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container freezer: make refrigerator always available 

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>
This commit is contained in:
Matt Helsley 2008-10-18 20:27:19 -07:00 committed by Linus Torvalds
parent 83224b0837
commit 8174f1503f
5 changed files with 137 additions and 119 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/linux/freezer.h
View 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 */

1
kernel/Makefile
View 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

122
kernel/freezer.c Normal file
View File

@ -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);
}
}

3
kernel/power/Kconfig
View 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

116
kernel/power/process.c
View 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);