--- /dev/null
+Freezing of tasks
+ (C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL
+
+I. What is the freezing of tasks?
+
+The freezing of tasks is a mechanism by which user space processes and some
+kernel threads are controlled during hibernation or system-wide suspend (on some
+architectures).
+
+II. How does it work?
+
+There are four per-task flags used for that, PF_NOFREEZE, PF_FROZEN, TIF_FREEZE
+and PF_FREEZER_SKIP (the last one is auxiliary). The tasks that have
+PF_NOFREEZE unset (all user space processes and some kernel threads) are
+regarded as 'freezable' and treated in a special way before the system enters a
+suspend state as well as before a hibernation image is created (in what follows
+we only consider hibernation, but the description also applies to suspend).
+
+Namely, as the first step of the hibernation procedure the function
+freeze_processes() (defined in kernel/power/process.c) is called. It executes
+try_to_freeze_tasks() that sets TIF_FREEZE for all of the freezable tasks and
+sends a fake signal to each of them. A task that receives such a signal and has
+TIF_FREEZE set, should react to it by calling the refrigerator() function
+(defined in kernel/power/process.c), which sets the task's PF_FROZEN flag,
+changes its state to TASK_UNINTERRUPTIBLE and makes it loop until PF_FROZEN is
+cleared for it. Then, we say that the task is 'frozen' and therefore the set of
+functions handling this mechanism is called 'the freezer' (these functions are
+defined in kernel/power/process.c and include/linux/freezer.h). User space
+processes are generally frozen before kernel threads.
+
+It is not recommended to call refrigerator() directly. Instead, it is
+recommended to use the try_to_freeze() function (defined in
+include/linux/freezer.h), that checks the task's TIF_FREEZE flag and makes the
+task enter refrigerator() if the flag is set.
+
+For user space processes try_to_freeze() is called automatically from the
+signal-handling code, but the freezable kernel threads need to call it
+explicitly in suitable places. The code to do this may look like the following:
+
+ do {
+ hub_events();
+ wait_event_interruptible(khubd_wait,
+ !list_empty(&hub_event_list));
+ try_to_freeze();
+ } while (!signal_pending(current));
+
+(from drivers/usb/core/hub.c::hub_thread()).
+
+If a freezable kernel thread fails to call try_to_freeze() after the freezer has
+set TIF_FREEZE for it, the freezing of tasks will fail and the entire
+hibernation operation will be cancelled. For this reason, freezable kernel
+threads must call try_to_freeze() somewhere.
+
+After the system memory state has been restored from a hibernation image and
+devices have been reinitialized, the function thaw_processes() is called in
+order to clear the PF_FROZEN flag for each frozen task. Then, the tasks that
+have been frozen leave refrigerator() and continue running.
+
+III. Which kernel threads are freezable?
+
+Kernel threads are not freezable by default. However, a kernel thread may clear
+PF_NOFREEZE for itself by calling set_freezable() (the resetting of PF_NOFREEZE
+directly is strongly discouraged). From this point it is regarded as freezable
+and must call try_to_freeze() in a suitable place.
+
+IV. Why do we do that?
+
+Generally speaking, there is a couple of reasons to use the freezing of tasks:
+
+1. The principal reason is to prevent filesystems from being damaged after
+hibernation. At the moment we have no simple means of checkpointing
+filesystems, so if there are any modifications made to filesystem data and/or
+metadata on disks, we cannot bring them back to the state from before the
+modifications. At the same time each hibernation image contains some
+filesystem-related information that must be consistent with the state of the
+on-disk data and metadata after the system memory state has been restored from
+the image (otherwise the filesystems will be damaged in a nasty way, usually
+making them almost impossible to repair). We therefore freeze tasks that might
+cause the on-disk filesystems' data and metadata to be modified after the
+hibernation image has been created and before the system is finally powered off.
+The majority of these are user space processes, but if any of the kernel threads
+may cause something like this to happen, they have to be freezable.
+
+2. The second reason is to prevent user space processes and some kernel threads
+from interfering with the suspending and resuming of devices. A user space
+process running on a second CPU while we are suspending devices may, for
+example, be troublesome and without the freezing of tasks we would need some
+safeguards against race conditions that might occur in such a case.
+
+Although Linus Torvalds doesn't like the freezing of tasks, he said this in one
+of the discussions on LKML (http://lkml.org/lkml/2007/4/27/608):
+
+"RJW:> Why we freeze tasks at all or why we freeze kernel threads?
+
+Linus: In many ways, 'at all'.
+
+I _do_ realize the IO request queue issues, and that we cannot actually do
+s2ram with some devices in the middle of a DMA. So we want to be able to
+avoid *that*, there's no question about that. And I suspect that stopping
+user threads and then waiting for a sync is practically one of the easier
+ways to do so.
+
+So in practice, the 'at all' may become a 'why freeze kernel threads?' and
+freezing user threads I don't find really objectionable."
+
+Still, there are kernel threads that may want to be freezable. For example, if
+a kernel that belongs to a device driver accesses the device directly, it in
+principle needs to know when the device is suspended, so that it doesn't try to
+access it at that time. However, if the kernel thread is freezable, it will be
+frozen before the driver's .suspend() callback is executed and it will be
+thawed after the driver's .resume() callback has run, so it won't be accessing
+the device while it's suspended.
+
+3. Another reason for freezing tasks is to prevent user space processes from
+realizing that hibernation (or suspend) operation takes place. Ideally, user
+space processes should not notice that such a system-wide operation has occurred
+and should continue running without any problems after the restore (or resume
+from suspend). Unfortunately, in the most general case this is quite difficult
+to achieve without the freezing of tasks. Consider, for example, a process
+that depends on all CPUs being online while it's running. Since we need to
+disable nonboot CPUs during the hibernation, if this process is not frozen, it
+may notice that the number of CPUs has changed and may start to work incorrectly
+because of that.
+
+V. Are there any problems related to the freezing of tasks?
+
+Yes, there are.
+
+First of all, the freezing of kernel threads may be tricky if they depend one
+on another. For example, if kernel thread A waits for a completion (in the
+TASK_UNINTERRUPTIBLE state) that needs to be done by freezable kernel thread B
+and B is frozen in the meantime, then A will be blocked until B is thawed, which
+may be undesirable. That's why kernel threads are not freezable by default.
+
+Second, there are the following two problems related to the freezing of user
+space processes:
+1. Putting processes into an uninterruptible sleep distorts the load average.
+2. Now that we have FUSE, plus the framework for doing device drivers in
+userspace, it gets even more complicated because some userspace processes are
+now doing the sorts of things that kernel threads do
+(https://lists.linux-foundation.org/pipermail/linux-pm/2007-May/012309.html).
+
+The problem 1. seems to be fixable, although it hasn't been fixed so far. The
+other one is more serious, but it seems that we can work around it by using
+hibernation (and suspend) notifiers (in that case, though, we won't be able to
+avoid the realization by the user space processes that the hibernation is taking
+place).
+
+There are also problems that the freezing of tasks tends to expose, although
+they are not directly related to it. For example, if request_firmware() is
+called from a device driver's .resume() routine, it will timeout and eventually
+fail, because the user land process that should respond to the request is frozen
+at this point. So, seemingly, the failure is due to the freezing of tasks.
+Suppose, however, that the firmware file is located on a filesystem accessible
+only through another device that hasn't been resumed yet. In that case,
+request_firmware() will fail regardless of whether or not the freezing of tasks
+is used. Consequently, the problem is not really related to the freezing of
+tasks, since it generally exists anyway. [The solution to this particular
+problem is to keep the firmware in memory after it's loaded for the first time
+and upload if from memory to the device whenever necessary.]
+++ /dev/null
-KERNEL THREADS
-
-
-Freezer
-
-Upon entering a suspended state the system will freeze all
-tasks. This is done by delivering pseudosignals. This affects
-kernel threads, too. To successfully freeze a kernel thread
-the thread has to check for the pseudosignal and enter the
-refrigerator. Code to do this looks like this:
-
- do {
- hub_events();
- wait_event_interruptible(khubd_wait, !list_empty(&hub_event_list));
- try_to_freeze();
- } while (!signal_pending(current));
-
-from drivers/usb/core/hub.c::hub_thread()
-
-
-The Unfreezable
-
-Some kernel threads however, must not be frozen. The kernel must
-be able to finish pending IO operations and later on be able to
-write the memory image to disk. Kernel threads needed to do IO
-must stay awake. Such threads must mark themselves unfreezable
-like this:
-
- /*
- * This thread doesn't need any user-level access,
- * so get rid of all our resources.
- */
- daemonize("usb-storage");
-
- current->flags |= PF_NOFREEZE;
-
-from drivers/usb/storage/usb.c::usb_stor_control_thread()
-
-Such drivers are themselves responsible for staying quiet during
-the actual snapshotting.
website, and not to the Linux Kernel Mailing List. We are working
toward merging suspend2 into the mainline kernel.
-Q: A kernel thread must voluntarily freeze itself (call 'refrigerator').
-I found some kernel threads that don't do it, and they don't freeze
-so the system can't sleep. Is this a known behavior?
-
-A: All such kernel threads need to be fixed, one by one. Select the
-place where the thread is safe to be frozen (no kernel semaphores
-should be held at that point and it must be safe to sleep there), and
-add:
-
- try_to_freeze();
-
-If the thread is needed for writing the image to storage, you should
-instead set the PF_NOFREEZE process flag when creating the thread (and
-be very careful).
+Q: What is the freezing of tasks and why are we using it?
+A: The freezing of tasks is a mechanism by which user space processes and some
+kernel threads are controlled during hibernation or system-wide suspend (on some
+architectures). See freezing-of-tasks.txt for details.
Q: What is the difference between "platform" and "shutdown"?
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/kernel.h>
+#include <linux/freezer.h>
#include <linux/smp.h>
#include <linux/dmi.h>
#include <linux/suspend.h>
remove_proc_entry("apm", NULL);
return err;
}
- kapmd_task->flags |= PF_NOFREEZE;
wake_up_process(kapmd_task);
if (num_online_cpus() > 1 && !smp ) {
set_pending_irq(i, cpumask_of_cpu(0));
}
+ set_freezable();
for ( ; ; ) {
time_remaining = schedule_timeout_interruptible(time_remaining);
try_to_freeze();
#include <linux/loop.h>
#include <linux/compat.h>
#include <linux/suspend.h>
+#include <linux/freezer.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* for invalidate_bdev() */
#include <linux/completion.h>
struct loop_device *lo = data;
struct bio *bio;
- /*
- * loop can be used in an encrypted device,
- * hence, it mustn't be stopped at all
- * because it could be indirectly used during suspension
- */
- current->flags |= PF_NOFREEZE;
-
set_user_nice(current, -20);
while (!kthread_should_stop() || lo->lo_bio) {
long min_sleep_time, residue;
set_user_nice(current, -20);
+ set_freezable();
for (;;) {
DECLARE_WAITQUEUE(wait, current);
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/apm-emulation.h>
+#include <linux/freezer.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/list.h>
/*
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
- *
- * Note: we need to ensure that the PM subsystem does
- * not kick us out of the wait when it suspends the
- * threads.
*/
flags = current->flags;
- current->flags |= PF_NOFREEZE;
wait_event(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
/*
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
- *
- * Note: we need to ensure that the PM subsystem does
- * not kick us out of the wait when it suspends the
- * threads.
*/
flags = current->flags;
- current->flags |= PF_NOFREEZE;
wait_event_interruptible(apm_suspend_waitqueue,
as->suspend_state == SUSPEND_DONE);
kapmd_tsk = NULL;
return ret;
}
- kapmd_tsk->flags |= PF_NOFREEZE;
wake_up_process(kapmd_tsk);
#ifdef CONFIG_PROC_FS
int poll_mask;
struct hvc_struct *hp;
+ set_freezable();
__set_current_state(TASK_RUNNING);
do {
poll_mask = 0;
static int edac_kernel_thread(void *arg)
{
+ set_freezable();
while (!kthread_should_stop()) {
do_edac_check();
#include <linux/moduleparam.h>
#include <linux/bitops.h>
#include <linux/kdev_t.h>
+#include <linux/freezer.h>
#include <linux/suspend.h>
#include <linux/kthread.h>
#include <linux/preempt.h>
struct list_head tmp;
int may_schedule;
- current->flags |= PF_NOFREEZE;
-
while (!kthread_should_stop()) {
INIT_LIST_HEAD(&tmp);
unsigned int g, generation = 0;
int i, reset_cycles = 0;
+ set_freezable();
/* Setup our device-model entries */
nodemgr_create_host_dev_files(host);
static int gameport_thread(void *nothing)
{
+ set_freezable();
do {
gameport_handle_event();
wait_event_interruptible(gameport_wait,
static int serio_thread(void *nothing)
{
+ set_freezable();
do {
serio_handle_event();
wait_event_interruptible(serio_wait,
sched_setscheduler(tsk, SCHED_FIFO, ¶m);
+ set_freezable();
while (!kthread_should_stop()) {
unsigned int x, y, p;
long timeout;
{
struct thermostat* th = arg;
+ set_freezable();
while(!kthread_should_stop()) {
try_to_freeze();
msleep_interruptible(2000);
DBG("wf: thread started\n");
+ set_freezable();
while(!kthread_should_stop()) {
if (time_after_eq(jiffies, next)) {
wf_notify(WF_EVENT_TICK, NULL);
* many dirty RAID5 blocks.
*/
- current->flags |= PF_NOFREEZE;
allow_signal(SIGKILL);
while (!kthread_should_stop()) {
dvb_frontend_init(fe);
+ set_freezable();
while (1) {
up(&fepriv->sem); /* is locked when we enter the thread... */
restart:
u32 mode = 0;
dprintk("cx88: tvaudio thread started\n");
+ set_freezable();
for (;;) {
msleep_interruptible(1000);
if (kthread_should_stop())
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
+#include <linux/freezer.h>
#include <linux/videodev.h>
#include <linux/videodev2.h>
#include <media/v4l2-common.h>
v4l_dbg(1, msp_debug, client, "msp3400 daemon started\n");
+ set_freezable();
for (;;) {
v4l_dbg(2, msp_debug, client, "msp3400 thread: sleep\n");
msp_sleep(state, -1);
int val, i, std, count;
v4l_dbg(1, msp_debug, client, "msp3410 daemon started\n");
-
+ set_freezable();
for (;;) {
v4l_dbg(2, msp_debug, client, "msp3410 thread: sleep\n");
msp_sleep(state,-1);
int val, i;
v4l_dbg(1, msp_debug, client, "msp34xxg daemon started\n");
-
+ set_freezable();
for (;;) {
v4l_dbg(2, msp_debug, client, "msp34xxg thread: sleep\n");
msp_sleep(state, -1);
struct CHIPDESC *desc = chiplist + chip->type;
v4l_dbg(1, debug, &chip->c, "%s: thread started\n", chip->c.name);
-
+ set_freezable();
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop())
int err;
dprintk("dvb thread started\n");
+ set_freezable();
videobuf_read_start(&dvb->dvbq);
for (;;) {
dprintk(1,"thread started\n");
mod_timer(&dma_q->timeout, jiffies+BUFFER_TIMEOUT);
+ set_freezable();
for (;;) {
vivi_sleep(dma_q);
DECLARE_WAITQUEUE(wait, tsk);
int valid = 0;
+ set_freezable();
add_wait_queue(&ts->irq_wait, &wait);
while (!kthread_should_stop()) {
unsigned int x, y, p;
*/
#include <linux/module.h>
#include <linux/blkdev.h>
+#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/mmc/card.h>
struct mmc_queue *mq = d;
struct request_queue *q = mq->queue;
- /*
- * Set iothread to ensure that we aren't put to sleep by
- * the process freezing. We handle suspension ourselves.
- */
- current->flags |= PF_MEMALLOC|PF_NOFREEZE;
+ current->flags |= PF_MEMALLOC;
down(&mq->thread_sem);
do {
#include <linux/mtd/mtd.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
+#include <linux/freezer.h>
#include <linux/spinlock.h>
#include <linux/hdreg.h>
#include <linux/init.h>
struct request_queue *rq = tr->blkcore_priv->rq;
/* we might get involved when memory gets low, so use PF_MEMALLOC */
- current->flags |= PF_MEMALLOC | PF_NOFREEZE;
+ current->flags |= PF_MEMALLOC;
spin_lock_irq(rq->queue_lock);
while (!kthread_should_stop()) {
ubi_msg("background thread \"%s\" started, PID %d",
ubi->bgt_name, current->pid);
+ set_freezable();
for (;;) {
int err;
struct net_device *dev = data;
struct airo_info *ai = dev->priv;
int locked;
-
+
+ set_freezable();
while(1) {
/* make swsusp happy with our thread */
try_to_freeze();
init_waitqueue_entry(&wait, current);
+ set_freezable();
for (;;) {
lbs_deb_thread( "main-thread 111: intcounter=%d "
"currenttxskb=%p dnld_sent=%d\n",
add_wait_queue(&skt->thread_wait, &wait);
complete(&skt->thread_done);
+ set_freezable();
for (;;) {
unsigned long flags;
unsigned int events;
{
static struct pnp_docking_station_info now;
int docked = -1, d = 0;
+ set_freezable();
while (!unloading)
{
int status;
#include <linux/err.h>
#include <linux/blkdev.h>
+#include <linux/freezer.h>
#include <linux/scatterlist.h>
/* ---------- SCSI Host glue ---------- */
{
struct sas_ha_struct *sas_ha = _sas_ha;
- current->flags |= PF_NOFREEZE;
-
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/kernel.h>
+#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>
{
struct Scsi_Host *shost = data;
- current->flags |= PF_NOFREEZE;
-
/*
* We use TASK_INTERRUPTIBLE so that the thread is not
* counted against the load average as a running process.
struct uea_softc *sc = data;
int ret = -EAGAIN;
+ set_freezable();
uea_enters(INS_TO_USBDEV(sc));
while (!kthread_should_stop()) {
if (ret < 0 || sc->reset)
static int hub_thread(void *__unused)
{
+ set_freezable();
do {
hub_events();
wait_event_interruptible(khubd_wait,
allow_signal(SIGKILL);
allow_signal(SIGUSR1);
+ /* Allow the thread to be frozen */
+ set_freezable();
+
/* Arrange for userspace references to be interpreted as kernel
* pointers. That way we can pass a kernel pointer to a routine
* that expects a __user pointer and it will work okay. */
struct Scsi_Host *host = us_to_host(us);
int autopm_rc;
- current->flags |= PF_NOFREEZE;
-
for(;;) {
US_DEBUGP("*** thread sleeping.\n");
if(down_interruptible(&us->sema))
printk(KERN_DEBUG
"usb-storage: device found at %d\n", us->pusb_dev->devnum);
+ set_freezable();
/* Wait for the timeout to expire or for a disconnect */
if (delay_use > 0) {
printk(KERN_DEBUG "usb-storage: waiting for device "
static int ps3fbd(void *arg)
{
+ set_freezable();
while (!kthread_should_stop()) {
try_to_freeze();
set_current_state(TASK_INTERRUPTIBLE);
struct w1_master *dev, *n;
int have_to_wait = 0;
+ set_freezable();
while (!kthread_should_stop() || have_to_wait) {
have_to_wait = 0;
__u16 netfid;
int rc;
+ set_freezable();
do {
if (try_to_freeze())
continue;
GFP_KERNEL);
}
+ set_freezable();
while (!kthread_should_stop()) {
if (try_to_freeze())
continue;
set_user_nice(current, 10);
+ set_freezable();
for (;;) {
allow_signal(SIGHUP);
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
+#include <linux/freezer.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/stats.h>
complete(&lockd_start_done);
daemonize("lockd");
+ set_freezable();
/* Process request with signals blocked, but allow SIGKILL. */
allow_signal(SIGKILL);
#include <linux/sunrpc/svcsock.h>
#include <linux/nfs_fs.h>
#include <linux/mutex.h>
+#include <linux/freezer.h>
#include <net/inet_sock.h>
daemonize("nfsv4-svc");
/* Process request with signals blocked, but allow SIGKILL. */
allow_signal(SIGKILL);
+ set_freezable();
complete(&nfs_callback_info.started);
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
+#include <linux/freezer.h>
#include <linux/fs_struct.h>
#include <linux/sunrpc/types.h>
* dirty pages.
*/
current->flags |= PF_LESS_THROTTLE;
+ set_freezable();
/*
* The main request loop
bhv_vfs_sync_work_t *work, *n;
LIST_HEAD (tmp);
+ set_freezable();
timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
for (;;) {
timeleft = schedule_timeout_interruptible(timeleft);
/* Freezer declarations */
+#ifndef FREEZER_H_INCLUDED
+#define FREEZER_H_INCLUDED
+
#include <linux/sched.h>
#ifdef CONFIG_PM
return !!(p->flags & PF_FREEZER_SKIP);
}
+/*
+ * Tell the freezer that the current task should be frozen by it
+ */
+static inline void set_freezable(void)
+{
+ current->flags &= ~PF_NOFREEZE;
+}
+
#else
static inline int frozen(struct task_struct *p) { return 0; }
static inline int freezing(struct task_struct *p) { return 0; }
static inline void freezer_do_not_count(void) {}
static inline void freezer_count(void) {}
static inline int freezer_should_skip(struct task_struct *p) { return 0; }
+static inline void set_freezable(void) {}
#endif
+
+#endif /* FREEZER_H_INCLUDED */
sys_chroot(".");
pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD);
- if (pid > 0) {
- while (pid != sys_wait4(-1, NULL, 0, NULL)) {
- try_to_freeze();
+ if (pid > 0)
+ while (pid != sys_wait4(-1, NULL, 0, NULL))
yield();
- }
- }
/* move initrd to rootfs' /old */
sys_fchdir(old_fd);
{
struct sk_buff *skb;
+ set_freezable();
while (!kthread_should_stop()) {
skb = skb_dequeue(&audit_skb_queue);
wake_up(&audit_backlog_wait);
#include <linux/mempolicy.h>
#include <linux/taskstats_kern.h>
#include <linux/delayacct.h>
+#include <linux/freezer.h>
#include <linux/cpuset.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
* they would be locked into memory.
*/
exit_mm(current);
+ /*
+ * We don't want to have TIF_FREEZE set if the system-wide hibernation
+ * or suspend transition begins right now.
+ */
+ current->flags |= PF_NOFREEZE;
set_special_pids(1, 1);
proc_clear_tty(current);
{
unsigned long new_flags = p->flags;
- new_flags &= ~(PF_SUPERPRIV | PF_NOFREEZE);
+ new_flags &= ~PF_SUPERPRIV;
new_flags |= PF_FORKNOEXEC;
if (!(clone_flags & CLONE_PTRACE))
p->ptrace = 0;
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
+#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/random.h>
#include <linux/delay.h>
VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;
do {
schedule_timeout_uninterruptible(1);
VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;
do {
schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
set_user_nice(current, 19);
- current->flags |= PF_NOFREEZE;
do {
idx = cur_ops->readlock();
int ret;
current->flags |= PF_MUTEX_TESTER;
+ set_freezable();
allow_signal(SIGHUP);
for(;;) {
struct migration_req *req;
struct list_head *head;
- try_to_freeze();
-
spin_lock_irq(&rq->lock);
if (cpu_is_offline(cpu)) {
p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
if (IS_ERR(p))
return NOTIFY_BAD;
- p->flags |= PF_NOFREEZE;
kthread_bind(p, cpu);
/* Must be high prio: stop_machine expects to yield to it. */
rq = task_rq_lock(p, &flags);
#include <linux/notifier.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
+#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/rcupdate.h>
#include <linux/smp.h>
static int ksoftirqd(void * __bind_cpu)
{
- current->flags |= PF_NOFREEZE;
-
set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop()) {
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/delay.h>
+#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/notifier.h>
#include <linux/module.h>
struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
sched_setscheduler(current, SCHED_FIFO, ¶m);
- current->flags |= PF_NOFREEZE;
/* initialize timestamp */
touch_softlockup_watchdog();
struct cpu_workqueue_struct *cwq = __cwq;
DEFINE_WAIT(wait);
- if (!cwq->wq->freezeable)
- current->flags |= PF_NOFREEZE;
+ if (cwq->wq->freezeable)
+ set_freezable();
set_user_nice(current, -5);
static int __pdflush(struct pdflush_work *my_work)
{
current->flags |= PF_FLUSHER | PF_SWAPWRITE;
+ set_freezable();
my_work->fn = NULL;
my_work->who = current;
INIT_LIST_HEAD(&my_work->list);
* trying to free the first piece of memory in the first place).
*/
tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
+ set_freezable();
order = 0;
for ( ; ; ) {
#include <linux/signal.h>
#include <linux/init.h>
#include <linux/wait.h>
+#include <linux/freezer.h>
#include <linux/errno.h>
#include <linux/net.h>
#include <net/sock.h>
daemonize("kbnepd %s", dev->name);
set_user_nice(current, -15);
- current->flags |= PF_NOFREEZE;
init_waitqueue_entry(&wait, current);
add_wait_queue(sk->sk_sleep, &wait);
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fcntl.h>
+#include <linux/freezer.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/ioctl.h>
daemonize("kcmtpd_ctr_%d", session->num);
set_user_nice(current, -15);
- current->flags |= PF_NOFREEZE;
init_waitqueue_entry(&wait, current);
add_wait_queue(sk->sk_sleep, &wait);
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/poll.h>
+#include <linux/freezer.h>
#include <linux/fcntl.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
daemonize("khidpd_%04x%04x", vendor, product);
set_user_nice(current, -15);
- current->flags |= PF_NOFREEZE;
init_waitqueue_entry(&ctrl_wait, current);
init_waitqueue_entry(&intr_wait, current);
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/init.h>
+#include <linux/freezer.h>
#include <linux/wait.h>
#include <linux/device.h>
#include <linux/net.h>
daemonize("krfcommd");
set_user_nice(current, -10);
- current->flags |= PF_NOFREEZE;
BT_DBG("");
set_current_state(TASK_INTERRUPTIBLE);
+ set_freezable();
+
while (!kthread_should_stop()) {
pkt_dev = next_to_run(t);
projects / linux-2.6 / commitdiff