linux-toradex.git/include/linux/hrtimer.h, branch tegra-10.9.9

hrtimer: Fix /proc/timer_list regression

2009-12-18T22:03:28+00:00

commit 8629ea2eaba8ca0de2e38ce1b4a825e16255976e upstream.

commit 507e1231 (timer stats: Optimize by adding quick check to avoid
function calls) introduced a regression in /proc/timer_list.

/proc/timer_list shows now
 #0: , tick_sched_timer, S:01, <(null)>, /-1
instead of
 #0: , tick_sched_timer, S:01, hrtimer_start, swapper/0

Revert the hrtimer quick check for now. The optimization needs more
thought, but this is neither 2.6.32-rc7 nor stable material.

[ tglx: - Removed unrelated changes from the original patch
  	- Prevent unneccesary call to timer_stats_update_stats
	- massaged the changelog ]

Signed-off-by: Feng Tang 
LKML-Reference: 
Cc: Heiko Carstens 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'linus' into timers/core

2009-08-14T13:59:30+00:00

Reason: Martin's timekeeping cleanup series depends on both
timers/core and mainline changes.

Signed-off-by: Thomas Gleixner

hrtimer: Remove cb_entry from struct hrtimer

2009-07-22T15:12:32+00:00

It's unused, remove it.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Thomas Gleixner 
LKML-Reference:

timer stats: fix quick check optimization

2009-07-10T17:33:00+00:00

git commit 507e1231 "timer stats: Optimize by adding quick check to
avoid function calls" added one wrong check so that one unnecessary
function call isn't elimated.

time_stats_account_hrtimer() checks if timer->start_pid isn't
initialized in order to find out if timer_stats_update_stats() should
be called.  However start_pid is initialized with -1 instead of 0, so
that the function call always happens.

Check timer->start_site like in timer_stats_account_timer() to fix
this.

Signed-off-by: Heiko Carstens 
Signed-off-by: Thomas Gleixner

timer stats: Optimize by adding quick check to avoid function calls

2009-06-24T09:15:09+00:00

When the kernel is configured with CONFIG_TIMER_STATS but timer
stats are runtime disabled we still get calls to
__timer_stats_timer_set_start_info which initializes some
fields in the corresponding struct timer_list.

So add some quick checks in the the timer stats setup functions
to avoid function calls to __timer_stats_timer_set_start_info
when timer stats are disabled.

In an artificial workload that does nothing but playing ping
pong with a single tcp packet via loopback this decreases cpu
consumption by 1 - 1.5%.

This is part of a modified function trace output on SLES11:

 perl-2497  [00] 28630647177732388 [+  125]: sk_reset_timer <-tcp_v4_rcv
 perl-2497  [00] 28630647177732513 [+  125]: mod_timer <-sk_reset_timer
 perl-2497  [00] 28630647177732638 [+  125]: __timer_stats_timer_set_start_info <-mod_timer
 perl-2497  [00] 28630647177732763 [+  125]: __mod_timer <-mod_timer
 perl-2497  [00] 28630647177732888 [+  125]: __timer_stats_timer_set_start_info <-__mod_timer
 perl-2497  [00] 28630647177733013 [+   93]: lock_timer_base <-__mod_timer

Signed-off-by: Heiko Carstens 
Cc: Andrew Morton 
Cc: Martin Schwidefsky 
Cc: Mustafa Mesanovic 
Cc: Arjan van de Ven 
LKML-Reference: <20090623153811.GA4641@osiris.boeblingen.de.ibm.com>
Signed-off-by: Ingo Molnar

timers: Framework for identifying pinned timers

2009-05-13T14:52:42+00:00

* Arun R Bharadwaj  [2009-04-16 12:11:36]:

This patch creates a new framework for identifying cpu-pinned timers
and hrtimers.

This framework is needed because pinned timers are expected to fire on
the same CPU on which they are queued. So it is essential to identify
these and not migrate them, in case there are any.

For regular timers, the currently existing add_timer_on() can be used
queue pinned timers and subsequently mod_timer_pinned() can be used
to modify the 'expires' field.

For hrtimers, new modes HRTIMER_ABS_PINNED and HRTIMER_REL_PINNED are
added to queue cpu-pinned hrtimer.

[ tglx: use .._PINNED mode argument instead of creating tons of new
functions ]

Signed-off-by: Arun R Bharadwaj 
Signed-off-by: Thomas Gleixner

hrtimer: fix rq->lock inversion (again)

2009-03-31T12:52:52+00:00

It appears I inadvertly introduced rq->lock recursion to the
hrtimer_start() path when I delegated running already expired
timers to softirq context.

This patch fixes it by introducing a __hrtimer_start_range_ns()
method that will not use raise_softirq_irqoff() but
__raise_softirq_irqoff() which avoids the wakeup.

It then also changes schedule() to check for pending softirqs and
do the wakeup then, I'm not quite sure I like this last bit, nor
am I convinced its really needed.

Signed-off-by: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: paulus@samba.org
LKML-Reference: <20090313112301.096138802@chello.nl>
Signed-off-by: Ingo Molnar

hrtimer: removing all ur callback modes

2008-11-25T14:45:46+00:00

Impact: cleanup, move all hrtimer processing into hardirq context

This is an attempt at removing some of the hrtimer complexity by
reducing the number of callback modes to 1.

This means that all hrtimer callback functions will be ran from HARD-irq
context.

I went through all the 30 odd hrtimer callback functions in the kernel
and saw only one that I'm not quite sure of, which is the one in
net/can/bcm.c - hence I'm CC-ing the folks responsible for that code.

Furthermore, the hrtimer core now calls callbacks directly with IRQs
disabled in case you try to enqueue an expired timer. If this timer is a
periodic timer (which should use hrtimer_forward() to advance its time)
then it might be possible to end up in an inf. recursive loop due to the
fact that hrtimer_forward() doesn't round up to the next timer
granularity, and therefore keeps on calling the callback - obviously
this needs a fix.

Aside from that, this seems to compile and actually boot on my dual core
test box - although I'm sure there are some bugs in, me not hitting any
makes me certain :-)

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

hrtimer: clean up unused callback modes

2008-11-12T08:54:40+00:00

Impact: cleanup

git grep HRTIMER_CB_IRQSAFE revealed half the callback modes are actually
unused.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

Fix accidental implicit cast in HR-timer conversion

2008-11-06T23:44:19+00:00

Fix the hrtimer_add_expires_ns() function.  It should take a 'u64 ns' argument,
but rather takes an 'unsigned long ns' argument - which might only be 32-bits.

On FRV, this results in the kernel locking up because hrtimer_forward() passes
the result of a 64-bit multiplication to this function, for which the compiler
discards the top 32-bits - something that didn't happen when ktime_add_ns() was
called directly.

Signed-off-by: David Howells 
Acked-by: Arjan van de Ven 
Signed-off-by: Linus Torvalds