linux-toradex.git/kernel/kthread.c, branch v3.4.73

kthread_worker: reimplement flush_kthread_work() to allow freeing the work item being executed

2012-10-02T17:30:40+00:00

commit 46f3d976213452350f9d10b0c2780c2681f7075b upstream.

kthread_worker provides minimalistic workqueue-like interface for
users which need a dedicated worker thread (e.g. for realtime
priority).  It has basic queue, flush_work, flush_worker operations
which mostly match the workqueue counterparts; however, due to the way
flush_work() is implemented, it has a noticeable difference of not
allowing work items to be freed while being executed.

While the current users of kthread_worker are okay with the current
behavior, the restriction does impede some valid use cases.  Also,
removing this difference isn't difficult and actually makes the code
easier to understand.

This patch reimplements flush_kthread_work() such that it uses a
flush_work item instead of queue/done sequence numbers.

Signed-off-by: Tejun Heo 
Cc: Colin Cross 
Signed-off-by: Greg Kroah-Hartman

kthread_worker: reorganize to prepare for flush_kthread_work() reimplementation

2012-10-02T17:30:38+00:00

commit 9a2e03d8ed518a61154f18d83d6466628e519f94 upstream.

Make the following two non-functional changes.

* Separate out insert_kthread_work() from queue_kthread_work().

* Relocate struct kthread_flush_work and kthread_flush_work_fn()
  definitions above flush_kthread_work().

v2: Added lockdep_assert_held() in insert_kthread_work() as suggested
    by Andy Walls.

Signed-off-by: Tejun Heo 
Acked-by: Andy Walls 
Cc: Colin Cross 
Signed-off-by: Greg Kroah-Hartman

freezer: kill unused set_freezable_with_signal()

2011-11-23T17:28:17+00:00

There's no in-kernel user of set_freezable_with_signal() left.  Mixing
TIF_SIGPENDING with kernel threads can lead to nasty corner cases as
kernel threads never travel signal delivery path on their own.

e.g. the current implementation is buggy in the cancelation path of
__thaw_task().  It calls recalc_sigpending_and_wake() in an attempt to
clear TIF_SIGPENDING but the function never clears it regardless of
sigpending state.  This means that signallable freezable kthreads may
continue executing with !freezing() && stuck TIF_SIGPENDING, which can
be troublesome.

This patch removes set_freezable_with_signal() along with
PF_FREEZER_NOSIG and recalc_sigpending*() calls in freezer.  User
tasks get TIF_SIGPENDING, kernel tasks get woken up and the spurious
sigpending is dealt with in the usual signal delivery path.

Signed-off-by: Tejun Heo 
Acked-by: Oleg Nesterov

freezer: implement and use kthread_freezable_should_stop()

2011-11-21T20:32:23+00:00

Writeback and thinkpad_acpi have been using thaw_process() to prevent
deadlock between the freezer and kthread_stop(); unfortunately, this
is inherently racy - nothing prevents freezing from happening between
thaw_process() and kthread_stop().

This patch implements kthread_freezable_should_stop() which enters
refrigerator if necessary but is guaranteed to return if
kthread_stop() is invoked.  Both thaw_process() users are converted to
use the new function.

Note that this deadlock condition exists for many of freezable
kthreads.  They need to be converted to use the new should_stop or
freezable workqueue.

Tested with synthetic test case.

Signed-off-by: Tejun Heo 
Acked-by: Henrique de Moraes Holschuh 
Cc: Jens Axboe 
Cc: Oleg Nesterov

kernel: Map most files to use export.h instead of module.h

2011-10-31T13:20:12+00:00

The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include 
  +#include 

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker

cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed

2011-05-28T15:02:57+00:00

The rule is, we have to update tsk->rt.nr_cpus_allowed if we change
tsk->cpus_allowed. Otherwise RT scheduler may confuse.

Signed-off-by: KOSAKI Motohiro 
Cc: Oleg Nesterov 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/4DD4B3FA.5060901@jp.fujitsu.com
Signed-off-by: Ingo Molnar

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

kthread: NUMA aware kthread_create_on_node()

2011-03-23T00:44:01+00:00

All kthreads being created from a single helper task, they all use memory
from a single node for their kernel stack and task struct.

This patch suite creates kthread_create_on_node(), adding a 'cpu' parameter
to parameters already used by kthread_create().

This parameter serves in allocating memory for the new kthread on its
memory node if possible.

Signed-off-by: Eric Dumazet 
Acked-by: David S. Miller 
Reviewed-by: Andi Kleen 
Acked-by: Rusty Russell 
Cc: Tejun Heo 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: David Howells 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Constify function scope static struct sched_param usage

2011-01-07T14:55:45+00:00

Function-scope statics are discouraged because they are
easily overlooked and can cause subtle bugs/races due to
their global (non-SMP safe) nature.

Linus noticed that we did this for sched_param - at minimum
make the const.

Suggested-by: Linus Torvalds 
Signed-off-by: Peter Zijlstra 
LKML-Reference: Message-ID: 
Signed-off-by: Ingo Molnar

Merge commit 'v2.6.37' into sched/core

2011-01-05T13:14:46+00:00

Merge reason: Merge the final .37 tree.

Signed-off-by: Ingo Molnar