The patch titled
Disable CPU hotplug during suspend
has been removed from the -mm tree. Its filename is
disable-cpu-hotplug-during-suspend.patch
This patch was dropped because an updated version was merged
------------------------------------------------------
Subject: Disable CPU hotplug during suspend
From: "Rafael J. Wysocki" <rjw@xxxxxxx>
The current suspend code has to be run on one CPU, so we use the CPU
hotplug to take the non-boot CPUs offline on SMP machines. However, we
should also make sure that these CPUs will not be enabled by someone else
after we have disabled them.
The functions disable_nonboot_cpus() and enable_nonboot_cpus() are moved to
kernel/cpu.c, because they now refer to some stuff in there that should
better be static. Also it's better if disable_nonboot_cpus() returns an
error instead of panicking if something goes wrong, and
enable_nonboot_cpus() has no reason to panic(), because the CPUs may have
been enabled by the userland before it tries to take them online.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/cpu.h | 8 ++
include/linux/suspend.h | 8 --
kernel/cpu.c | 104 +++++++++++++++++++++++++++++++++-----
kernel/power/Makefile | 2
kernel/power/disk.c | 7 ++
kernel/power/main.c | 10 +--
kernel/power/smp.c | 62 ----------------------
kernel/power/user.c | 14 +++--
8 files changed, 118 insertions(+), 97 deletions(-)
diff -puN include/linux/cpu.h~disable-cpu-hotplug-during-suspend include/linux/cpu.h
--- a/include/linux/cpu.h~disable-cpu-hotplug-during-suspend
+++ a/include/linux/cpu.h
@@ -89,4 +89,12 @@ int cpu_down(unsigned int cpu);
static inline int cpu_is_offline(int cpu) { return 0; }
#endif
+#ifdef CONFIG_SUSPEND_SMP
+extern int disable_nonboot_cpus(void);
+extern void enable_nonboot_cpus(void);
+#else
+static inline int disable_nonboot_cpus(void) { return 0; }
+static inline void enable_nonboot_cpus(void) {}
+#endif
+
#endif /* _LINUX_CPU_H_ */
diff -puN include/linux/suspend.h~disable-cpu-hotplug-during-suspend include/linux/suspend.h
--- a/include/linux/suspend.h~disable-cpu-hotplug-during-suspend
+++ a/include/linux/suspend.h
@@ -57,14 +57,6 @@ static inline int software_suspend(void)
}
#endif /* CONFIG_PM */
-#ifdef CONFIG_SUSPEND_SMP
-extern void disable_nonboot_cpus(void);
-extern void enable_nonboot_cpus(void);
-#else
-static inline void disable_nonboot_cpus(void) {}
-static inline void enable_nonboot_cpus(void) {}
-#endif
-
void save_processor_state(void);
void restore_processor_state(void);
struct saved_context;
diff -puN kernel/cpu.c~disable-cpu-hotplug-during-suspend kernel/cpu.c
--- a/kernel/cpu.c~disable-cpu-hotplug-during-suspend
+++ a/kernel/cpu.c
@@ -21,6 +21,11 @@ static DEFINE_MUTEX(cpu_bitmask_lock);
static __cpuinitdata BLOCKING_NOTIFIER_HEAD(cpu_chain);
+/* If set, cpu_up and cpu_down will return -EPERM and do nothing.
+ * Should always be manipulated under cpu_add_remove_lock
+ */
+static int cpu_hotplug_disabled;
+
#ifdef CONFIG_HOTPLUG_CPU
/* Crappy recursive lock-takers in cpufreq! Complain loudly about idiots */
@@ -108,30 +113,25 @@ static int take_cpu_down(void *unused)
return 0;
}
-int cpu_down(unsigned int cpu)
+/* Requires cpu_add_remove_lock to be held */
+static int __cpu_down(unsigned int cpu)
{
int err;
struct task_struct *p;
cpumask_t old_allowed, tmp;
- mutex_lock(&cpu_add_remove_lock);
- if (num_online_cpus() == 1) {
- err = -EBUSY;
- goto out;
- }
+ if (num_online_cpus() == 1)
+ return -EBUSY;
- if (!cpu_online(cpu)) {
- err = -EINVAL;
- goto out;
- }
+ if (!cpu_online(cpu))
+ return -EINVAL;
err = blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
(void *)(long)cpu);
if (err == NOTIFY_BAD) {
printk("%s: attempt to take down CPU %u failed\n",
__FUNCTION__, cpu);
- err = -EINVAL;
- goto out;
+ return -EINVAL;
}
/* Ensure that we are not runnable on dying cpu */
@@ -179,7 +179,19 @@ out_thread:
err = kthread_stop(p);
out_allowed:
set_cpus_allowed(current, old_allowed);
-out:
+ return err;
+}
+
+int cpu_down(unsigned int cpu)
+{
+ int err = 0;
+
+ mutex_lock(&cpu_add_remove_lock);
+ if (cpu_hotplug_disabled)
+ err = -EPERM;
+ else
+ err = __cpu_down(cpu);
+
mutex_unlock(&cpu_add_remove_lock);
return err;
}
@@ -191,6 +203,11 @@ int __devinit cpu_up(unsigned int cpu)
void *hcpu = (void *)(long)cpu;
mutex_lock(&cpu_add_remove_lock);
+ if (cpu_hotplug_disabled) {
+ ret = -EPERM;
+ goto out;
+ }
+
if (cpu_online(cpu) || !cpu_present(cpu)) {
ret = -EINVAL;
goto out;
@@ -223,3 +240,64 @@ out:
mutex_unlock(&cpu_add_remove_lock);
return ret;
}
+
+#ifdef CONFIG_SUSPEND_SMP
+static cpumask_t frozen_cpus;
+
+int disable_nonboot_cpus(void)
+{
+ int cpu, error = 0;
+
+ /* We take all of the non-boot CPUs down in one shot to avoid races
+ * with the userspace trying to use the CPU hotplug at the same time
+ */
+ mutex_lock(&cpu_add_remove_lock);
+ cpus_clear(frozen_cpus);
+ printk("Disabling non-boot CPUs ...\n");
+ for_each_online_cpu(cpu) {
+ if (cpu == 0)
+ continue;
+ error = __cpu_down(cpu);
+ if (!error) {
+ cpu_set(cpu, frozen_cpus);
+ printk("CPU%d is down\n", cpu);
+ } else {
+ printk(KERN_ERR "Error taking CPU%d down: %d\n",
+ cpu, error);
+ break;
+ }
+ }
+ if (!error) {
+ BUG_ON(num_online_cpus() > 1);
+ BUG_ON(raw_smp_processor_id() != 0);
+ /* Make sure the CPUs won't be enabled by someone else */
+ cpu_hotplug_disabled = 1;
+ } else {
+ printk(KERN_ERR "Non-boot CPUs are not disabled");
+ }
+ mutex_unlock(&cpu_add_remove_lock);
+ return error;
+}
+
+void enable_nonboot_cpus(void)
+{
+ int cpu, error;
+
+ /* Allow everyone to use the CPU hotplug again */
+ mutex_lock(&cpu_add_remove_lock);
+ cpu_hotplug_disabled = 0;
+ mutex_unlock(&cpu_add_remove_lock);
+
+ printk("Enabling non-boot CPUs ...\n");
+ for_each_cpu_mask(cpu, frozen_cpus) {
+ error = cpu_up(cpu);
+ if (!error) {
+ printk("CPU%d is up\n", cpu);
+ continue;
+ }
+ printk(KERN_WARNING "Error taking CPU%d up: %d\n",
+ cpu, error);
+ }
+ cpus_clear(frozen_cpus);
+}
+#endif
diff -puN kernel/power/disk.c~disable-cpu-hotplug-during-suspend kernel/power/disk.c
--- a/kernel/power/disk.c~disable-cpu-hotplug-during-suspend
+++ a/kernel/power/disk.c
@@ -18,6 +18,7 @@
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pm.h>
+#include <linux/cpu.h>
#include "power.h"
@@ -72,7 +73,10 @@ static int prepare_processes(void)
int error;
pm_prepare_console();
- disable_nonboot_cpus();
+
+ error = disable_nonboot_cpus();
+ if (error)
+ goto enable_cpus;
if (freeze_processes()) {
error = -EBUSY;
@@ -84,6 +88,7 @@ static int prepare_processes(void)
return 0;
thaw:
thaw_processes();
+enable_cpus:
enable_nonboot_cpus();
pm_restore_console();
return error;
diff -puN kernel/power/main.c~disable-cpu-hotplug-during-suspend kernel/power/main.c
--- a/kernel/power/main.c~disable-cpu-hotplug-during-suspend
+++ a/kernel/power/main.c
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/console.h>
+#include <linux/cpu.h>
#include "power.h"
@@ -51,7 +52,7 @@ void pm_set_ops(struct pm_ops * ops)
static int suspend_prepare(suspend_state_t state)
{
- int error = 0;
+ int error;
unsigned int free_pages;
if (!pm_ops || !pm_ops->enter)
@@ -63,12 +64,9 @@ static int suspend_prepare(suspend_state
pm_prepare_console();
- disable_nonboot_cpus();
-
- if (num_online_cpus() != 1) {
- error = -EPERM;
+ error = disable_nonboot_cpus();
+ if (error)
goto Enable_cpu;
- }
if (freeze_processes()) {
error = -EAGAIN;
diff -puN kernel/power/Makefile~disable-cpu-hotplug-during-suspend kernel/power/Makefile
--- a/kernel/power/Makefile~disable-cpu-hotplug-during-suspend
+++ a/kernel/power/Makefile
@@ -7,6 +7,4 @@ obj-y := main.o process.o console.o
obj-$(CONFIG_PM_LEGACY) += pm.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o user.o
-obj-$(CONFIG_SUSPEND_SMP) += smp.o
-
obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
diff -puN kernel/power/smp.c~disable-cpu-hotplug-during-suspend /dev/null
--- a/kernel/power/smp.c
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * drivers/power/smp.c - Functions for stopping other CPUs.
- *
- * Copyright 2004 Pavel Machek <pavel@xxxxxxx>
- * Copyright (C) 2002-2003 Nigel Cunningham <ncunningham@xxxxxxxxxxxx>
- *
- * This file is released under the GPLv2.
- */
-
-#undef DEBUG
-
-#include <linux/smp_lock.h>
-#include <linux/interrupt.h>
-#include <linux/suspend.h>
-#include <linux/module.h>
-#include <linux/cpu.h>
-#include <asm/atomic.h>
-#include <asm/tlbflush.h>
-
-/* This is protected by pm_sem semaphore */
-static cpumask_t frozen_cpus;
-
-void disable_nonboot_cpus(void)
-{
- int cpu, error;
-
- error = 0;
- cpus_clear(frozen_cpus);
- printk("Freezing cpus ...\n");
- for_each_online_cpu(cpu) {
- if (cpu == 0)
- continue;
- error = cpu_down(cpu);
- if (!error) {
- cpu_set(cpu, frozen_cpus);
- printk("CPU%d is down\n", cpu);
- continue;
- }
- printk("Error taking cpu %d down: %d\n", cpu, error);
- }
- BUG_ON(raw_smp_processor_id() != 0);
- if (error)
- panic("cpus not sleeping");
-}
-
-void enable_nonboot_cpus(void)
-{
- int cpu, error;
-
- printk("Thawing cpus ...\n");
- for_each_cpu_mask(cpu, frozen_cpus) {
- error = cpu_up(cpu);
- if (!error) {
- printk("CPU%d is up\n", cpu);
- continue;
- }
- printk("Error taking cpu %d up: %d\n", cpu, error);
- panic("Not enough cpus");
- }
- cpus_clear(frozen_cpus);
-}
-
diff -puN kernel/power/user.c~disable-cpu-hotplug-during-suspend kernel/power/user.c
--- a/kernel/power/user.c~disable-cpu-hotplug-during-suspend
+++ a/kernel/power/user.c
@@ -19,6 +19,7 @@
#include <linux/swapops.h>
#include <linux/pm.h>
#include <linux/fs.h>
+#include <linux/cpu.h>
#include <asm/uaccess.h>
@@ -139,12 +140,15 @@ static int snapshot_ioctl(struct inode *
if (data->frozen)
break;
down(&pm_sem);
- disable_nonboot_cpus();
- if (freeze_processes()) {
- thaw_processes();
- enable_nonboot_cpus();
- error = -EBUSY;
+ error = disable_nonboot_cpus();
+ if (!error) {
+ error = freeze_processes();
+ if (error) {
+ thaw_processes();
+ error = -EBUSY;
+ }
}
+ enable_nonboot_cpus();
up(&pm_sem);
if (!error)
data->frozen = 1;
_
Patches currently in -mm which might be from rjw@xxxxxxx are
pm-define-pm_event_prethaw.patch
pm-pci-and-ide-handle-pm_event_prethaw.patch
pm-video-drivers-and-pm_event_prethaw.patch
pm-usb-hcds-use-pm_event_prethaw.patch
pm-usb-hcds-use-pm_event_prethaw-fix.patch
pm-issue-pm_event_prethaw.patch
swsusp-write-timer.patch
swsusp-write-speedup.patch
swsusp-read-timer.patch
swsusp-read-speedup.patch
swsusp-read-speedup-fix.patch
swsusp-read-speedup-cleanup.patch
swsusp-read-speedup-cleanup-2.patch
swsusp-clean-up-browsing-of-pfns.patch
swsusp-struct-snapshot_handle-cleanup.patch
make-swsusp-avoid-memory-holes-and-reserved-memory-regions-on-x86_64.patch
make-suspend-possible-with-a-traced-process-at-a-breakpoint.patch
allow-cifsd-to-suspend-if-connection-is-lost.patch
disable-cpu-hotplug-during-suspend.patch
fix-swsusp-with-pnp-bios.patch
-
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