container freezer: make refrigerator always available
Matt Helsley [Sun, 19 Oct 2008 03:27:19 +0000 (20:27 -0700)]
Now that the TIF_FREEZE flag is available in all architectures, extract
the refrigerator() and freeze_task() from kernel/power/process.c and make
it available to all.

The refrigerator() can now be used in a control group subsystem
implementing a control group freezer.

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/freezer.h
kernel/Makefile
kernel/freezer.c [new file with mode: 0644]
kernel/power/Kconfig
kernel/power/process.c

index deddeed..17e3bb4 100644 (file)
@@ -6,7 +6,7 @@
 #include <linux/sched.h>
 #include <linux/wait.h>
 
-#ifdef CONFIG_PM_SLEEP
+#ifdef CONFIG_FREEZER
 /*
  * Check if a process has been frozen
  */
@@ -39,6 +39,11 @@ static inline void clear_freeze_flag(struct task_struct *p)
        clear_tsk_thread_flag(p, TIF_FREEZE);
 }
 
+static inline bool should_send_signal(struct task_struct *p)
+{
+       return !(p->flags & PF_FREEZER_NOSIG);
+}
+
 /*
  * Wake up a frozen process
  *
@@ -75,6 +80,9 @@ static inline int try_to_freeze(void)
                return 0;
 }
 
+extern bool freeze_task(struct task_struct *p, bool sig_only);
+extern void cancel_freezing(struct task_struct *p);
+
 /*
  * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
  * calls wait_for_completion(&vfork) and reset right after it returns from this
@@ -166,7 +174,7 @@ static inline void set_freezable_with_signal(void)
        } while (try_to_freeze());                                      \
        __retval;                                                       \
 })
-#else /* !CONFIG_PM_SLEEP */
+#else /* !CONFIG_FREEZER */
 static inline int frozen(struct task_struct *p) { return 0; }
 static inline int freezing(struct task_struct *p) { return 0; }
 static inline void set_freeze_flag(struct task_struct *p) {}
@@ -191,6 +199,6 @@ static inline void set_freezable_with_signal(void) {}
 #define wait_event_freezable_timeout(wq, condition, timeout)           \
                wait_event_interruptible_timeout(wq, condition, timeout)
 
-#endif /* !CONFIG_PM_SLEEP */
+#endif /* !CONFIG_FREEZER */
 
 #endif /* FREEZER_H_INCLUDED */
index 4e1d7df..e8194d1 100644 (file)
@@ -24,6 +24,7 @@ CFLAGS_REMOVE_sched_clock.o = -pg
 CFLAGS_REMOVE_sched.o = -mno-spe -pg
 endif
 
+obj-$(CONFIG_FREEZER) += freezer.o
 obj-$(CONFIG_PROFILING) += profile.o
 obj-$(CONFIG_SYSCTL_SYSCALL_CHECK) += sysctl_check.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/kernel/freezer.c b/kernel/freezer.c
new file mode 100644 (file)
index 0000000..cb0931f
--- /dev/null
@@ -0,0 +1,122 @@
+/*
+ * kernel/freezer.c - Function to freeze a process
+ *
+ * Originally from kernel/power/process.c
+ */
+
+#include <linux/interrupt.h>
+#include <linux/suspend.h>
+#include <linux/module.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
+
+/*
+ * 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(&current->sighand->siglock);
+       recalc_sigpending(); /* We sent fake signal, clean it up */
+       spin_unlock_irq(&current->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);
+}
+EXPORT_SYMBOL(refrigerator);
+
+static void fake_signal_wake_up(struct task_struct *p)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&p->sighand->siglock, flags);
+       signal_wake_up(p, 0);
+       spin_unlock_irqrestore(&p->sighand->siglock, flags);
+}
+
+/**
+ *     freeze_task - send a freeze request to given task
+ *     @p: task to send the request to
+ *     @sig_only: if set, the request will only be sent if the task has the
+ *             PF_FREEZER_NOSIG flag unset
+ *     Return value: 'false', if @sig_only is set and the task has
+ *             PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
+ *
+ *     The freeze request is sent by setting 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 PF_FREEZER_NOSIG set.  If @sig_only is set and the task
+ *     has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
+ *     TIF_FREEZE flag will not be set.
+ */
+bool freeze_task(struct task_struct *p, bool sig_only)
+{
+       /*
+        * We first check if the task is freezing and next if it has already
+        * been frozen to avoid the race with frozen_process() which first marks
+        * the task as frozen and next clears its TIF_FREEZE.
+        */
+       if (!freezing(p)) {
+               rmb();
+               if (frozen(p))
+                       return false;
+
+               if (!sig_only || should_send_signal(p))
+                       set_freeze_flag(p);
+               else
+                       return false;
+       }
+
+       if (should_send_signal(p)) {
+               if (!signal_pending(p))
+                       fake_signal_wake_up(p);
+       } else if (sig_only) {
+               return false;
+       } else {
+               wake_up_state(p, TASK_INTERRUPTIBLE);
+       }
+
+       return true;
+}
+
+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);
+       }
+}
index dcd165f..ebdd7f5 100644 (file)
@@ -85,6 +85,9 @@ config PM_SLEEP
        depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
        default y
 
+config FREEZER
+       def_bool PM_SLEEP
+
 config SUSPEND
        bool "Suspend to RAM and standby"
        depends on PM && ARCH_SUSPEND_POSSIBLE
index 278946a..444cea8 100644 (file)
@@ -28,121 +28,6 @@ static inline int freezeable(struct task_struct * p)
        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(&current->sighand->siglock);
-       recalc_sigpending(); /* We sent fake signal, clean it up */
-       spin_unlock_irq(&current->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)
-{
-       unsigned long flags;
-
-       spin_lock_irqsave(&p->sighand->siglock, flags);
-       signal_wake_up(p, 0);
-       spin_unlock_irqrestore(&p->sighand->siglock, flags);
-}
-
-static inline bool should_send_signal(struct task_struct *p)
-{
-       return !(p->flags & PF_FREEZER_NOSIG);
-}
-
-/**
- *     freeze_task - send a freeze request to given task
- *     @p: task to send the request to
- *     @sig_only: if set, the request will only be sent if the task has the
- *             PF_FREEZER_NOSIG flag unset
- *     Return value: 'false', if @sig_only is set and the task has
- *             PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
- *
- *     The freeze request is sent by setting 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 PF_FREEZER_NOSIG set.  If @sig_only is set and the task
- *     has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
- *     TIF_FREEZE flag will not be set.
- */
-static bool freeze_task(struct task_struct *p, bool sig_only)
-{
-       /*
-        * We first check if the task is freezing and next if it has already
-        * been frozen to avoid the race with frozen_process() which first marks
-        * the task as frozen and next clears its TIF_FREEZE.
-        */
-       if (!freezing(p)) {
-               rmb();
-               if (frozen(p))
-                       return false;
-
-               if (!sig_only || should_send_signal(p))
-                       set_freeze_flag(p);
-               else
-                       return false;
-       }
-
-       if (should_send_signal(p)) {
-               if (!signal_pending(p))
-                       fake_signal_wake_up(p);
-       } else if (sig_only) {
-               return false;
-       } else {
-               wake_up_state(p, TASK_INTERRUPTIBLE);
-       }
-
-       return true;
-}
-
-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(bool sig_only)
 {
        struct task_struct *g, *p;
@@ -264,4 +149,3 @@ void thaw_processes(void)
        printk("done.\n");
 }
 
-EXPORT_SYMBOL(refrigerator);