diff options
| -rw-r--r-- | arch/alpha/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/Kconfig | 2 | ||||
| -rw-r--r-- | arch/avr32/Kconfig | 2 | ||||
| -rw-r--r-- | arch/blackfin/Kconfig | 3 | ||||
| -rw-r--r-- | arch/cris/Kconfig | 2 | ||||
| -rw-r--r-- | arch/frv/Kconfig | 2 | ||||
| -rw-r--r-- | arch/h8300/Kconfig | 2 | ||||
| -rw-r--r-- | arch/ia64/Kconfig | 2 | ||||
| -rw-r--r-- | arch/m32r/Kconfig | 2 | ||||
| -rw-r--r-- | arch/m68k/Kconfig | 2 | ||||
| -rw-r--r-- | arch/m68knommu/Kconfig | 2 | ||||
| -rw-r--r-- | arch/mips/Kconfig | 2 | ||||
| -rw-r--r-- | arch/mn10300/Kconfig | 2 | ||||
| -rw-r--r-- | arch/parisc/Kconfig | 2 | ||||
| -rw-r--r-- | arch/powerpc/Kconfig | 2 | ||||
| -rw-r--r-- | arch/s390/Kconfig | 2 | ||||
| -rw-r--r-- | arch/sh/Kconfig | 2 | ||||
| -rw-r--r-- | arch/sparc/Kconfig | 2 | ||||
| -rw-r--r-- | arch/sparc64/Kconfig | 1 | ||||
| -rw-r--r-- | arch/um/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/xtensa/Kconfig | 1 | ||||
| -rw-r--r-- | include/linux/cgroup_subsys.h | 6 | ||||
| -rw-r--r-- | include/linux/freezer.h | 29 | ||||
| -rw-r--r-- | init/Kconfig | 7 | ||||
| -rw-r--r-- | kernel/Kconfig.freezer | 2 | ||||
| -rw-r--r-- | kernel/Makefile | 1 | ||||
| -rw-r--r-- | kernel/cgroup_freezer.c | 366 | ||||
| -rw-r--r-- | kernel/freezer.c | 32 | ||||
| -rw-r--r-- | kernel/power/Kconfig | 3 |
30 files changed, 465 insertions, 22 deletions
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index a0f642b6a4b..6110197757a 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -70,6 +70,7 @@ config AUTO_IRQ_AFFINITY default y source "init/Kconfig" +source "kernel/Kconfig.freezer" menu "System setup" diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 4853f9df37b..df39d20f742 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -192,6 +192,8 @@ config VECTORS_BASE source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "System Type" choice diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig index 7c239a91627..33a5b2969eb 100644 --- a/arch/avr32/Kconfig +++ b/arch/avr32/Kconfig @@ -72,6 +72,8 @@ config GENERIC_BUG source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "System Type and features" source "kernel/time/Kconfig" diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index 8102c79aaa9..29e71ed6b8a 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -64,8 +64,11 @@ config HARDWARE_PM depends on OPROFILE source "init/Kconfig" + source "kernel/Kconfig.preempt" +source "kernel/Kconfig.freezer" + menu "Blackfin Processor Options" comment "Processor and Board Settings" diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig index 9389d38f222..07335e719bf 100644 --- a/arch/cris/Kconfig +++ b/arch/cris/Kconfig @@ -62,6 +62,8 @@ config HZ source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "General setup" source "fs/Kconfig.binfmt" diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig index a5aac1b0756..9d1552a9ee2 100644 --- a/arch/frv/Kconfig +++ b/arch/frv/Kconfig @@ -66,6 +66,8 @@ mainmenu "Fujitsu FR-V Kernel Configuration" source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Fujitsu FR-V system setup" diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig index c7966746fbf..bd1995403c6 100644 --- a/arch/h8300/Kconfig +++ b/arch/h8300/Kconfig @@ -90,6 +90,8 @@ config HZ source "init/Kconfig" +source "kernel/Kconfig.freezer" + source "arch/h8300/Kconfig.cpu" menu "Executable file formats" diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 3b7aa38254a..912c57db2d2 100644 --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -7,6 +7,8 @@ mainmenu "IA-64 Linux Kernel Configuration" source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Processor type and features" config IA64 diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig index 00289c178f8..dbaed4a6381 100644 --- a/arch/m32r/Kconfig +++ b/arch/m32r/Kconfig @@ -42,6 +42,8 @@ config HZ source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Processor type and features" diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig index 677c93a490f..836fb66f080 100644 --- a/arch/m68k/Kconfig +++ b/arch/m68k/Kconfig @@ -62,6 +62,8 @@ mainmenu "Linux/68k Kernel Configuration" source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Platform dependent setup" config EISA diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig index 0a8998315e5..76b66feb74d 100644 --- a/arch/m68knommu/Kconfig +++ b/arch/m68knommu/Kconfig @@ -75,6 +75,8 @@ config NO_IOPORT source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Processor type and features" choice diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index b905744d791..5f149b030c0 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1885,6 +1885,8 @@ config PROBE_INITRD_HEADER add initrd or initramfs image to the kernel image. Otherwise, say N. +source "kernel/Kconfig.freezer" + menu "Bus options (PCI, PCMCIA, EISA, ISA, TC)" config HW_HAS_EISA diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig index dd557c9cf00..9a9f4335887 100644 --- a/arch/mn10300/Kconfig +++ b/arch/mn10300/Kconfig @@ -68,6 +68,8 @@ mainmenu "Matsushita MN10300/AM33 Kernel Configuration" source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Matsushita MN10300 system setup" diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 8313fccced5..2bd1f6ef5db 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -90,6 +90,8 @@ config ARCH_MAY_HAVE_PC_FDC source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Processor type and features" diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 380baa1780e..9391199d9e7 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -230,6 +230,8 @@ config PPC_OF_PLATFORM_PCI source "init/Kconfig" +source "kernel/Kconfig.freezer" + source "arch/powerpc/sysdev/Kconfig" source "arch/powerpc/platforms/Kconfig" diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index bc581d8a7cd..70b7645ce74 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -78,6 +78,8 @@ config S390 source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "Base setup" comment "Processor type and features" diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 5131d50f851..2ed5713b754 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -106,6 +106,8 @@ config IO_TRAPPED source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "System type" # diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 97671dac12a..e594559c8db 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -37,6 +37,8 @@ config HZ source "init/Kconfig" +source "kernel/Kconfig.freezer" + menu "General machine setup" config SMP diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig index 5446e2a499b..035b15af90d 100644 --- a/arch/sparc64/Kconfig +++ b/arch/sparc64/Kconfig @@ -96,6 +96,7 @@ config GENERIC_HARDIRQS_NO__DO_IRQ def_bool y source "init/Kconfig" +source "kernel/Kconfig.freezer" menu "Processor type and features" diff --git a/arch/um/Kconfig b/arch/um/Kconfig index 6976812cfb1..393bccfe178 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -229,6 +229,8 @@ endmenu source "init/Kconfig" +source "kernel/Kconfig.freezer" + source "drivers/block/Kconfig" source "arch/um/Kconfig.char" diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index bd3c2c53873..49349ba77d8 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -193,6 +193,7 @@ config X86_TRAMPOLINE config KTIME_SCALAR def_bool X86_32 source "init/Kconfig" +source "kernel/Kconfig.freezer" menu "Processor type and features" diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 02e417d3d8e..a213260b51e 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -55,6 +55,7 @@ config HZ default 100 source "init/Kconfig" +source "kernel/Kconfig.freezer" menu "Processor type and features" diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h index e2877454ec8..9c22396e8b5 100644 --- a/include/linux/cgroup_subsys.h +++ b/include/linux/cgroup_subsys.h @@ -48,3 +48,9 @@ SUBSYS(devices) #endif /* */ + +#ifdef CONFIG_CGROUP_FREEZER +SUBSYS(freezer) +#endif + +/* */ diff --git a/include/linux/freezer.h b/include/linux/freezer.h index 17e3bb42dd3..8f225339eee 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -46,26 +46,11 @@ static inline bool should_send_signal(struct task_struct *p) /* * Wake up a frozen process - * - * task_lock() is taken to prevent the race with refrigerator() which may - * occur if the freezing of tasks fails. Namely, without the lock, if the - * freezing of tasks failed, thaw_tasks() might have run before a task in - * refrigerator() could call frozen_process(), in which case the task would be - * frozen and no one would thaw it. */ -static inline int thaw_process(struct task_struct *p) -{ - task_lock(p); - if (frozen(p)) { - p->flags &= ~PF_FROZEN; - task_unlock(p); - wake_up_process(p); - return 1; - } - clear_freeze_flag(p); - task_unlock(p); - return 0; -} +extern int __thaw_process(struct task_struct *p); + +/* Takes and releases task alloc lock using task_lock() */ +extern int thaw_process(struct task_struct *p); extern void refrigerator(void); extern int freeze_processes(void); @@ -83,6 +68,12 @@ static inline int try_to_freeze(void) extern bool freeze_task(struct task_struct *p, bool sig_only); extern void cancel_freezing(struct task_struct *p); +#ifdef CONFIG_CGROUP_FREEZER +extern int cgroup_frozen(struct task_struct *task); +#else /* !CONFIG_CGROUP_FREEZER */ +static inline int cgroup_frozen(struct task_struct *task) { return 0; } +#endif /* !CONFIG_CGROUP_FREEZER */ + /* * 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 diff --git a/init/Kconfig b/init/Kconfig index 5ceff3249a2..8828ed0b205 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -299,6 +299,13 @@ config CGROUP_NS for instance virtual servers and checkpoint/restart jobs. +config CGROUP_FREEZER + bool "control group freezer subsystem" + depends on CGROUPS + help + Provides a way to freeze and unfreeze all tasks in a + cgroup. + config CGROUP_DEVICE bool "Device controller for cgroups" depends on CGROUPS && EXPERIMENTAL diff --git a/kernel/Kconfig.freezer b/kernel/Kconfig.freezer new file mode 100644 index 00000000000..a3bb4cb5253 --- /dev/null +++ b/kernel/Kconfig.freezer @@ -0,0 +1,2 @@ +config FREEZER + def_bool PM_SLEEP || CGROUP_FREEZER diff --git a/kernel/Makefile b/kernel/Makefile index e8194d15d5f..066550aa61c 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -56,6 +56,7 @@ obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o obj-$(CONFIG_COMPAT) += compat.o obj-$(CONFIG_CGROUPS) += cgroup.o obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o +obj-$(CONFIG_CGROUP_FREEZER) += cgroup_freezer.o obj-$(CONFIG_CPUSETS) += cpuset.o obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o obj-$(CONFIG_UTS_NS) += utsname.o diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c new file mode 100644 index 00000000000..b08722de610 --- /dev/null +++ b/kernel/cgroup_freezer.c @@ -0,0 +1,366 @@ +/* + * cgroup_freezer.c - control group freezer subsystem + * + * Copyright IBM Corporation, 2007 + * + * Author : Cedric Le Goater <clg@fr.ibm.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2.1 of the GNU Lesser General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + */ + +#include <linux/module.h> +#include <linux/cgroup.h> +#include <linux/fs.h> +#include <linux/uaccess.h> +#include <linux/freezer.h> +#include <linux/seq_file.h> + +enum freezer_state { + STATE_RUNNING = 0, + STATE_FREEZING, + STATE_FROZEN, +}; + +struct freezer { + struct cgroup_subsys_state css; + enum freezer_state state; + spinlock_t lock; /* protects _writes_ to state */ +}; + +static inline struct freezer *cgroup_freezer( + struct cgroup *cgroup) +{ + return container_of( + cgroup_subsys_state(cgroup, freezer_subsys_id), + struct freezer, css); +} + +static inline struct freezer *task_freezer(struct task_struct *task) +{ + return container_of(task_subsys_state(task, freezer_subsys_id), + struct freezer, css); +} + +int cgroup_frozen(struct task_struct *task) +{ + struct freezer *freezer; + enum freezer_state state; + + task_lock(task); + freezer = task_freezer(task); + state = freezer->state; + task_unlock(task); + + return state == STATE_FROZEN; +} + +/* + * cgroups_write_string() limits the size of freezer state strings to + * CGROUP_LOCAL_BUFFER_SIZE + */ +static const char *freezer_state_strs[] = { + "RUNNING", + "FREEZING", + "FROZEN", +}; + +/* + * State diagram + * Transitions are caused by userspace writes to the freezer.state file. + * The values in parenthesis are state labels. The rest are edge labels. + * + * (RUNNING) --FROZEN--> (FREEZING) --FROZEN--> (FROZEN) + * ^ ^ | | + * | \_______RUNNING_______/ | + * \_____________________________RUNNING___________/ + */ + +struct cgroup_subsys freezer_subsys; + +/* Locks taken and their ordering + * ------------------------------ + * css_set_lock + * cgroup_mutex (AKA cgroup_lock) + * task->alloc_lock (AKA task_lock) + * freezer->lock + * task->sighand->siglock + * + * cgroup code forces css_set_lock to be taken before task->alloc_lock + * + * freezer_create(), freezer_destroy(): + * cgroup_mutex [ by cgroup core ] + * + * can_attach(): + * cgroup_mutex + * + * cgroup_frozen(): + * task->alloc_lock (to get task's cgroup) + * + * freezer_fork() (preserving fork() performance means can't take cgroup_mutex): + * task->alloc_lock (to get task's cgroup) + * freezer->lock + * sighand->siglock (if the cgroup is freezing) + * + * freezer_read(): + * cgroup_mutex + * freezer->lock + * read_lock css_set_lock (cgroup iterator start) + * + * freezer_write() (freeze): + * cgroup_mutex + * freezer->lock + * read_lock css_set_lock (cgroup iterator start) + * sighand->siglock + * + * freezer_write() (unfreeze): + * cgroup_mutex + * freezer->lock + * read_lock css_set_lock (cgroup iterator start) + * task->alloc_lock (to prevent races with freeze_task()) + * sighand->siglock + */ +static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss, + struct cgroup *cgroup) +{ + struct freezer *freezer; + + freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL); + if (!freezer) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&freezer->lock); + freezer->state = STATE_RUNNING; + return &freezer->css; +} + +static void freezer_destroy(struct cgroup_subsys *ss, + struct cgroup *cgroup) +{ + kfree(cgroup_freezer(cgroup)); +} + + +static int freezer_can_attach(struct cgroup_subsys *ss, + struct cgroup *new_cgroup, + struct task_struct *task) +{ + struct freezer *freezer; + int retval = 0; + + /* + * The call to cgroup_lock() in the freezer.state write method prevents + * a write to that file racing against an attach, and hence the + * can_attach() result will remain valid until the attach completes. + */ + freezer = cgroup_freezer(new_cgroup); + if (freezer->state == STATE_FROZEN) + retval = -EBUSY; + return retval; +} + +static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task) +{ + struct freezer *freezer; + + task_lock(task); + freezer = task_freezer(task); + task_unlock(task); + + BUG_ON(freezer->state == STATE_FROZEN); + spin_lock_irq(&freezer->lock); + /* Locking avoids race with FREEZING -> RUNNING transitions. */ + if (freezer->state == STATE_FREEZING) + freeze_task(task, true); + spin_unlock_irq(&freezer->lock); +} + +/* + * caller must hold freezer->lock + */ +static void check_if_frozen(struct cgroup *cgroup, + struct freezer *freezer) +{ + struct cgroup_iter it; + struct task_struct *task; + unsigned int nfrozen = 0, ntotal = 0; + + cgroup_iter_start(cgroup, &it); + while ((task = cgroup_iter_next(cgroup, &it))) { + ntotal++; + /* + * Task is frozen or will freeze immediately when next it gets + * woken + */ + if (frozen(task) || + (task_is_stopped_or_traced(task) && freezing(task))) + nfrozen++; + } + + /* + * Transition to FROZEN when no new tasks can be added ensures + * that we never exist in the FROZEN state while there are unfrozen + * tasks. + */ + if (nfrozen == ntotal) + freezer->state = STATE_FROZEN; + cgroup_iter_end(cgroup, &it); +} + +static int freezer_read(struct cgroup *cgroup, struct cftype *cft, + struct seq_file *m) +{ + struct freezer *freezer; + enum freezer_state state; + + if (!cgroup_lock_live_group(cgroup)) + return -ENODEV; + + freezer = cgroup_freezer(cgroup); + spin_lock_irq(&freezer->lock); + state = freezer->state; + if (state == STATE_FREEZING) { + /* We change from FREEZING to FROZEN lazily if the cgroup was + * only partially frozen when we exitted write. */ + check_if_frozen(cgroup, freezer); + state = freezer->state; + } + spin_unlock_irq(&freezer->lock); + cgroup_unlock(); + + seq_puts(m, freezer_state_strs[state]); + seq_putc(m, '\n'); + return 0; +} + +static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer) +{ + struct cgroup_iter it; + struct task_struct *task; + unsigned int num_cant_freeze_now = 0; + + freezer->state = STATE_FREEZING; + cgroup_iter_start(cgroup, &it); + while ((task = cgroup_iter_next(cgroup, &it))) { + if (!freeze_task(task, true)) + continue; + if (task_is_stopped_or_traced(task) && freezing(task)) + /* + * The freeze flag is set so these tasks will + * immediately go into the fridge upon waking. + */ + continue; + if (!freezing(task) && !freezer_should_skip(task)) + num_cant_freeze_now++; + } + cgroup_iter_end(cgroup, &it); + + return num_cant_freeze_now ? -EBUSY : 0; +} + +static int unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer) +{ + struct cgroup_iter it; + struct task_struct *task; + + cgroup_iter_start(cgroup, &it); + while ((task = cgroup_iter_next(cgroup, &it))) { + int do_wake; + + task_lock(task); + do_wake = __thaw_process(task); + task_unlock(task); + if (do_wake) + wake_up_process(task); + } + cgroup_iter_end(cgroup, &it); + freezer->state = STATE_RUNNING; + + return 0; +} + +static int freezer_change_state(struct cgroup *cgroup, + enum freezer_state goal_state) +{ + struct freezer *freezer; + int retval = 0; + + freezer = cgroup_freezer(cgroup); + spin_lock_irq(&freezer->lock); + check_if_frozen(cgroup, freezer); /* may update freezer->state */ + if (goal_state == freezer->state) + goto out; + switch (freezer->state) { + case STATE_RUNNING: + retval = try_to_freeze_cgroup(cgroup, freezer); + break; + case STATE_FREEZING: + if (goal_state == STATE_FROZEN) { + /* Userspace is retrying after + * "/bin/echo FROZEN > freezer.state" returned -EBUSY */ + retval = try_to_freeze_cgroup(cgroup, freezer); + break; + } + /* state == FREEZING and goal_state == RUNNING, so unfreeze */ + case STATE_FROZEN: + retval = unfreeze_cgroup(cgroup, freezer); + break; + default: + break; + } +out: + spin_unlock_irq(&freezer->lock); + + return retval; +} + +static int freezer_write(struct cgroup *cgroup, + struct cftype *cft, + const char *buffer) +{ + int retval; + enum freezer_state goal_state; + + if (strcmp(buffer, freezer_state_strs[STATE_RUNNING]) == 0) + goal_state = STATE_RUNNING; + else if (strcmp(buffer, freezer_state_strs[STATE_FROZEN]) == 0) + goal_state = STATE_FROZEN; + else + return -EIO; + + if (!cgroup_lock_live_group(cgroup)) + return -ENODEV; + retval = freezer_change_state(cgroup, goal_state); + cgroup_unlock(); + return retval; +} + +static struct cftype files[] = { + { + .name = "state", + .read_seq_string = freezer_read, + .write_string = freezer_write, + }, +}; + +static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup) +{ + return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files)); +} + +struct cgroup_subsys freezer_subsys = { + .name = "freezer", + .create = freezer_create, + .destroy = freezer_destroy, + .populate = freezer_populate, + .subsys_id = freezer_subsys_id, + .can_attach = freezer_can_attach, + .attach = NULL, + .fork = freezer_fork, + .exit = NULL, +}; diff --git a/kernel/freezer.c b/kernel/freezer.c index cb0931f8930..ba6248b323e 100644 --- a/kernel/freezer.c +++ b/kernel/freezer.c @@ -120,3 +120,35 @@ void cancel_freezing(struct task_struct *p) spin_unlock_irqrestore(&p->sighand->siglock, flags); } } + +/* + * Wake up a frozen process + * + * task_lock() is needed to prevent the race with refrigerator() which may + * occur if the freezing of tasks fails. Namely, without the lock, if the + * freezing of tasks failed, thaw_tasks() might have run before a task in + * refrigerator() could call frozen_process(), in which case the task would be + * frozen and no one would thaw it. + */ +int __thaw_process(struct task_struct *p) +{ + if (frozen(p)) { + p->flags &= ~PF_FROZEN; + return 1; + } + clear_freeze_flag(p); + return 0; +} + +int thaw_process(struct task_struct *p) +{ + task_lock(p); + if (__thaw_process(p) == 1) { + task_unlock(p); + wake_up_process(p); + return 1; + } + task_unlock(p); + return 0; +} +EXPORT_SYMBOL(thaw_process); diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index ebdd7f55273..dcd165f92a8 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -85,9 +85,6 @@ 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 |