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-rw-r--r--arch/alpha/Kconfig1
-rw-r--r--arch/arm/Kconfig2
-rw-r--r--arch/avr32/Kconfig2
-rw-r--r--arch/blackfin/Kconfig3
-rw-r--r--arch/cris/Kconfig2
-rw-r--r--arch/frv/Kconfig2
-rw-r--r--arch/h8300/Kconfig2
-rw-r--r--arch/ia64/Kconfig2
-rw-r--r--arch/m32r/Kconfig2
-rw-r--r--arch/m68k/Kconfig2
-rw-r--r--arch/m68knommu/Kconfig2
-rw-r--r--arch/mips/Kconfig2
-rw-r--r--arch/mn10300/Kconfig2
-rw-r--r--arch/parisc/Kconfig2
-rw-r--r--arch/powerpc/Kconfig2
-rw-r--r--arch/s390/Kconfig2
-rw-r--r--arch/sh/Kconfig2
-rw-r--r--arch/sparc/Kconfig2
-rw-r--r--arch/sparc64/Kconfig1
-rw-r--r--arch/um/Kconfig2
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/xtensa/Kconfig1
-rw-r--r--include/linux/cgroup_subsys.h6
-rw-r--r--include/linux/freezer.h29
-rw-r--r--init/Kconfig7
-rw-r--r--kernel/Kconfig.freezer2
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/cgroup_freezer.c366
-rw-r--r--kernel/freezer.c32
-rw-r--r--kernel/power/Kconfig3
30 files changed, 465 insertions, 22 deletions
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index a0f642b6a4b9..6110197757a3 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -70,6 +70,7 @@ config AUTO_IRQ_AFFINITY
70 default y 70 default y
71 71
72source "init/Kconfig" 72source "init/Kconfig"
73source "kernel/Kconfig.freezer"
73 74
74 75
75menu "System setup" 76menu "System setup"
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4853f9df37bd..df39d20f7425 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -192,6 +192,8 @@ config VECTORS_BASE
192 192
193source "init/Kconfig" 193source "init/Kconfig"
194 194
195source "kernel/Kconfig.freezer"
196
195menu "System Type" 197menu "System Type"
196 198
197choice 199choice
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index 7c239a916275..33a5b2969eb4 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -72,6 +72,8 @@ config GENERIC_BUG
72 72
73source "init/Kconfig" 73source "init/Kconfig"
74 74
75source "kernel/Kconfig.freezer"
76
75menu "System Type and features" 77menu "System Type and features"
76 78
77source "kernel/time/Kconfig" 79source "kernel/time/Kconfig"
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index 8102c79aaa94..29e71ed6b8a7 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -64,8 +64,11 @@ config HARDWARE_PM
64 depends on OPROFILE 64 depends on OPROFILE
65 65
66source "init/Kconfig" 66source "init/Kconfig"
67
67source "kernel/Kconfig.preempt" 68source "kernel/Kconfig.preempt"
68 69
70source "kernel/Kconfig.freezer"
71
69menu "Blackfin Processor Options" 72menu "Blackfin Processor Options"
70 73
71comment "Processor and Board Settings" 74comment "Processor and Board Settings"
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 9389d38f222f..07335e719bf8 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -62,6 +62,8 @@ config HZ
62 62
63source "init/Kconfig" 63source "init/Kconfig"
64 64
65source "kernel/Kconfig.freezer"
66
65menu "General setup" 67menu "General setup"
66 68
67source "fs/Kconfig.binfmt" 69source "fs/Kconfig.binfmt"
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index a5aac1b07562..9d1552a9ee2c 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -66,6 +66,8 @@ mainmenu "Fujitsu FR-V Kernel Configuration"
66 66
67source "init/Kconfig" 67source "init/Kconfig"
68 68
69source "kernel/Kconfig.freezer"
70
69 71
70menu "Fujitsu FR-V system setup" 72menu "Fujitsu FR-V system setup"
71 73
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index c7966746fbfe..bd1995403c67 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -90,6 +90,8 @@ config HZ
90 90
91source "init/Kconfig" 91source "init/Kconfig"
92 92
93source "kernel/Kconfig.freezer"
94
93source "arch/h8300/Kconfig.cpu" 95source "arch/h8300/Kconfig.cpu"
94 96
95menu "Executable file formats" 97menu "Executable file formats"
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 3b7aa38254a8..912c57db2d21 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -7,6 +7,8 @@ mainmenu "IA-64 Linux Kernel Configuration"
7 7
8source "init/Kconfig" 8source "init/Kconfig"
9 9
10source "kernel/Kconfig.freezer"
11
10menu "Processor type and features" 12menu "Processor type and features"
11 13
12config IA64 14config IA64
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index 00289c178f89..dbaed4a63815 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -42,6 +42,8 @@ config HZ
42 42
43source "init/Kconfig" 43source "init/Kconfig"
44 44
45source "kernel/Kconfig.freezer"
46
45 47
46menu "Processor type and features" 48menu "Processor type and features"
47 49
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 677c93a490f6..836fb66f080d 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -62,6 +62,8 @@ mainmenu "Linux/68k Kernel Configuration"
62 62
63source "init/Kconfig" 63source "init/Kconfig"
64 64
65source "kernel/Kconfig.freezer"
66
65menu "Platform dependent setup" 67menu "Platform dependent setup"
66 68
67config EISA 69config EISA
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index 0a8998315e5e..76b66feb74df 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -75,6 +75,8 @@ config NO_IOPORT
75 75
76source "init/Kconfig" 76source "init/Kconfig"
77 77
78source "kernel/Kconfig.freezer"
79
78menu "Processor type and features" 80menu "Processor type and features"
79 81
80choice 82choice
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index b905744d7915..5f149b030c0f 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1885,6 +1885,8 @@ config PROBE_INITRD_HEADER
1885 add initrd or initramfs image to the kernel image. 1885 add initrd or initramfs image to the kernel image.
1886 Otherwise, say N. 1886 Otherwise, say N.
1887 1887
1888source "kernel/Kconfig.freezer"
1889
1888menu "Bus options (PCI, PCMCIA, EISA, ISA, TC)" 1890menu "Bus options (PCI, PCMCIA, EISA, ISA, TC)"
1889 1891
1890config HW_HAS_EISA 1892config HW_HAS_EISA
diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index dd557c9cf001..9a9f43358879 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -68,6 +68,8 @@ mainmenu "Matsushita MN10300/AM33 Kernel Configuration"
68 68
69source "init/Kconfig" 69source "init/Kconfig"
70 70
71source "kernel/Kconfig.freezer"
72
71 73
72menu "Matsushita MN10300 system setup" 74menu "Matsushita MN10300 system setup"
73 75
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 8313fccced5e..2bd1f6ef5db0 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -90,6 +90,8 @@ config ARCH_MAY_HAVE_PC_FDC
90 90
91source "init/Kconfig" 91source "init/Kconfig"
92 92
93source "kernel/Kconfig.freezer"
94
93 95
94menu "Processor type and features" 96menu "Processor type and features"
95 97
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 380baa1780e9..9391199d9e77 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -230,6 +230,8 @@ config PPC_OF_PLATFORM_PCI
230 230
231source "init/Kconfig" 231source "init/Kconfig"
232 232
233source "kernel/Kconfig.freezer"
234
233source "arch/powerpc/sysdev/Kconfig" 235source "arch/powerpc/sysdev/Kconfig"
234source "arch/powerpc/platforms/Kconfig" 236source "arch/powerpc/platforms/Kconfig"
235 237
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index bc581d8a7cd9..70b7645ce745 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -78,6 +78,8 @@ config S390
78 78
79source "init/Kconfig" 79source "init/Kconfig"
80 80
81source "kernel/Kconfig.freezer"
82
81menu "Base setup" 83menu "Base setup"
82 84
83comment "Processor type and features" 85comment "Processor type and features"
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 5131d50f851a..2ed5713b7540 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -106,6 +106,8 @@ config IO_TRAPPED
106 106
107source "init/Kconfig" 107source "init/Kconfig"
108 108
109source "kernel/Kconfig.freezer"
110
109menu "System type" 111menu "System type"
110 112
111# 113#
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 97671dac12a6..e594559c8dba 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -37,6 +37,8 @@ config HZ
37 37
38source "init/Kconfig" 38source "init/Kconfig"
39 39
40source "kernel/Kconfig.freezer"
41
40menu "General machine setup" 42menu "General machine setup"
41 43
42config SMP 44config SMP
diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index 5446e2a499b1..035b15af90d8 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -96,6 +96,7 @@ config GENERIC_HARDIRQS_NO__DO_IRQ
96 def_bool y 96 def_bool y
97 97
98source "init/Kconfig" 98source "init/Kconfig"
99source "kernel/Kconfig.freezer"
99 100
100menu "Processor type and features" 101menu "Processor type and features"
101 102
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 6976812cfb18..393bccfe1785 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -229,6 +229,8 @@ endmenu
229 229
230source "init/Kconfig" 230source "init/Kconfig"
231 231
232source "kernel/Kconfig.freezer"
233
232source "drivers/block/Kconfig" 234source "drivers/block/Kconfig"
233 235
234source "arch/um/Kconfig.char" 236source "arch/um/Kconfig.char"
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bd3c2c53873e..49349ba77d80 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -193,6 +193,7 @@ config X86_TRAMPOLINE
193config KTIME_SCALAR 193config KTIME_SCALAR
194 def_bool X86_32 194 def_bool X86_32
195source "init/Kconfig" 195source "init/Kconfig"
196source "kernel/Kconfig.freezer"
196 197
197menu "Processor type and features" 198menu "Processor type and features"
198 199
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 02e417d3d8e9..a213260b51e5 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -55,6 +55,7 @@ config HZ
55 default 100 55 default 100
56 56
57source "init/Kconfig" 57source "init/Kconfig"
58source "kernel/Kconfig.freezer"
58 59
59menu "Processor type and features" 60menu "Processor type and features"
60 61
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index e2877454ec82..9c22396e8b50 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -48,3 +48,9 @@ SUBSYS(devices)
48#endif 48#endif
49 49
50/* */ 50/* */
51
52#ifdef CONFIG_CGROUP_FREEZER
53SUBSYS(freezer)
54#endif
55
56/* */
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index 17e3bb42dd3c..8f225339eee9 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)
46 46
47/* 47/*
48 * Wake up a frozen process 48 * Wake up a frozen process
49 *
50 * task_lock() is taken to prevent the race with refrigerator() which may
51 * occur if the freezing of tasks fails. Namely, without the lock, if the
52 * freezing of tasks failed, thaw_tasks() might have run before a task in
53 * refrigerator() could call frozen_process(), in which case the task would be
54 * frozen and no one would thaw it.
55 */ 49 */
56static inline int thaw_process(struct task_struct *p) 50extern int __thaw_process(struct task_struct *p);
57{ 51
58 task_lock(p); 52/* Takes and releases task alloc lock using task_lock() */
59 if (frozen(p)) { 53extern int thaw_process(struct task_struct *p);
60 p->flags &= ~PF_FROZEN;
61 task_unlock(p);
62 wake_up_process(p);
63 return 1;
64 }
65 clear_freeze_flag(p);
66 task_unlock(p);
67 return 0;
68}
69 54
70extern void refrigerator(void); 55extern void refrigerator(void);
71extern int freeze_processes(void); 56extern int freeze_processes(void);
@@ -83,6 +68,12 @@ static inline int try_to_freeze(void)
83extern bool freeze_task(struct task_struct *p, bool sig_only); 68extern bool freeze_task(struct task_struct *p, bool sig_only);
84extern void cancel_freezing(struct task_struct *p); 69extern void cancel_freezing(struct task_struct *p);
85 70
71#ifdef CONFIG_CGROUP_FREEZER
72extern int cgroup_frozen(struct task_struct *task);
73#else /* !CONFIG_CGROUP_FREEZER */
74static inline int cgroup_frozen(struct task_struct *task) { return 0; }
75#endif /* !CONFIG_CGROUP_FREEZER */
76
86/* 77/*
87 * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it 78 * The PF_FREEZER_SKIP flag should be set by a vfork parent right before it
88 * calls wait_for_completion(&vfork) and reset right after it returns from this 79 * calls wait_for_completion(&vfork) and reset right after it returns from this
diff --git a/init/Kconfig b/init/Kconfig
index 5ceff3249a2d..8828ed0b2051 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -299,6 +299,13 @@ config CGROUP_NS
299 for instance virtual servers and checkpoint/restart 299 for instance virtual servers and checkpoint/restart
300 jobs. 300 jobs.
301 301
302config CGROUP_FREEZER
303 bool "control group freezer subsystem"
304 depends on CGROUPS
305 help
306 Provides a way to freeze and unfreeze all tasks in a
307 cgroup.
308
302config CGROUP_DEVICE 309config CGROUP_DEVICE
303 bool "Device controller for cgroups" 310 bool "Device controller for cgroups"
304 depends on CGROUPS && EXPERIMENTAL 311 depends on CGROUPS && EXPERIMENTAL
diff --git a/kernel/Kconfig.freezer b/kernel/Kconfig.freezer
new file mode 100644
index 000000000000..a3bb4cb52539
--- /dev/null
+++ b/kernel/Kconfig.freezer
@@ -0,0 +1,2 @@
1config FREEZER
2 def_bool PM_SLEEP || CGROUP_FREEZER
diff --git a/kernel/Makefile b/kernel/Makefile
index e8194d15d5f4..066550aa61c5 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
56obj-$(CONFIG_COMPAT) += compat.o 56obj-$(CONFIG_COMPAT) += compat.o
57obj-$(CONFIG_CGROUPS) += cgroup.o 57obj-$(CONFIG_CGROUPS) += cgroup.o
58obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o 58obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o
59obj-$(CONFIG_CGROUP_FREEZER) += cgroup_freezer.o
59obj-$(CONFIG_CPUSETS) += cpuset.o 60obj-$(CONFIG_CPUSETS) += cpuset.o
60obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o 61obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o
61obj-$(CONFIG_UTS_NS) += utsname.o 62obj-$(CONFIG_UTS_NS) += utsname.o
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
new file mode 100644
index 000000000000..b08722de610c
--- /dev/null
+++ b/kernel/cgroup_freezer.c
@@ -0,0 +1,366 @@
1/*
2 * cgroup_freezer.c - control group freezer subsystem
3 *
4 * Copyright IBM Corporation, 2007
5 *
6 * Author : Cedric Le Goater <clg@fr.ibm.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of version 2.1 of the GNU Lesser General Public License
10 * as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it would be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
15 */
16
17#include <linux/module.h>
18#include <linux/cgroup.h>
19#include <linux/fs.h>
20#include <linux/uaccess.h>
21#include <linux/freezer.h>
22#include <linux/seq_file.h>
23
24enum freezer_state {
25 STATE_RUNNING = 0,
26 STATE_FREEZING,
27 STATE_FROZEN,
28};
29
30struct freezer {
31 struct cgroup_subsys_state css;
32 enum freezer_state state;
33 spinlock_t lock; /* protects _writes_ to state */
34};
35
36static inline struct freezer *cgroup_freezer(
37 struct cgroup *cgroup)
38{
39 return container_of(
40 cgroup_subsys_state(cgroup, freezer_subsys_id),
41 struct freezer, css);
42}
43
44static inline struct freezer *task_freezer(struct task_struct *task)
45{
46 return container_of(task_subsys_state(task, freezer_subsys_id),
47 struct freezer, css);
48}
49
50int cgroup_frozen(struct task_struct *task)
51{
52 struct freezer *freezer;
53 enum freezer_state state;
54
55 task_lock(task);
56 freezer = task_freezer(task);
57 state = freezer->state;
58 task_unlock(task);
59
60 return state == STATE_FROZEN;
61}
62
63/*
64 * cgroups_write_string() limits the size of freezer state strings to
65 * CGROUP_LOCAL_BUFFER_SIZE
66 */
67static const char *freezer_state_strs[] = {
68 "RUNNING",
69 "FREEZING",
70 "FROZEN",
71};
72
73/*
74 * State diagram
75 * Transitions are caused by userspace writes to the freezer.state file.
76 * The values in parenthesis are state labels. The rest are edge labels.
77 *
78 * (RUNNING) --FROZEN--> (FREEZING) --FROZEN--> (FROZEN)
79 * ^ ^ | |
80 * | \_______RUNNING_______/ |
81 * \_____________________________RUNNING___________/
82 */
83
84struct cgroup_subsys freezer_subsys;
85
86/* Locks taken and their ordering
87 * ------------------------------
88 * css_set_lock
89 * cgroup_mutex (AKA cgroup_lock)
90 * task->alloc_lock (AKA task_lock)
91 * freezer->lock
92 * task->sighand->siglock
93 *
94 * cgroup code forces css_set_lock to be taken before task->alloc_lock
95 *
96 * freezer_create(), freezer_destroy():
97 * cgroup_mutex [ by cgroup core ]
98 *
99 * can_attach():
100 * cgroup_mutex
101 *
102 * cgroup_frozen():
103 * task->alloc_lock (to get task's cgroup)
104 *
105 * freezer_fork() (preserving fork() performance means can't take cgroup_mutex):
106 * task->alloc_lock (to get task's cgroup)
107 * freezer->lock
108 * sighand->siglock (if the cgroup is freezing)
109 *
110 * freezer_read():
111 * cgroup_mutex
112 * freezer->lock
113 * read_lock css_set_lock (cgroup iterator start)
114 *
115 * freezer_write() (freeze):
116 * cgroup_mutex
117 * freezer->lock
118 * read_lock css_set_lock (cgroup iterator start)
119 * sighand->siglock
120 *
121 * freezer_write() (unfreeze):
122 * cgroup_mutex
123 * freezer->lock
124 * read_lock css_set_lock (cgroup iterator start)
125 * task->alloc_lock (to prevent races with freeze_task())
126 * sighand->siglock
127 */
128static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
129 struct cgroup *cgroup)
130{
131 struct freezer *freezer;
132
133 freezer = kzalloc(sizeof(struct freezer), GFP_KERNEL);
134 if (!freezer)
135 return ERR_PTR(-ENOMEM);
136
137 spin_lock_init(&freezer->lock);
138 freezer->state = STATE_RUNNING;
139 return &freezer->css;
140}
141
142static void freezer_destroy(struct cgroup_subsys *ss,
143 struct cgroup *cgroup)
144{
145 kfree(cgroup_freezer(cgroup));
146}
147
148
149static int freezer_can_attach(struct cgroup_subsys *ss,
150 struct cgroup *new_cgroup,
151 struct task_struct *task)
152{
153 struct freezer *freezer;
154 int retval = 0;
155
156 /*
157 * The call to cgroup_lock() in the freezer.state write method prevents
158 * a write to that file racing against an attach, and hence the
159 * can_attach() result will remain valid until the attach completes.
160 */
161 freezer = cgroup_freezer(new_cgroup);
162 if (freezer->state == STATE_FROZEN)
163 retval = -EBUSY;
164 return retval;
165}
166
167static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
168{
169 struct freezer *freezer;
170
171 task_lock(task);
172 freezer = task_freezer(task);
173 task_unlock(task);
174
175 BUG_ON(freezer->state == STATE_FROZEN);
176 spin_lock_irq(&freezer->lock);
177 /* Locking avoids race with FREEZING -> RUNNING transitions. */
178 if (freezer->state == STATE_FREEZING)
179 freeze_task(task, true);
180 spin_unlock_irq(&freezer->lock);
181}
182
183/*
184 * caller must hold freezer->lock
185 */
186static void check_if_frozen(struct cgroup *cgroup,
187 struct freezer *freezer)
188{
189 struct cgroup_iter it;
190 struct task_struct *task;
191 unsigned int nfrozen = 0, ntotal = 0;
192
193 cgroup_iter_start(cgroup, &it);
194 while ((task = cgroup_iter_next(cgroup, &it))) {
195 ntotal++;
196 /*
197 * Task is frozen or will freeze immediately when next it gets
198 * woken
199 */
200 if (frozen(task) ||
201 (task_is_stopped_or_traced(task) && freezing(task)))
202 nfrozen++;
203 }
204
205 /*
206 * Transition to FROZEN when no new tasks can be added ensures
207 * that we never exist in the FROZEN state while there are unfrozen
208 * tasks.
209 */
210 if (nfrozen == ntotal)
211 freezer->state = STATE_FROZEN;
212 cgroup_iter_end(cgroup, &it);
213}
214
215static int freezer_read(struct cgroup *cgroup, struct cftype *cft,
216 struct seq_file *m)
217{
218 struct freezer *freezer;
219 enum freezer_state state;
220
221 if (!cgroup_lock_live_group(cgroup))
222 return -ENODEV;
223
224 freezer = cgroup_freezer(cgroup);
225 spin_lock_irq(&freezer->lock);
226 state = freezer->state;
227 if (state == STATE_FREEZING) {
228 /* We change from FREEZING to FROZEN lazily if the cgroup was
229 * only partially frozen when we exitted write. */
230 check_if_frozen(cgroup, freezer);
231 state = freezer->state;
232 }
233 spin_unlock_irq(&freezer->lock);
234 cgroup_unlock();
235
236 seq_puts(m, freezer_state_strs[state]);
237 seq_putc(m, '\n');
238 return 0;
239}
240
241static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
242{
243 struct cgroup_iter it;
244 struct task_struct *task;
245 unsigned int num_cant_freeze_now = 0;
246
247 freezer->state = STATE_FREEZING;
248 cgroup_iter_start(cgroup, &it);
249 while ((task = cgroup_iter_next(cgroup, &it))) {
250 if (!freeze_task(task, true))
251 continue;
252 if (task_is_stopped_or_traced(task) && freezing(task))
253 /*
254 * The freeze flag is set so these tasks will
255 * immediately go into the fridge upon waking.
256 */
257 continue;
258 if (!freezing(task) && !freezer_should_skip(task))
259 num_cant_freeze_now++;
260 }
261 cgroup_iter_end(cgroup, &it);
262
263 return num_cant_freeze_now ? -EBUSY : 0;
264}
265
266static int unfreeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
267{
268 struct cgroup_iter it;
269 struct task_struct *task;
270
271 cgroup_iter_start(cgroup, &it);
272 while ((task = cgroup_iter_next(cgroup, &it))) {
273 int do_wake;
274
275 task_lock(task);
276 do_wake = __thaw_process(task);
277 task_unlock(task);
278 if (do_wake)
279 wake_up_process(task);
280 }
281 cgroup_iter_end(cgroup, &it);
282 freezer->state = STATE_RUNNING;
283
284 return 0;
285}
286
287static int freezer_change_state(struct cgroup *cgroup,
288 enum freezer_state goal_state)
289{
290 struct freezer *freezer;
291 int retval = 0;
292
293 freezer = cgroup_freezer(cgroup);
294 spin_lock_irq(&freezer->lock);
295 check_if_frozen(cgroup, freezer); /* may update freezer->state */
296 if (goal_state == freezer->state)
297 goto out;
298 switch (freezer->state) {
299 case STATE_RUNNING:
300 retval = try_to_freeze_cgroup(cgroup, freezer);
301 break;
302 case STATE_FREEZING:
303 if (goal_state == STATE_FROZEN) {
304 /* Userspace is retrying after
305 * "/bin/echo FROZEN > freezer.state" returned -EBUSY */
306 retval = try_to_freeze_cgroup(cgroup, freezer);
307 break;
308 }
309 /* state == FREEZING and goal_state == RUNNING, so unfreeze */
310 case STATE_FROZEN:
311 retval = unfreeze_cgroup(cgroup, freezer);
312 break;
313 default:
314 break;
315 }
316out:
317 spin_unlock_irq(&freezer->lock);
318
319 return retval;
320}
321
322static int freezer_write(struct cgroup *cgroup,
323 struct cftype *cft,
324 const char *buffer)
325{
326 int retval;
327 enum freezer_state goal_state;
328
329 if (strcmp(buffer, freezer_state_strs[STATE_RUNNING]) == 0)
330 goal_state = STATE_RUNNING;
331 else if (strcmp(buffer, freezer_state_strs[STATE_FROZEN]) == 0)
332 goal_state = STATE_FROZEN;
333 else
334 return -EIO;
335
336 if (!cgroup_lock_live_group(cgroup))
337 return -ENODEV;
338 retval = freezer_change_state(cgroup, goal_state);
339 cgroup_unlock();
340 return retval;
341}
342
343static struct cftype files[] = {
344 {
345 .name = "state",
346 .read_seq_string = freezer_read,
347 .write_string = freezer_write,
348 },
349};
350
351static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
352{
353 return cgroup_add_files(cgroup, ss, files, ARRAY_SIZE(files));
354}
355
356struct cgroup_subsys freezer_subsys = {
357 .name = "freezer",
358 .create = freezer_create,
359 .destroy = freezer_destroy,
360 .populate = freezer_populate,
361 .subsys_id = freezer_subsys_id,
362 .can_attach = freezer_can_attach,
363 .attach = NULL,
364 .fork = freezer_fork,
365 .exit = NULL,
366};
diff --git a/kernel/freezer.c b/kernel/freezer.c
index cb0931f89306..ba6248b323ef 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -120,3 +120,35 @@ void cancel_freezing(struct task_struct *p)
120 spin_unlock_irqrestore(&p->sighand->siglock, flags); 120 spin_unlock_irqrestore(&p->sighand->siglock, flags);
121 } 121 }
122} 122}
123
124/*
125 * Wake up a frozen process
126 *
127 * task_lock() is needed to prevent the race with refrigerator() which may
128 * occur if the freezing of tasks fails. Namely, without the lock, if the
129 * freezing of tasks failed, thaw_tasks() might have run before a task in
130 * refrigerator() could call frozen_process(), in which case the task would be
131 * frozen and no one would thaw it.
132 */
133int __thaw_process(struct task_struct *p)
134{
135 if (frozen(p)) {
136 p->flags &= ~PF_FROZEN;
137 return 1;
138 }
139 clear_freeze_flag(p);
140 return 0;
141}
142
143int thaw_process(struct task_struct *p)
144{
145 task_lock(p);
146 if (__thaw_process(p) == 1) {
147 task_unlock(p);
148 wake_up_process(p);
149 return 1;
150 }
151 task_unlock(p);
152 return 0;
153}
154EXPORT_SYMBOL(thaw_process);
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index ebdd7f55273d..dcd165f92a88 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -85,9 +85,6 @@ config PM_SLEEP
85 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE 85 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
86 default y 86 default y
87 87
88config FREEZER
89 def_bool PM_SLEEP
90
91config SUSPEND 88config SUSPEND
92 bool "Suspend to RAM and standby" 89 bool "Suspend to RAM and standby"
93 depends on PM && ARCH_SUSPEND_POSSIBLE 90 depends on PM && ARCH_SUSPEND_POSSIBLE
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-07 14:42:46 -0500