*/
#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_tsk_thread_flag(current, TIF_FREEZE);
-}
-
-/* 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);
- current->state = save;
-}
-
-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_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(bool sig_only)
{
struct task_struct *g, *p;
unsigned long end_time;
unsigned int todo;
+ struct timeval start, end;
+ u64 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))
+ if (frozen(p) || !freezeable(p))
continue;
- if (frozen(p))
+ if (!freeze_task(p, sig_only))
continue;
- if (p->state == TASK_TRACED && frozen(p->parent)) {
- cancel_freezing(p);
- continue;
- }
- if (freeze_user_space && !is_user_space(p))
- continue;
-
- freeze_process(p);
- 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);
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,
* 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(true);
+ if (error)
+ goto Exit;
printk("done.\n");
+
+ printk("Freezing remaining freezable tasks ... ");
+ error = try_to_freeze_tasks(false);
+ 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)
+static void thaw_tasks(bool nosig_only)
{
struct task_struct *g, *p;
if (!freezeable(p))
continue;
- if (is_user_space(p) == !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