freeze_tasks(int freeze_user_space) { struct task_struct *g, *p; unsigned long end_time; unsigned int todo; + struct timeval start, end; + s64 elapsed_csecs64; + unsigned int elapsed_csecs; + + do_gettimeofday(&start); end_time = jiffies + TIMEOUT; do { todo = 0; read_lock(&tasklist_lock); do_each_thread(g, p) { - if (!freezeable(p)) - continue; - - if (frozen(p)) + if (frozen(p) || !freezeable(p)) continue; if (p->state == TASK_TRACED && frozen(p->parent)) { cancel_freezing(p); continue; } - if (freeze_user_space && !is_user_space(p)) + + if (!freeze_task(p, freeze_user_space)) continue; - freeze_process(p); if (!freezer_should_skip(p)) todo++; } while_each_thread(g, p); read_unlock(&tasklist_lock); yield(); /* Yield is okay here */ - if (todo && time_after(jiffies, end_time)) + if (time_after(jiffies, end_time)) break; } while (todo); + do_gettimeofday(&end); + elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start); + do_div(elapsed_csecs64, NSEC_PER_SEC / 100); + elapsed_csecs = elapsed_csecs64; + if (todo) { /* This does not unfreeze processes that are already frozen * (we have slightly ugly calling convention in that respect, @@ -152,53 +211,49 @@ static unsigned int try_to_freeze_tasks(int freeze_user_space) * but it cleans up leftover PF_FREEZE requests. */ printk("\n"); - printk(KERN_ERR "Stopping %s timed out after %d seconds " + printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds " "(%d tasks refusing to freeze):\n", - freeze_user_space ? "user space processes" : - "kernel threads", - TIMEOUT / HZ, todo); + elapsed_csecs / 100, elapsed_csecs % 100, todo); + show_state(); read_lock(&tasklist_lock); do_each_thread(g, p) { - if (freeze_user_space && !is_user_space(p)) - continue; - task_lock(p); - if (freezeable(p) && !frozen(p) && - !freezer_should_skip(p)) + if (freezing(p) && !freezer_should_skip(p)) printk(KERN_ERR " %s\n", p->comm); - cancel_freezing(p); task_unlock(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); + } else { + printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100, + elapsed_csecs % 100); } - return todo; + return todo ? -EBUSY : 0; } /** * 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; + int error; + printk("Freezing user space processes ... "); + error = try_to_freeze_tasks(FREEZER_USER_SPACE); + if (error) + goto Exit; printk("done.\n"); + + printk("Freezing remaining freezable tasks ... "); + error = try_to_freeze_tasks(FREEZER_KERNEL_THREADS); + if (error) + goto Exit; + printk("done."); + Exit: BUG_ON(in_atomic()); - return 0; + printk("\n"); + return error; } static void thaw_tasks(int thaw_user_space) @@ -210,7 +265,7 @@ static void thaw_tasks(int thaw_user_space) if (!freezeable(p)) continue; - if (is_user_space(p) == !thaw_user_space) + if (!p->mm == thaw_user_space) continue; thaw_process(p);