linux-toradex.git/kernel/sched/cputime.c, branch v3.8.4

Merge tag 'sched-cputime-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core

2012-12-08T14:44:43+00:00

Pull more cputime cleanups from Frederic Weisbecker:

 * Get rid of underscores polluting the vtime namespace

 * Consolidate context switch and tick handling

 * Improve debuggability by detecting irq unsafe callers

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Ingo Molnar

cputime: Comment cputime's adjusting code

2012-11-28T16:08:20+00:00

The reason for the scaling and monotonicity correction performed
by cputime_adjust() may not be immediately clear to the reviewer.

Add some comments to explain what happens there.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker

cputime: Consolidate cputime adjustment code

2012-11-28T16:08:10+00:00

task_cputime_adjusted() and thread_group_cputime_adjusted()
essentially share the same code. They just don't use the same
source:

* The first function uses the cputime in the task struct and the
previous adjusted snapshot that ensures monotonicity.

* The second adds the cputime of all tasks in the group and the
previous adjusted snapshot of the whole group from the signal
structure.

Just consolidate the common code that does the adjustment. These
functions just need to fetch the values from the appropriate
source.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker

cputime: Rename thread_group_times to thread_group_cputime_adjusted

2012-11-28T16:07:57+00:00

We have thread_group_cputime() and thread_group_times(). The naming
doesn't provide enough information about the difference between
these two APIs.

To lower the confusion, rename thread_group_times() to
thread_group_cputime_adjusted(). This name better suggests that
it's a version of thread_group_cputime() that does some stabilization
on the raw cputime values. ie here: scale on top of CFS runtime
stats and bound lower value for monotonicity.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker

cputime: Move thread_group_cputime() to sched code

2012-11-28T16:07:38+00:00

thread_group_cputime() is a general cputime API that is not only
used by posix cpu timer. Let's move this helper to sched code.

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker

vtime: No need to disable irqs on vtime_account()

2012-11-19T15:41:41+00:00

vtime_account() is only called from irq entry. irqs
are always disabled at this point so we can safely
remove the irq disabling guards on that function.

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens

vtime: Consolidate a bit the ctx switch code

2012-11-19T15:41:32+00:00

On ia64 and powerpc, vtime context switch only consists
in flushing system and user pending time, plus a few
arch housekeeping.

Consolidate that into a generic implementation. s390 is
a special case because pending user and system time accounting
there is hard to dissociate. So it's keeping its own implementation.

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens

vtime: Remove the underscore prefix invasion

2012-11-19T15:40:16+00:00

Prepending irq-unsafe vtime APIs with underscores was actually
a bad idea as the result is a big mess in the API namespace that
is even waiting to be further extended. Also these helpers
are always called from irq safe callers except kvm. Just
provide a vtime_account_system_irqsafe() for this specific
case so that we can remove the underscore prefix on other
vtime functions.

Signed-off-by: Frederic Weisbecker 
Reviewed-by: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens

cputime: Separate irqtime accounting from generic vtime

2012-10-29T20:31:32+00:00

vtime_account() doesn't have the same role in
CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_IRQ_TIME_ACCOUNTING.

In the first case it handles time accounting in any context. In
the second case it only handles irq time accounting.

So when vtime_account() is called from outside vtime_account_irq_*()
this call is pointless to CONFIG_IRQ_TIME_ACCOUNTING.

To fix the confusion, change vtime_account() to irqtime_account_irq()
in CONFIG_IRQ_TIME_ACCOUNTING. This way we ensure future account_vtime()
calls won't waste useless cycles in the irqtime APIs.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker

vtime: Make vtime_account_system() irqsafe

2012-10-29T20:31:31+00:00

vtime_account_system() currently has only one caller with
vtime_account() which is irq safe.

Now we are going to call it from other places like kvm where
irqs are not always disabled by the time we account the cputime.

So let's make it irqsafe. The arch implementation part is now
prefixed with "__".

vtime_account_idle() arch implementation is prefixed accordingly
to stay consistent.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Steven Rostedt 
Cc: Paul Gortmaker 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens