linux-toradex.git/kernel/power/process.c, branch v2.6.25-rc2

power: Use task_is_*

2007-12-06T22:34:47+00:00

Signed-off-by: Matthew Wilcox

freezer: measure freezing time

2007-10-18T21:37:19+00:00

Measure the time of the freezing of tasks, even if it doesn't fail.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: be more verbose

2007-10-18T21:37:19+00:00

Increase the freezer's verbosity a bit, so that it's easier to read problem
reports related to it.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Nigel Cunningham 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: do not send signals to kernel threads

2007-10-18T21:37:19+00:00

The freezer should not send signals to kernel threads, since that may lead to
subtle problems.  In particular, commit
b74d0deb968e1f85942f17080eace015ce3c332c has changed recalc_sigpending_tsk()
so that it doesn't clear TIF_SIGPENDING.  For this reason, if the freezer
continues to send fake signals to kernel threads and the freezing of kernel
threads fails, some of them may be running with TIF_SIGPENDING set forever.

Accordingly, recalc_sigpending_tsk() shouldn't set the task's TIF_SIGPENDING
flag if TIF_FREEZE is set.

Signed-off-by: Rafael J. Wysocki 
Cc: Nigel Cunningham 
Cc: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: do not sync filesystems from freeze_processes

2007-10-18T21:37:18+00:00

The syncing of filesystems from within the freezer is generally not needed.
Also, if there's an ext3 filesystem loopback-mounted from a FUSE one, the
syncing results in writes to it and deadlocks.  Similarly, it will deadlock if
FUSE implements sync.

Change freeze_processes() so that it doesn't execute sys_sync() and make the
suspend and hibernation code path sync filesystems independently of the
freezer.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Cc: Nigel Cunningham 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Freezer: remove redundant check in try_to_freeze_tasks

2007-07-19T17:04:42+00:00

We don't need to check if todo is positive before calling time_after() in
try_to_freeze_tasks(), because if todo is zero at this point, the loop will be
broken anyway due to the while () condition being false.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Cc: Gautham R Shenoy 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Freezer: return int from freeze_processes

2007-07-19T17:04:42+00:00

Make try_to_freeze_tasks() and freeze_processes() return -EBUSY on failure
instead of the number of unfrozen tasks (none of the callers actually uses
this number).

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Cc: Gautham R Shenoy 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Freezer: use __set_current_state in refrigerator

2007-07-19T17:04:42+00:00

Use __set_current_state() as appropriate in refrigerator() instead of
accessing current->state directly.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Cc: Gautham R Shenoy 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Freezer: avoid freezing kernel threads prematurely

2007-07-19T17:04:42+00:00

Kernel threads should not have TIF_FREEZE set when user space processes are
being frozen, since otherwise some of them might be frozen prematurely.
To prevent this from happening we can (1) make exit_mm() unset TIF_FREEZE
unconditionally just after clearing tsk->mm and (2) make try_to_freeze_tasks()
check if p->mm is different from zero and PF_BORROWED_MM is unset in p->flags
when user space processes are to be frozen.

Namely, when user space processes are being frozen, we only should set
TIF_FREEZE for tasks that have p->mm different from NULL and don't have
PF_BORROWED_MM set in p->flags.  For this reason task_lock() must be used to
prevent try_to_freeze_tasks() from racing with use_mm()/unuse_mm(), in which
p->mm and p->flags.PF_BORROWED_MM are changed under task_lock(p).  Also, we
need to prevent the following scenario from happening:

* daemonize() is called by a task spawned from a user space code path
* freezer checks if the task has p->mm set and the result is positive
* task enters exit_mm() and clears its TIF_FREEZE
* freezer sets TIF_FREEZE for the task
* task calls try_to_freeze() and goes to the refrigerator, which is wrong at
  that point

This requires us to acquire task_lock(p) before p->flags.PF_BORROWED_MM and
p->mm are examined and release it after TIF_FREEZE is set for p (or it turns
out that TIF_FREEZE should not be set).

Signed-off-by: Rafael J. Wysocki 
Cc: Gautham R Shenoy 
Cc: Pavel Machek 
Cc: Nigel Cunningham 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: run show_state() when freezing times out

2007-07-19T17:04:42+00:00

To see which tasks are stuck where.

Cc: "Rafael J. Wysocki" 
Cc: Oleg Nesterov 
Cc: Alan Stern 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds