Re: [PATCH -mm 3/3] PM: Introduce suspend notifiers (rev. 2)
From: Rafael J. Wysocki
Date: Tue Apr 24 2007 - 07:22:32 EST
On Tuesday, 24 April 2007 12:28, Andrew Morton wrote:
> On Sun, 22 Apr 2007 20:48:08 +0200 "Rafael J. Wysocki" <rjw@xxxxxxx> wrote:
>
> > Make it possible to register suspend notifiers so that subsystems can perform
> > suspend-related operations that should not be carried out by device drivers'
> > .suspend() and .resume() routines.
>
> x86_64 allnoconfig:
>
> arch/x86_64/kernel/e820.c: In function 'e820_mark_nosave_regions':
> arch/x86_64/kernel/e820.c:279: warning: implicit declaration of function 'register_nosave_region'
> arch/x86_64/kernel/built-in.o: In function `e820_mark_nosave_regions':
> : undefined reference to `register_nosave_region'
> arch/x86_64/kernel/built-in.o: In function `e820_mark_nosave_regions':
> : undefined reference to `register_nosave_region'
Ouch, I tried to be too smart. Fixed.
---
From: Rafael J. Wysocki <rjw@xxxxxxx>
Make it possible to register suspend notifiers so that subsystems can perform
suspend-related operations that should not be carried out by device drivers'
.suspend() and .resume() routines.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
Documentation/power/suspend-notifiers.txt | 48 ++++++++++++++++++++++++++++
include/linux/notifier.h | 6 +++
include/linux/suspend.h | 19 +++++++++++
kernel/power/Makefile | 2 -
kernel/power/disk.c | 23 ++++++++++++-
kernel/power/main.c | 16 ++++++++-
kernel/power/notify.c | 51 ++++++++++++++++++++++++++++++
kernel/power/power.h | 3 +
kernel/power/user.c | 45 ++++++++++++++++++++------
9 files changed, 199 insertions(+), 14 deletions(-)
Index: linux-2.6.21-rc6-mm1/kernel/power/notify.c
===================================================================
--- /dev/null
+++ linux-2.6.21-rc6-mm1/kernel/power/notify.c
@@ -0,0 +1,51 @@
+/*
+ * linux/kernel/power/notify.c
+ *
+ * This file contains functions used for registering and calling suspend
+ * notifiers that can be used by subsystems for carrying out some special
+ * suspend-related operations.
+ *
+ * Copyright (C) 2007 Rafael J. Wysocki <rjw@xxxxxxx>
+ *
+ * This file is released under the GPLv2.
+ *
+ */
+
+#include <linux/smp.h>
+#include <linux/notifier.h>
+#include <linux/module.h>
+#include <linux/suspend.h>
+
+static DEFINE_MUTEX(suspend_notifier_lock);
+
+static RAW_NOTIFIER_HEAD(suspend_chain);
+
+int register_suspend_notifier(struct notifier_block *nb)
+{
+ int ret;
+ mutex_lock(&suspend_notifier_lock);
+ ret = raw_notifier_chain_register(&suspend_chain, nb);
+ mutex_unlock(&suspend_notifier_lock);
+ return ret;
+}
+EXPORT_SYMBOL(register_suspend_notifier);
+
+void unregister_suspend_notifier(struct notifier_block *nb)
+{
+ mutex_lock(&suspend_notifier_lock);
+ raw_notifier_chain_unregister(&suspend_chain, nb);
+ mutex_unlock(&suspend_notifier_lock);
+}
+EXPORT_SYMBOL(unregister_suspend_notifier);
+
+int suspend_notifier_call_chain(unsigned long val)
+{
+ int error = 0;
+
+ mutex_lock(&suspend_notifier_lock);
+ if (raw_notifier_call_chain(&suspend_chain, val, NULL) == NOTIFY_BAD)
+ error = -EINVAL;
+
+ mutex_unlock(&suspend_notifier_lock);
+ return error;
+}
Index: linux-2.6.21-rc6-mm1/include/linux/suspend.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/linux/suspend.h
+++ linux-2.6.21-rc6-mm1/include/linux/suspend.h
@@ -60,4 +60,23 @@ struct saved_context;
void __save_processor_state(struct saved_context *ctxt);
void __restore_processor_state(struct saved_context *ctxt);
+#ifdef CONFIG_PM
+int register_suspend_notifier(struct notifier_block *nb);
+void unregister_suspend_notifier(struct notifier_block *nb);
+
+#define suspend_notifier(fn, pri) { \
+ static struct notifier_block fn##_nb = \
+ { .notifier_call = fn, .priority = pri }; \
+ register_suspend_notifier(&fn##_nb); \
+}
+#else /* CONFIG_PM */
+static inline int register_suspend_notifier(struct notifier_block *nb) {
+ return 0;
+}
+static inline void unregister_suspend_notifier(struct notifier_block *nb) {
+}
+
+#define suspend_notifier(fn, pri) do { (void)(fn); } while (0)
+#endif /* CONFIG_PM */
+
#endif /* _LINUX_SWSUSP_H */
Index: linux-2.6.21-rc6-mm1/kernel/power/Makefile
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/power/Makefile
+++ linux-2.6.21-rc6-mm1/kernel/power/Makefile
@@ -3,7 +3,7 @@ ifeq ($(CONFIG_PM_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
endif
-obj-y := main.o process.o console.o
+obj-y := main.o process.o console.o notify.o
obj-$(CONFIG_PM_LEGACY) += pm.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o user.o
Index: linux-2.6.21-rc6-mm1/kernel/power/power.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/power/power.h
+++ linux-2.6.21-rc6-mm1/kernel/power/power.h
@@ -170,3 +170,6 @@ extern int suspend_enter(suspend_state_t
struct timeval;
extern void swsusp_show_speed(struct timeval *, struct timeval *,
unsigned int, char *);
+
+/* kernel/power/notify.c */
+extern int suspend_notifier_call_chain(unsigned long val);
Index: linux-2.6.21-rc6-mm1/include/linux/notifier.h
===================================================================
--- linux-2.6.21-rc6-mm1.orig/include/linux/notifier.h
+++ linux-2.6.21-rc6-mm1/include/linux/notifier.h
@@ -209,5 +209,11 @@ extern int __srcu_notifier_call_chain(st
#define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
+#define SUSPEND_PREPARE 0x0002 /* Going to freeze tasks */
+#define SUSPEND_ENTER_PREPARE 0x0003 /* Tasks are frozen, we are suspending */
+#define SUSPEND_THAW_PREPARE 0x0004 /* Going to thaw frozen tasks */
+#define SUSPEND_FINISHED 0x0005 /* Tasks have been thawed */
+#define SUSPEND_RESTORE_PREPARE 0x0006 /* STD restore is going to happen */
+
#endif /* __KERNEL__ */
#endif /* _LINUX_NOTIFIER_H */
Index: linux-2.6.21-rc6-mm1/kernel/power/disk.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/power/disk.c
+++ linux-2.6.21-rc6-mm1/kernel/power/disk.c
@@ -139,10 +139,18 @@ int pm_suspend_disk(void)
if (error)
goto Exit;
+ error = suspend_notifier_call_chain(SUSPEND_PREPARE);
+ if (error)
+ goto Finish;
+
error = prepare_processes();
if (error)
goto Finish;
+ error = suspend_notifier_call_chain(SUSPEND_ENTER_PREPARE);
+ if (error)
+ goto Thaw;
+
if (pm_disk_mode == PM_DISK_TESTPROC) {
printk("swsusp debug: Waiting for 5 seconds.\n");
mdelay(5000);
@@ -205,8 +213,10 @@ int pm_suspend_disk(void)
device_resume();
resume_console();
Thaw:
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
unprepare_processes();
Finish:
+ suspend_notifier_call_chain(SUSPEND_FINISHED);
free_basic_memory_bitmaps();
Exit:
atomic_inc(&snapshot_device_available);
@@ -267,6 +277,10 @@ static int software_resume(void)
if (error)
goto Finish;
+ error = suspend_notifier_call_chain(SUSPEND_PREPARE);
+ if (error)
+ goto Done;
+
pr_debug("PM: Preparing processes for restore.\n");
error = prepare_processes();
if (error) {
@@ -279,9 +293,13 @@ static int software_resume(void)
error = swsusp_read();
if (error) {
swsusp_free();
- goto Thaw;
+ goto Unprepare;
}
+ error = suspend_notifier_call_chain(SUSPEND_RESTORE_PREPARE);
+ if (error)
+ goto Thaw;
+
pr_debug("PM: Preparing devices for restore.\n");
suspend_console();
@@ -299,9 +317,12 @@ static int software_resume(void)
device_resume();
resume_console();
Thaw:
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
+ Unprepare:
printk(KERN_ERR "PM: Restore failed, recovering.\n");
unprepare_processes();
Done:
+ suspend_notifier_call_chain(SUSPEND_FINISHED);
free_basic_memory_bitmaps();
Finish:
atomic_inc(&snapshot_device_available);
Index: linux-2.6.21-rc6-mm1/kernel/power/main.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/power/main.c
+++ linux-2.6.21-rc6-mm1/kernel/power/main.c
@@ -86,11 +86,20 @@ static int suspend_prepare(suspend_state
pm_prepare_console();
+ error = suspend_notifier_call_chain(SUSPEND_PREPARE);
+ if (error)
+ goto Finish;
+
if (freeze_processes()) {
error = -EAGAIN;
- goto Thaw;
+ thaw_processes();
+ goto Finish;
}
+ error = suspend_notifier_call_chain(SUSPEND_ENTER_PREPARE);
+ if (error)
+ goto Thaw;
+
if ((free_pages = global_page_state(NR_FREE_PAGES))
< FREE_PAGE_NUMBER) {
pr_debug("PM: free some memory\n");
@@ -123,8 +132,11 @@ static int suspend_prepare(suspend_state
device_resume();
resume_console();
Thaw:
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
thaw_processes();
+ Finish:
pm_restore_console();
+ suspend_notifier_call_chain(SUSPEND_FINISHED);
return error;
}
@@ -162,8 +174,10 @@ static void suspend_finish(suspend_state
pm_finish(state);
device_resume();
resume_console();
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
thaw_processes();
pm_restore_console();
+ suspend_notifier_call_chain(SUSPEND_FINISHED);
}
Index: linux-2.6.21-rc6-mm1/kernel/power/user.c
===================================================================
--- linux-2.6.21-rc6-mm1.orig/kernel/power/user.c
+++ linux-2.6.21-rc6-mm1/kernel/power/user.c
@@ -75,6 +75,18 @@ static int snapshot_open(struct inode *i
return 0;
}
+static void snapshot_unfreeze(struct snapshot_data *data)
+{
+ if (!data->frozen)
+ return;
+
+ mutex_lock(&pm_mutex);
+ thaw_processes();
+ suspend_notifier_call_chain(SUSPEND_FINISHED);
+ mutex_unlock(&pm_mutex);
+ data->frozen = 0;
+}
+
static int snapshot_release(struct inode *inode, struct file *filp)
{
struct snapshot_data *data;
@@ -83,11 +95,7 @@ static int snapshot_release(struct inode
free_basic_memory_bitmaps();
data = filp->private_data;
free_all_swap_pages(data->swap);
- if (data->frozen) {
- mutex_lock(&pm_mutex);
- thaw_processes();
- mutex_unlock(&pm_mutex);
- }
+ snapshot_unfreeze(data);
atomic_inc(&snapshot_device_available);
return 0;
}
@@ -147,6 +155,10 @@ static inline int snapshot_suspend(int p
int error;
mutex_lock(&pm_mutex);
+ error = suspend_notifier_call_chain(SUSPEND_ENTER_PREPARE);
+ if (error)
+ goto Finish;
+
/* Free memory before shutting down devices. */
error = swsusp_shrink_memory();
if (error)
@@ -175,6 +187,7 @@ static inline int snapshot_suspend(int p
device_resume();
resume_console();
Finish:
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
mutex_unlock(&pm_mutex);
return error;
}
@@ -185,6 +198,10 @@ static inline int snapshot_restore(int p
mutex_lock(&pm_mutex);
pm_prepare_console();
+ error = suspend_notifier_call_chain(SUSPEND_RESTORE_PREPARE);
+ if (error)
+ goto Finish;
+
if (platform_suspend) {
error = platform_prepare();
if (error)
@@ -207,6 +224,7 @@ static inline int snapshot_restore(int p
device_resume();
resume_console();
Finish:
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
pm_restore_console();
mutex_unlock(&pm_mutex);
return error;
@@ -235,8 +253,13 @@ static int snapshot_ioctl(struct inode *
if (data->frozen)
break;
mutex_lock(&pm_mutex);
+ error = suspend_notifier_call_chain(SUSPEND_PREPARE);
+ if (error)
+ break;
+
if (freeze_processes()) {
thaw_processes();
+ suspend_notifier_call_chain(SUSPEND_FINISHED);
error = -EBUSY;
}
mutex_unlock(&pm_mutex);
@@ -245,12 +268,7 @@ static int snapshot_ioctl(struct inode *
break;
case SNAPSHOT_UNFREEZE:
- if (!data->frozen)
- break;
- mutex_lock(&pm_mutex);
- thaw_processes();
- mutex_unlock(&pm_mutex);
- data->frozen = 0;
+ snapshot_unfreeze(data);
break;
case SNAPSHOT_ATOMIC_SNAPSHOT:
@@ -349,6 +367,10 @@ static int snapshot_ioctl(struct inode *
break;
}
+ error = suspend_notifier_call_chain(SUSPEND_ENTER_PREPARE);
+ if (error)
+ goto OutS3;
+
if (pm_ops->prepare) {
error = pm_ops->prepare(PM_SUSPEND_MEM);
if (error)
@@ -375,6 +397,7 @@ static int snapshot_ioctl(struct inode *
pm_ops->finish(PM_SUSPEND_MEM);
OutS3:
+ suspend_notifier_call_chain(SUSPEND_THAW_PREPARE);
mutex_unlock(&pm_mutex);
break;
Index: linux-2.6.21-rc6-mm1/Documentation/power/suspend-notifiers.txt
===================================================================
--- /dev/null
+++ linux-2.6.21-rc6-mm1/Documentation/power/suspend-notifiers.txt
@@ -0,0 +1,48 @@
+Suspend notifiers
+ (C) 2007 Rafael J. Wysocki <rjw@xxxxxxx>, GPL
+
+There are some operations that device drivers may want to carry out in their
+.suspend() routines, but shouldn't, because they can cause a suspend to fail.
+For example, a driver may want to allocate a substantial amount of memory
+(like 50 MB) in .suspend(), but that shouldn't be done after the swsusp's memory
+shrinker has run. Also, there may be some operations, that subsystems may want
+to carry out before a suspend or after a resume, requiring the system to be
+fully functional, so the drivers' .suspend() and .resume() routines are not
+suitable for this purpose.
+
+The subsystems that have such needs can register suspend notifiers that will be
+notified of the following events by the suspend core:
+
+SUSPEND_PREPARE the system is going to suspend, tasks will be frozen
+ immediately
+
+SUSPEND_ENTER_PREPARE tasks have been frozen, memory is going to be freed
+ and devices are going to be suspended
+
+SUSPEND_THAW_PREPARE devices have been resumed, tasks will be thawed
+ immediately
+
+SUSPEND_FINISHED the resume is complete, the system is fully functional
+
+SUSPEND_RESTORE_PREPARE the system is preparing to restore the swsusp's suspend
+ image, tasks have been frozen and devices are going to
+ be suspended
+
+It is generally assumed that whatever the notifiers do for SUSPEND_PREPARE,
+should be undone for SUSPEND_FINISHED, and what is done for
+SUSPEND_ENTER_PREPARE, should be undone for SUSPEND_FINISHED (eg. if memory is
+allocated for SUSPEND_ENTER_PREPARE, it should be freed for SUSPEND_FINISHED).
+Moreover, if the SUSPEND_PREPARE hooks are called, SUSPEND_FINISHED will be
+called too and if SUSPEND_ENTER_PREPARE are called, SUSPEND_THAW_PREPARE will be
+called either, even if the suspend fails. This way, for example, the memory
+allocated with SUSPEND_ENTER_PREPARE can always be freed with
+SUSPEND_THAW_PREPARE and need not be leaked in case the suspend fails.
+
+The suspend notifiers are called with pm_mutex held.
+
+The suspend notifiers are defined in the usual way, but their last argument is
+meaningless (it is always NULL). To register and/or unregister a suspend
+notifier use the functions register_suspend_notifier() and
+unregister_suspend_notifier(), respectively, defined in kernel/power/notify.c .
+If you don't need to unregister the notifier, you can also use the
+suspend_notifier() macro defined in include/linux/suspend.h .
-
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