*/
#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) ||
return 1;
}
-/*
- * freezing is complete, mark current process as frozen
- */
-static inline void frozen_process(void)
-{
- if (!unlikely(current->flags & PF_NOFREEZE)) {
- current->flags |= PF_FROZEN;
- wmb();
- }
- clear_freeze_flag(current);
-}
-
-/* Refrigerator is place where frozen processes are stored :-). */
-void refrigerator(void)
-{
- /* Hmm, should we be allowed to suspend when there are realtime
- processes around? */
- long save;
-
- task_lock(current);
- if (freezing(current)) {
- frozen_process();
- task_unlock(current);
- } else {
- task_unlock(current);
- return;
- }
- save = current->state;
- pr_debug("%s entered refrigerator\n", current->comm);
-
- spin_lock_irq(¤t->sighand->siglock);
- recalc_sigpending(); /* We sent fake signal, clean it up */
- spin_unlock_irq(¤t->sighand->siglock);
-
- for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!frozen(current))
- break;
- schedule();
- }
- pr_debug("%s left refrigerator\n", current->comm);
- __set_current_state(save);
-}
-
-static void fake_signal_wake_up(struct task_struct *p, int resume)
-{
- unsigned long flags;
-
- 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 (task_is_stopped(p))
- force_sig_specific(SIGSTOP, p);
- fake_signal_wake_up(p, task_is_stopped(p));
-}
-
-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)) {
- 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)
-{
- unsigned long flags;
-
- if (freezing(p)) {
- pr_debug(" clean up: %s\n", p->comm);
- clear_freeze_flag(p);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- recalc_sigpending_and_wake(p);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- }
-}
-
-static int try_to_freeze_tasks(int freeze_user_space)
+static int try_to_freeze_tasks(bool sig_only)
{
struct task_struct *g, *p;
unsigned long end_time;
unsigned int todo;
struct timeval start, end;
- s64 elapsed_csecs64;
+ u64 elapsed_csecs64;
unsigned int elapsed_csecs;
do_gettimeofday(&start);
if (frozen(p) || !freezeable(p))
continue;
- if (task_is_traced(p) && frozen(p->parent)) {
- cancel_freezing(p);
- continue;
- }
-
- if (!freeze_task(p, freeze_user_space))
+ if (!freeze_task(p, sig_only))
continue;
- if (!freezer_should_skip(p))
+ /*
+ * Now that we've done set_freeze_flag, don't
+ * perturb a task in TASK_STOPPED or TASK_TRACED.
+ * It is "frozen enough". If the task does wake
+ * up, it will immediately call try_to_freeze.
+ */
+ if (!task_is_stopped_or_traced(p) &&
+ !freezer_should_skip(p))
todo++;
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
int error;
printk("Freezing user space processes ... ");
- error = try_to_freeze_tasks(FREEZER_USER_SPACE);
+ error = try_to_freeze_tasks(true);
if (error)
goto Exit;
printk("done.\n");
printk("Freezing remaining freezable tasks ... ");
- error = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
+ error = try_to_freeze_tasks(false);
if (error)
goto Exit;
printk("done.");
return error;
}
-static void thaw_tasks(int thaw_user_space)
+static void thaw_tasks(bool nosig_only)
{
struct task_struct *g, *p;
if (!freezeable(p))
continue;
- if (!p->mm == thaw_user_space)
+ if (nosig_only && should_send_signal(p))
+ continue;
+
+ if (cgroup_frozen(p))
continue;
thaw_process(p);
void thaw_processes(void)
{
printk("Restarting tasks ... ");
- thaw_tasks(FREEZER_KERNEL_THREADS);
- thaw_tasks(FREEZER_USER_SPACE);
+ thaw_tasks(true);
+ thaw_tasks(false);
schedule();
printk("done.\n");
}
-EXPORT_SYMBOL(refrigerator);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff