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Message-ID: <20070429084318.GA6635@uranus.ravnborg.org>
Date: Sun, 29 Apr 2007 10:43:18 +0200
From: Sam Ravnborg <sam@...nborg.org>
To: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Jeremy Fitzhardinge <jeremy@...p.org>,
Andrew Morton <akpm@...ux-foundation.org>,
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: Re: [PATCH -mm 1/2] Separate freezer from PM code
On Fri, Apr 27, 2007 at 11:29:34PM +0200, Rafael J. Wysocki wrote:
> On Friday, 27 April 2007 22:20, Jeremy Fitzhardinge wrote:
> > Rafael J. Wysocki wrote:
> > > Makes sense. Please have a look at the updated patch below.
> > >
> > > Sam, does this one look better to you?
> > >
> >
> > If freezer.c is in kernel/, then shouldn't the corresponding config var
> > be in a non-arch Kconfig file?
>
> Well, I though it would look strange. Still, I can do that, of course:
It would have been much better to have a single kernel/Kconfig
so you avoided all the arch specific source lines.
But thats not this patch and can come later.
So I'm OK with this one.
Sam
>
> ---
> 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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