#undef DEBUG
-#include <linux/smp_lock.h>
#include <linux/interrupt.h>
+#include <linux/oom.h>
#include <linux/suspend.h>
#include <linux/module.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
/*
* Timeout for stopping processes
*/
-#define TIMEOUT (6 * HZ)
-
+#define TIMEOUT (20 * HZ)
static inline int freezeable(struct task_struct * p)
{
- if ((p == current) ||
+ 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))
+ (p->exit_state != 0))
return 0;
return 1;
}
-/* 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;
- save = current->state;
- current->state = TASK_UNINTERRUPTIBLE;
- pr_debug("%s entered refrigerator\n", current->comm);
- printk("=");
-
- frozen_process(current);
- spin_lock_irq(¤t->sighand->siglock);
- recalc_sigpending(); /* We sent fake signal, clean it up */
- spin_unlock_irq(¤t->sighand->siglock);
-
- while (frozen(current))
- 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 int try_to_freeze_tasks(bool sig_only)
{
- int todo;
- unsigned long start_time;
struct task_struct *g, *p;
- unsigned long flags;
+ unsigned long end_time;
+ unsigned int todo;
+ struct timeval start, end;
+ u64 elapsed_csecs64;
+ unsigned int elapsed_csecs;
+
+ do_gettimeofday(&start);
- printk( "Stopping tasks: " );
- start_time = jiffies;
+ 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;
- freeze(p);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- signal_wake_up(p, 0);
- spin_unlock_irqrestore(&p->sighand->siglock, flags);
- todo++;
+ /*
+ * 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 (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 (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,
+ * and caller must call thaw_processes() if something fails),
+ * but it cleans up leftover PF_FREEZE requests.
+ */
+ printk("\n");
+ printk(KERN_ERR "Freezing of tasks failed after %d.%02d seconds "
+ "(%d tasks refusing to freeze):\n",
+ elapsed_csecs / 100, elapsed_csecs % 100, todo);
+ show_state();
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ task_lock(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 ? -EBUSY : 0;
+}
+
+/**
+ * freeze_processes - tell processes to enter the refrigerator
+ */
+int freeze_processes(void)
+{
+ 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.");
+
+ oom_killer_disable();
+ Exit:
BUG_ON(in_atomic());
- return 0;
+ printk("\n");
+
+ return error;
}
-void thaw_processes(void)
+static void thaw_tasks(bool nosig_only)
{
struct task_struct *g, *p;
- printk( "Restarting tasks..." );
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!freezeable(p))
continue;
- if (!thaw_process(p))
- printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
- } while_each_thread(g, p);
+ if (nosig_only && should_send_signal(p))
+ continue;
+
+ if (cgroup_frozen(p))
+ continue;
+
+ thaw_process(p);
+ } while_each_thread(g, p);
read_unlock(&tasklist_lock);
+}
+
+void thaw_processes(void)
+{
+ oom_killer_enable();
+
+ printk("Restarting tasks ... ");
+ thaw_tasks(true);
+ thaw_tasks(false);
schedule();
- printk( " done\n" );
+ printk("done.\n");
}
-EXPORT_SYMBOL(refrigerator);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff