linux.git/kernel/time, branch v2.6.21

[PATCH] fix jiffies clocksource inittime

2007-04-05T04:12:47+00:00

In debugging a problem w/ the -rt tree, I noticed that on systems that mark
the tsc as unstable before it is registered, the TSC would still be
selected and used for a short period of time.  Digging in it looks to be a
result of the mix of the clocksource list changes and my clocksource
initialization changes.

With the -rt tree, using a bad TSC, even for a short period of time can
results in a hang at boot.  I was not able to reproduce this hang w/
mainline, but I'm not completely certain that someone won't trip on it.

This patch resolves the issue by initializing the jiffies clocksource
earlier so a bad TSC won't get selected just because nothing else is yet
registered.

Signed-off-by: John Stultz 
Acked-by: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] ntp: avoid time_offset overflows

2007-03-27T16:05:15+00:00

I've been seeing some odd NTP behavior recently on a few boxes and
finally narrowed it down to time_offset overflowing when converted to
SHIFT_UPDATE units (which was a side effect from my HZfreeNTP patch).

This patch converts time_offset from a long to a s64 which resolves the
issue.

[tglx@linutronix.de: signedness fixes]
Signed-off-by: John Stultz 
Cc: Roman Zippel 
Cc: john stultz 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] clockevents: remove bad designed sysfs support for now

2007-03-26T21:07:23+00:00

The current sysfs support of clockevents does not obey the "only one
value per file" rule.

The real fix is not 2.6.21 material. Therefor remove the sysfs support
for now.

Signed-off-by: Thomas Gleixner 
Acked-by: Ingo Molnar 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Linus Torvalds

[PATCH] clocksource: Fix thinko in watchdog selection

2007-03-25T21:57:34+00:00

The watchdog implementation excludes low res / non continuous
clocksources from being selected as a watchdog reference
unintentionally.

Allow using jiffies/PIT as a watchdog reference as long as no better
clocksource is available. This is necessary to detect TSC breakage on
systems, which have no pmtimer/hpet.

The main goal of the initial patch (preventing to switch to highres/nohz
when no reliable fallback clocksource is available) is still guaranteed
by the checks in clocksource_watchdog().

Signed-off-by: Thomas Gleixner 
Signed-off-by: Linus Torvalds

[PATCH] time: fix formatting in /proc/timer_list

2007-03-23T18:01:21+00:00

Fix the print formatting of three unsigned long fields in /proc/timer_list,
which are currently being formatted as signed long.

Signed-off-by: James Morris 
Acked-by: Ingo Molnar 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] clockevents: Fix suspend/resume to disk hangs

2007-03-17T02:35:25+00:00

I finally found a dual core box, which survives suspend/resume without
crashing in the middle of nowhere. Sigh, I never figured out from the
code and the bug reports what's going on.

The observed hangs are caused by a stale state transition of the clock
event devices, which keeps the RCU synchronization away from completion,
when the non boot CPU is brought back up.

The suspend/resume in oneshot mode needs the similar care as the
periodic mode during suspend to RAM. My assumption that the state
transitions during the different shutdown/bringups of s2disk would go
through the periodic boot phase and then switch over to highres resp.
nohz mode were simply wrong.

Add the appropriate suspend / resume handling for the non periodic
modes.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Linus Torvalds

[PATCH] Save/restore periodic tick information over suspend/resume

2007-03-06T17:30:24+00:00

The programming of periodic tick devices needs to be saved/restored
across suspend/resume - otherwise we might end up with a system coming
up that relies on getting a PIT (or HPET) interrupt, while those devices
default to 'no interrupts' after powerup. (To confuse things it worked
to a certain degree on some systems because the lapic gets initialized
as a side-effect of SMP bootup.)

This suspend / resume thing was dropped unintentionally during the
last-minute -mm code reshuffling.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Signed-off-by: Linus Torvalds

[PATCH] clocksource init adjustments (fix bug #7426)

2007-03-05T15:57:53+00:00

This patch resolves the issue found here:
http://bugme.osdl.org/show_bug.cgi?id=7426

The basic summary is:
Currently we register most of i386/x86_64 clocksources at module_init
time. Then we enable clocksource selection at late_initcall time. This
causes some problems for drivers that use gettimeofday for init
calibration routines (specifically the es1968 driver in this case),
where durring module_init, the only clocksource available is the low-res
jiffies clocksource. This may cause slight calibration errors, due to
the small sampling time used.

It should be noted that drivers that require fine grained time may not
function on architectures that do not have better then jiffies
resolution timekeeping (there are a few). However, this does not
discount the reasonable need for such fine-grained timekeeping at init
time.

Thus the solution here is to register clocksources earlier (ideally when
the hardware is being initialized), and then we enable clocksource
selection at fs_initcall (before device_initcall).

This patch should probably get some testing time in -mm, since
clocksource selection is one of the most important issues for correct
timekeeping, and I've only been able to test this on a few of my own
boxes.

Signed-off-by: John Stultz 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "David S. Miller" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[TICK] tick-common: Fix one-shot handling in tick_handle_periodic().

2007-02-26T19:14:15+00:00

When clockevents_program_event() is given an expire time in the
past, it does not update dev->next_event, so this looping code
would loop forever once the first in-the-past expiration time
was used.

Keep advancing "next" locally to fix this bug.

Acked-by: Thomas Gleixner 
Signed-off-by: David S. Miller

[TIME] tick-sched: Add missing asm/irq_regs.h include.

2007-02-26T19:13:49+00:00

Acked-by: Thomas Gleixner 
Signed-off-by: David S. Miller