linux-stable.git/kernel/time/ntp.c, branch linux-2.6.29.y

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

Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2

2008-10-22T07:48:06+00:00

Conflicts:

	kernel/time/tick-sched.c

Signed-off-by: Thomas Gleixner

Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus

2008-10-20T11:14:06+00:00

Merge commit 'linus/master' into merge-linus

2008-10-17T16:20:26+00:00

Conflicts:

	arch/x86/kvm/i8254.c

ntp: improve adjtimex frequency rounding

2008-09-24T15:33:13+00:00

Change PPM_SCALE_INV_SHIFT so that it doesn't throw away any input bits
(19 is the amount of the factor 2 in PPM_SCALE), the output frequency
can then be calculated back to its input value, as the inverse divide
produce a slightly larger value, which is then correctly rounded by the
final shift.

Reported-by: Martin Ziegler 
Signed-off-by: Roman Zippel 
Cc: John Stultz 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner

ntp: let update_persistent_clock() sleep

2008-09-24T15:33:12+00:00

This is a change that makes the 11-minute RTC update be run in the process
context.  This is so that update_persistent_clock() can sleep, which may
be required for certain types of RTC hardware -- most notably I2C devices.

Signed-off-by: Maciej W. Rozycki 
Cc: Roman Zippel 
Cc: Rik van Riel 
Cc: David Brownell 
Acked-by: Alessandro Zummo 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner

ntp: fix calculation of the next jiffie to trigger RTC sync

2008-09-06T13:31:48+00:00

We have a bug in the calculation of the next jiffie to trigger the RTC
synchronisation.  The aim here is to run sync_cmos_clock() as close as
possible to the middle of a second.  Which means we want this function to
be called less than or equal to half a jiffie away from when now.tv_nsec
equals 5e8 (500000000).

If this is not the case for a given call to the function, for this purpose
instead of updating the RTC we calculate the offset in nanoseconds to the
next point in time where now.tv_nsec will be equal 5e8.  The calculated
offset is then converted to jiffies as these are the unit used by the
timer.

Hovewer timespec_to_jiffies() used here uses a ceil()-type rounding mode,
where the resulting value is rounded up.  As a result the range of
now.tv_nsec when the timer will trigger is from 5e8 to 5e8 + TICK_NSEC
rather than the desired 5e8 - TICK_NSEC / 2 to 5e8 + TICK_NSEC / 2.

As a result if for example sync_cmos_clock() happens to be called at the
time when now.tv_nsec is between 5e8 + TICK_NSEC / 2 and 5e8 to 5e8 +
TICK_NSEC, it will simply be rescheduled HZ jiffies later, falling in the
same range of now.tv_nsec again.  Similarly for cases offsetted by an
integer multiple of TICK_NSEC.

This change addresses the problem by subtracting TICK_NSEC / 2 from the
nanosecond offset to the next point in time where now.tv_nsec will be
equal 5e8, effectively shifting the following rounding in
timespec_to_jiffies() so that it produces a rounded-to-nearest result.

Signed-off-by: Maciej W. Rozycki 
Signed-off-by: Andrew Morton 
Signed-off-by: Ingo Molnar

hrtimer: convert kernel/* to the new hrtimer apis

2008-09-06T04:35:13+00:00

In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts kernel/* to these accessors.

Signed-off-by: Arjan van de Ven

ntp: fix ADJ_OFFSET_SS_READ bug and do_adjtimex() cleanup

2008-08-22T04:40:18+00:00

Thanks to the review by Michael Kerrisk a bug in the recent
ADJ_OFFSET_SS_READ option was discovered, where the ntp time_offset was
inadvertently set by it.  This fixes this by making the adjtime code
more separate from the ntp_adjtime code (both of which really want to
be separate syscalls).

Signed-off-by: Roman Zippel 
Signed-off-by: Andrew Morton 
Acked-by: John Stultz 
Signed-off-by: Ingo Molnar

ntp: handle leap second via timer

2008-05-01T15:03:59+00:00

Remove the leap second handling from second_overflow(), which doesn't have to
check for it every second anymore.  With CONFIG_NO_HZ this also makes sure the
leap second is handled close to the full second.  Additionally this makes it
possible to abort a leap second properly by resetting the STA_INS/STA_DEL
status bits.

Signed-off-by: Roman Zippel 
Cc: john stultz 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds