#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>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
/*
* Timeout for stopping processes
*/
#define TIMEOUT (20 * HZ)
-
-static inline int freezeable(struct task_struct * p)
+static inline int freezable(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->exit_state != 0))
return 0;
return 1;
}
-/* Refrigerator is place where frozen processes are stored :-). */
-void refrigerator(void)
+static int try_to_freeze_tasks(bool sig_only)
{
- /* Hmm, should we be allowed to suspend when there are realtime
- processes around? */
- long save;
- save = current->state;
- pr_debug("%s entered refrigerator\n", current->comm);
-
- 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)) {
- current->state = TASK_UNINTERRUPTIBLE;
- schedule();
- }
- pr_debug("%s left refrigerator\n", current->comm);
- current->state = save;
-}
+ struct task_struct *g, *p;
+ unsigned long end_time;
+ unsigned int todo;
+ bool wq_busy = false;
+ struct timeval start, end;
+ u64 elapsed_csecs64;
+ unsigned int elapsed_csecs;
+ bool wakeup = false;
-static inline void freeze_process(struct task_struct *p)
-{
- unsigned long flags;
+ do_gettimeofday(&start);
- if (!freezing(p)) {
- freeze(p);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- signal_wake_up(p, 0);
- 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);
- }
-}
+ end_time = jiffies + TIMEOUT;
-/* 0 = success, else # of processes that we failed to stop */
-int freeze_processes(void)
-{
- int todo, nr_user, user_frozen;
- unsigned long start_time;
- struct task_struct *g, *p;
+ if (!sig_only)
+ freeze_workqueues_begin();
- printk( "Stopping tasks: " );
- start_time = jiffies;
- user_frozen = 0;
- do {
- nr_user = todo = 0;
+ while (true) {
+ todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
- if (!freezeable(p))
+ if (frozen(p) || !freezable(p))
continue;
- if (frozen(p))
- continue;
- if (p->state == TASK_TRACED && frozen(p->parent)) {
- cancel_freezing(p);
+
+ if (!freeze_task(p, sig_only))
continue;
- }
- if (p->mm && !(p->flags & PF_BORROWED_MM)) {
- /* The task is a user-space one.
- * Freeze it unless there's a vfork completion
- * pending
- */
- if (!p->vfork_done)
- freeze_process(p);
- nr_user++;
- } else {
- /* Freeze only if the user space is frozen */
- if (user_frozen)
- freeze_process(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.
+ *
+ * Because freeze_task() goes through p's
+ * scheduler lock after setting TIF_FREEZE, it's
+ * guaranteed that either we see TASK_RUNNING or
+ * try_to_stop() after schedule() in ptrace/signal
+ * stop sees TIF_FREEZE.
+ */
+ if (!task_is_stopped_or_traced(p) &&
+ !freezer_should_skip(p))
todo++;
- }
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
- todo += nr_user;
- if (!user_frozen && !nr_user) {
- sys_sync();
- start_time = jiffies;
+
+ if (!sig_only) {
+ wq_busy = freeze_workqueues_busy();
+ todo += wq_busy;
}
- user_frozen = !nr_user;
- yield(); /* Yield is okay here */
- if (todo && time_after(jiffies, start_time + TIMEOUT))
+
+ if (!todo || time_after(jiffies, end_time))
break;
- } while(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.
- */
+ if (pm_wakeup_pending()) {
+ wakeup = true;
+ break;
+ }
+
+ /*
+ * We need to retry, but first give the freezing tasks some
+ * time to enter the regrigerator.
+ */
+ msleep(10);
+ }
+
+ 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) {
- printk( "\n" );
- printk(KERN_ERR " stopping tasks timed out "
- "after %d seconds (%d tasks remaining):\n",
- TIMEOUT / HZ, 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 %s after %d.%02d seconds "
+ "(%d tasks refusing to freeze, wq_busy=%d):\n",
+ wakeup ? "aborted" : "failed",
+ elapsed_csecs / 100, elapsed_csecs % 100,
+ todo - wq_busy, wq_busy);
+
+ thaw_workqueues();
+
read_lock(&tasklist_lock);
do_each_thread(g, p) {
- if (freezeable(p) && !frozen(p))
- printk(KERN_ERR " %s\n", p->comm);
+ task_lock(p);
+ if (!wakeup && freezing(p) && !freezer_should_skip(p))
+ sched_show_task(p);
cancel_freezing(p);
+ task_unlock(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
- return todo;
+ } else {
+ printk("(elapsed %d.%02d seconds) ", elapsed_csecs / 100,
+ elapsed_csecs % 100);
}
- printk( "|\n" );
+ 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))
+ if (!freezable(p))
+ continue;
+
+ if (nosig_only && should_send_signal(p))
continue;
- if (!thaw_process(p))
- printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
- } while_each_thread(g, p);
+ if (cgroup_freezing_or_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_workqueues();
+ thaw_tasks(true);
+ thaw_tasks(false);
schedule();
- printk( " done\n" );
+ printk("done.\n");
}
-EXPORT_SYMBOL(refrigerator);
Code Review / linux-2.6.git / blobdiff