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Message-Id: <200704281137.23195.rjw@sisk.pl>
Date: Sat, 28 Apr 2007 11:37:22 +0200
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Gautham R Shenoy <ego@...ibm.com>, Ingo Molnar <mingo@...e.hu>,
Oleg Nesterov <oleg@...sign.ru>, Pavel Machek <pavel@....cz>,
Pekka Enberg <penberg@...helsinki.fi>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH -mm 1/2] Separate freezer from PM code (rev. 2)
From: Rafael J. Wysocki <rjw@...k.pl>
Now that the freezer is used by kprobes, it is no longer a PM-specific piece of
code. Move the freezer code out of kernel/power and introduce the
CONFIG_FREEZER option that will be chosen automatically if PM or KPROBES is
set.
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
---
arch/arm/Kconfig | 2
arch/avr32/Kconfig | 2
arch/avr32/Kconfig.debug | 1
arch/blackfin/Kconfig | 2
arch/frv/Kconfig | 2
arch/i386/Kconfig | 3
arch/ia64/Kconfig | 3
arch/mips/Kconfig | 2
arch/powerpc/Kconfig | 3
arch/ppc/Kconfig | 2
arch/s390/Kconfig | 3
arch/sh/Kconfig | 2
arch/sparc64/Kconfig | 3
arch/x86_64/Kconfig | 3
include/linux/freezer.h | 2
kernel/Kconfig.freezer | 5
kernel/Makefile | 1
kernel/freezer.c | 236 +++++++++++++++++++++++++++++++++++++++++++++++
kernel/kprobes.c | 2
kernel/power/Kconfig | 1
kernel/power/Makefile | 2
kernel/power/process.c | 236 -----------------------------------------------
22 files changed, 279 insertions(+), 239 deletions(-)
Index: linux-2.6.21-rc7-mm2/arch/x86_64/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/x86_64/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/x86_64/Kconfig 2007-04-27 23:20:43.000000000 +0200
@@ -703,6 +703,8 @@ config GENERIC_PENDING_IRQ
depends on GENERIC_HARDIRQS && SMP
default y
+source "kernel/Kconfig.freezer"
+
menu "Power management options"
source kernel/power/Kconfig
@@ -791,6 +793,7 @@ source "arch/x86_64/oprofile/Kconfig"
config KPROBES
bool "Kprobes (EXPERIMENTAL)"
depends on KALLSYMS && EXPERIMENTAL && MODULES
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/arch/avr32/Kconfig.debug
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/avr32/Kconfig.debug 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/avr32/Kconfig.debug 2007-04-27 21:54:19.000000000 +0200
@@ -12,6 +12,7 @@ menu "Instrumentation Support"
config KPROBES
bool "Kprobes"
depends on DEBUG_KERNEL
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/arch/frv/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/frv/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/frv/Kconfig 2007-04-27 23:13:27.000000000 +0200
@@ -364,6 +364,8 @@ source "drivers/pcmcia/Kconfig"
# sleep-deprived psychotic hacker types can say Y now, everyone else
# should probably wait a while.
+source "kernel/Kconfig.freezer"
+
menu "Power management options"
source kernel/power/Kconfig
endmenu
Index: linux-2.6.21-rc7-mm2/arch/i386/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/i386/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/i386/Kconfig 2007-04-27 23:17:36.000000000 +0200
@@ -912,6 +912,8 @@ config ARCH_ENABLE_MEMORY_HOTPLUG
def_bool y
depends on HIGHMEM
+source "kernel/Kconfig.freezer"
+
menu "Power management options (ACPI, APM)"
depends on !X86_VOYAGER
@@ -1218,6 +1220,7 @@ source "arch/i386/oprofile/Kconfig"
config KPROBES
bool "Kprobes (EXPERIMENTAL)"
depends on KALLSYMS && EXPERIMENTAL && MODULES
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/arch/ia64/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/ia64/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/ia64/Kconfig 2007-04-27 23:21:40.000000000 +0200
@@ -495,6 +495,8 @@ source "fs/Kconfig.binfmt"
endmenu
+source "kernel/Kconfig.freezer"
+
menu "Power management and ACPI"
source "kernel/power/Kconfig"
@@ -582,6 +584,7 @@ source "arch/ia64/oprofile/Kconfig"
config KPROBES
bool "Kprobes (EXPERIMENTAL)"
depends on KALLSYMS && EXPERIMENTAL && MODULES
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/arch/powerpc/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/powerpc/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/powerpc/Kconfig 2007-04-27 23:15:12.000000000 +0200
@@ -552,6 +552,8 @@ config CMDLINE
some command-line options at build time by entering them here. In
most cases you will need to specify the root device here.
+source kernel/Kconfig.freezer
+
if !44x || BROKEN
source kernel/power/Kconfig
endif
@@ -865,6 +867,7 @@ source "arch/powerpc/oprofile/Kconfig"
config KPROBES
bool "Kprobes (EXPERIMENTAL)"
depends on !BOOKE && !4xx && KALLSYMS && EXPERIMENTAL && MODULES
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/arch/ppc/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/ppc/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/ppc/Kconfig 2007-04-27 23:15:25.000000000 +0200
@@ -1153,6 +1153,8 @@ config PROC_HARDWARE
source "drivers/zorro/Kconfig"
+source "kernel/Kconfig.freezer"
+
if !44x || BROKEN
source kernel/power/Kconfig
endif
Index: linux-2.6.21-rc7-mm2/arch/s390/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/s390/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/s390/Kconfig 2007-04-27 23:23:19.000000000 +0200
@@ -550,6 +550,8 @@ source "drivers/net/Kconfig"
source "fs/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Instrumentation Support"
source "arch/s390/oprofile/Kconfig"
@@ -557,6 +559,7 @@ source "arch/s390/oprofile/Kconfig"
config KPROBES
bool "Kprobes (EXPERIMENTAL)"
depends on EXPERIMENTAL && MODULES
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/arch/sh/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/sh/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/sh/Kconfig 2007-04-27 23:23:33.000000000 +0200
@@ -699,6 +699,8 @@ source "fs/Kconfig.binfmt"
endmenu
+source "kernel/Kconfig.freezer"
+
menu "Power management options (EXPERIMENTAL)"
depends on EXPERIMENTAL
Index: linux-2.6.21-rc7-mm2/arch/sparc64/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/sparc64/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/sparc64/Kconfig 2007-04-27 23:23:44.000000000 +0200
@@ -420,6 +420,8 @@ source "drivers/fc4/Kconfig"
source "fs/Kconfig"
+source "kernel/Kconfig.freezer"
+
menu "Instrumentation Support"
depends on EXPERIMENTAL
@@ -428,6 +430,7 @@ source "arch/sparc64/oprofile/Kconfig"
config KPROBES
bool "Kprobes (EXPERIMENTAL)"
depends on KALLSYMS && EXPERIMENTAL && MODULES
+ select FREEZER
help
Kprobes allows you to trap at almost any kernel address and
execute a callback function. register_kprobe() establishes
Index: linux-2.6.21-rc7-mm2/kernel/Makefile
===================================================================
--- linux-2.6.21-rc7-mm2.orig/kernel/Makefile 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/kernel/Makefile 2007-04-27 21:41:28.000000000 +0200
@@ -33,6 +33,7 @@ obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_STACK_UNWIND) += unwind.o
obj-$(CONFIG_PM) += power/
+obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_COMPAT) += compat.o
Index: linux-2.6.21-rc7-mm2/kernel/power/Makefile
===================================================================
--- linux-2.6.21-rc7-mm2.orig/kernel/power/Makefile 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/kernel/power/Makefile 2007-04-27 21:41:28.000000000 +0200
@@ -3,7 +3,7 @@ ifeq ($(CONFIG_PM_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
endif
-obj-y := main.o process.o console.o notify.o
+obj-y := main.o console.o notify.o
obj-$(CONFIG_PM_LEGACY) += pm.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o user.o
Index: linux-2.6.21-rc7-mm2/kernel/kprobes.c
===================================================================
--- linux-2.6.21-rc7-mm2.orig/kernel/kprobes.c 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/kernel/kprobes.c 2007-04-27 21:41:28.000000000 +0200
@@ -108,7 +108,7 @@ static int collect_garbage_slots(void);
static int __kprobes check_safety(void)
{
int ret = 0;
-#if defined(CONFIG_PREEMPT) && defined(CONFIG_PM)
+#ifdef CONFIG_PREEMPT
ret = freeze_processes();
if (ret == 0) {
struct task_struct *p, *q;
Index: linux-2.6.21-rc7-mm2/include/linux/freezer.h
===================================================================
--- linux-2.6.21-rc7-mm2.orig/include/linux/freezer.h 2007-04-27 21:41:27.000000000 +0200
+++ linux-2.6.21-rc7-mm2/include/linux/freezer.h 2007-04-27 23:20:23.000000000 +0200
@@ -2,7 +2,7 @@
#include <linux/sched.h>
-#ifdef CONFIG_PM
+#ifdef CONFIG_FREEZER
/*
* Check if a process has been frozen
*/
Index: linux-2.6.21-rc7-mm2/arch/arm/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/arm/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/arm/Kconfig 2007-04-27 23:11:10.000000000 +0200
@@ -925,6 +925,8 @@ config ARTHUR
endmenu
+source "kernel/Kconfig.freezer"
+
menu "Power management options"
source "kernel/power/Kconfig"
Index: linux-2.6.21-rc7-mm2/arch/blackfin/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/blackfin/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/blackfin/Kconfig 2007-04-27 23:13:09.000000000 +0200
@@ -816,6 +816,8 @@ source "fs/Kconfig.binfmt"
endmenu
+source "kernel/Kconfig.freezer"
+
menu "Power management options"
source "kernel/power/Kconfig"
Index: linux-2.6.21-rc7-mm2/arch/mips/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/mips/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/mips/Kconfig 2007-04-27 23:22:37.000000000 +0200
@@ -2067,6 +2067,8 @@ source "drivers/pci/hotplug/Kconfig"
endmenu
+source "kernel/Kconfig.freezer"
+
menu "Executable file formats"
source "fs/Kconfig.binfmt"
Index: linux-2.6.21-rc7-mm2/kernel/freezer.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.21-rc7-mm2/kernel/freezer.c 2007-04-27 23:20:23.000000000 +0200
@@ -0,0 +1,236 @@
+/*
+ * linux/kernel/freezer.c
+ *
+ * Generic mechanism for freezing and thawing tasks, originally from swsusp.
+ *
+ * Distributed under the GPLv2
+ */
+
+
+#undef DEBUG
+
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
+
+/*
+ * Timeout for stopping processes
+ */
+#define TIMEOUT (20 * HZ)
+
+#define FREEZER_KERNEL_THREADS 0
+#define FREEZER_USER_SPACE 1
+
+static inline int freezeable(struct task_struct * p)
+{
+ if ((p == current) ||
+ (p->flags & PF_NOFREEZE) ||
+ (p->exit_state != 0))
+ return 0;
+ 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_tsk_thread_flag(current, TIF_FREEZE);
+}
+
+/* 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(¤t->sighand->siglock);
+ recalc_sigpending(); /* We sent fake signal, clean it up */
+ spin_unlock_irq(¤t->sighand->siglock);
+
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (!frozen(current))
+ break;
+ schedule();
+ }
+ pr_debug("%s left refrigerator\n", current->comm);
+ current->state = save;
+}
+
+static inline void freeze_process(struct task_struct *p)
+{
+ unsigned long flags;
+
+ if (!freezing(p)) {
+ rmb();
+ if (!frozen(p)) {
+ if (p->state == TASK_STOPPED)
+ force_sig_specific(SIGSTOP, p);
+
+ freeze(p);
+ spin_lock_irqsave(&p->sighand->siglock, flags);
+ signal_wake_up(p, p->state == TASK_STOPPED);
+ 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);
+ }
+}
+
+static inline int is_user_space(struct task_struct *p)
+{
+ int ret;
+
+ task_lock(p);
+ ret = p->mm && !(p->flags & PF_BORROWED_MM);
+ task_unlock(p);
+ return ret;
+}
+
+static unsigned int try_to_freeze_tasks(int freeze_user_space)
+{
+ struct task_struct *g, *p;
+ unsigned long end_time;
+ unsigned int todo;
+
+ end_time = jiffies + TIMEOUT;
+ do {
+ todo = 0;
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ if (!freezeable(p))
+ continue;
+
+ if (frozen(p))
+ continue;
+
+ if (p->state == TASK_TRACED && frozen(p->parent)) {
+ cancel_freezing(p);
+ continue;
+ }
+ if (freeze_user_space && !is_user_space(p))
+ continue;
+
+ freeze_process(p);
+ if (!freezer_should_skip(p))
+ todo++;
+ } while_each_thread(g, p);
+ read_unlock(&tasklist_lock);
+ yield(); /* Yield is okay here */
+ if (todo && time_after(jiffies, end_time))
+ break;
+ } while (todo);
+
+ 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 "Stopping %s timed out after %d seconds "
+ "(%d tasks refusing to freeze):\n",
+ freeze_user_space ? "user space processes" :
+ "kernel threads",
+ TIMEOUT / HZ, todo);
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ if (freeze_user_space && !is_user_space(p))
+ continue;
+
+ task_lock(p);
+ if (freezeable(p) && !frozen(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);
+ }
+
+ return todo;
+}
+
+/**
+ * freeze_processes - tell processes to enter the refrigerator
+ *
+ * Returns 0 on success, or the number of processes that didn't freeze,
+ * although they were told to.
+ */
+int freeze_processes(void)
+{
+ unsigned int nr_unfrozen;
+
+ printk("Stopping tasks ... ");
+ nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE);
+ if (nr_unfrozen)
+ return nr_unfrozen;
+
+ sys_sync();
+ nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
+ if (nr_unfrozen)
+ return nr_unfrozen;
+
+ printk("done.\n");
+ BUG_ON(in_atomic());
+ return 0;
+}
+
+static void thaw_tasks(int thaw_user_space)
+{
+ struct task_struct *g, *p;
+
+ read_lock(&tasklist_lock);
+ do_each_thread(g, p) {
+ if (!freezeable(p))
+ continue;
+
+ if (is_user_space(p) == !thaw_user_space)
+ continue;
+
+ thaw_process(p);
+ } while_each_thread(g, p);
+ read_unlock(&tasklist_lock);
+}
+
+void thaw_processes(void)
+{
+ printk("Restarting tasks ... ");
+ thaw_tasks(FREEZER_KERNEL_THREADS);
+ thaw_tasks(FREEZER_USER_SPACE);
+ schedule();
+ printk("done.\n");
+}
+
+EXPORT_SYMBOL(refrigerator);
Index: linux-2.6.21-rc7-mm2/kernel/power/process.c
===================================================================
--- linux-2.6.21-rc7-mm2.orig/kernel/power/process.c 2007-04-27 21:41:27.000000000 +0200
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,236 +0,0 @@
-/*
- * drivers/power/process.c - Functions for starting/stopping processes on
- * suspend transitions.
- *
- * Originally from swsusp.
- */
-
-
-#undef DEBUG
-
-#include <linux/sched.h>
-#include <linux/interrupt.h>
-#include <linux/suspend.h>
-#include <linux/module.h>
-#include <linux/syscalls.h>
-#include <linux/freezer.h>
-
-/*
- * Timeout for stopping processes
- */
-#define TIMEOUT (20 * HZ)
-
-#define FREEZER_KERNEL_THREADS 0
-#define FREEZER_USER_SPACE 1
-
-static inline int freezeable(struct task_struct * p)
-{
- if ((p == current) ||
- (p->flags & PF_NOFREEZE) ||
- (p->exit_state != 0))
- return 0;
- 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_tsk_thread_flag(current, TIF_FREEZE);
-}
-
-/* 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(¤t->sighand->siglock);
- recalc_sigpending(); /* We sent fake signal, clean it up */
- spin_unlock_irq(¤t->sighand->siglock);
-
- for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (!frozen(current))
- break;
- schedule();
- }
- pr_debug("%s left refrigerator\n", current->comm);
- current->state = save;
-}
-
-static inline void freeze_process(struct task_struct *p)
-{
- unsigned long flags;
-
- if (!freezing(p)) {
- rmb();
- if (!frozen(p)) {
- if (p->state == TASK_STOPPED)
- force_sig_specific(SIGSTOP, p);
-
- freeze(p);
- spin_lock_irqsave(&p->sighand->siglock, flags);
- signal_wake_up(p, p->state == TASK_STOPPED);
- 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);
- }
-}
-
-static inline int is_user_space(struct task_struct *p)
-{
- int ret;
-
- task_lock(p);
- ret = p->mm && !(p->flags & PF_BORROWED_MM);
- task_unlock(p);
- return ret;
-}
-
-static unsigned int try_to_freeze_tasks(int freeze_user_space)
-{
- struct task_struct *g, *p;
- unsigned long end_time;
- unsigned int todo;
-
- end_time = jiffies + TIMEOUT;
- do {
- todo = 0;
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- if (!freezeable(p))
- continue;
-
- if (frozen(p))
- continue;
-
- if (p->state == TASK_TRACED && frozen(p->parent)) {
- cancel_freezing(p);
- continue;
- }
- if (freeze_user_space && !is_user_space(p))
- continue;
-
- freeze_process(p);
- if (!freezer_should_skip(p))
- todo++;
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
- yield(); /* Yield is okay here */
- if (todo && time_after(jiffies, end_time))
- break;
- } while (todo);
-
- 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 "Stopping %s timed out after %d seconds "
- "(%d tasks refusing to freeze):\n",
- freeze_user_space ? "user space processes" :
- "kernel threads",
- TIMEOUT / HZ, todo);
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- if (freeze_user_space && !is_user_space(p))
- continue;
-
- task_lock(p);
- if (freezeable(p) && !frozen(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);
- }
-
- return todo;
-}
-
-/**
- * freeze_processes - tell processes to enter the refrigerator
- *
- * Returns 0 on success, or the number of processes that didn't freeze,
- * although they were told to.
- */
-int freeze_processes(void)
-{
- unsigned int nr_unfrozen;
-
- printk("Stopping tasks ... ");
- nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE);
- if (nr_unfrozen)
- return nr_unfrozen;
-
- sys_sync();
- nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
- if (nr_unfrozen)
- return nr_unfrozen;
-
- printk("done.\n");
- BUG_ON(in_atomic());
- return 0;
-}
-
-static void thaw_tasks(int thaw_user_space)
-{
- struct task_struct *g, *p;
-
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- if (!freezeable(p))
- continue;
-
- if (is_user_space(p) == !thaw_user_space)
- continue;
-
- thaw_process(p);
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
-}
-
-void thaw_processes(void)
-{
- printk("Restarting tasks ... ");
- thaw_tasks(FREEZER_KERNEL_THREADS);
- thaw_tasks(FREEZER_USER_SPACE);
- schedule();
- printk("done.\n");
-}
-
-EXPORT_SYMBOL(refrigerator);
Index: linux-2.6.21-rc7-mm2/arch/avr32/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/arch/avr32/Kconfig 2007-04-27 01:00:50.000000000 +0200
+++ linux-2.6.21-rc7-mm2/arch/avr32/Kconfig 2007-04-27 23:12:42.000000000 +0200
@@ -209,6 +209,8 @@ source "drivers/Kconfig"
source "fs/Kconfig"
+source "kernel/Kconfig.freezer"
+
source "arch/avr32/Kconfig.debug"
source "security/Kconfig"
Index: linux-2.6.21-rc7-mm2/kernel/power/Kconfig
===================================================================
--- linux-2.6.21-rc7-mm2.orig/kernel/power/Kconfig 2007-04-27 21:41:05.000000000 +0200
+++ linux-2.6.21-rc7-mm2/kernel/power/Kconfig 2007-04-27 21:42:52.000000000 +0200
@@ -1,6 +1,7 @@
config PM
bool "Power Management support"
depends on !IA64_HP_SIM
+ select FREEZER
---help---
"Power Management" means that parts of your computer are shut
off or put into a power conserving "sleep" mode if they are not
Index: linux-2.6.21-rc7-mm2/kernel/Kconfig.freezer
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.21-rc7-mm2/kernel/Kconfig.freezer 2007-04-27 23:06:52.000000000 +0200
@@ -0,0 +1,5 @@
+# Tasks freezer configuration
+
+config FREEZER
+ bool
+ default n
-
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