linux.git/kernel/time/timekeeping.c, branch v3.6-rc2

time: Fix adjustment cleanup bug in timekeeping_adjust()

2012-08-05T10:37:14+00:00

Tetsuo Handa reported that sporadically the system clock starts
counting up too quickly which is enough to confuse the hangcheck
timer to print a bogus stall warning.

Commit 2a8c0883 "time: Move xtime_nsec adjustment underflow handling
timekeeping_adjust" overlooked this exit path:

        } else
                return;

which should really be a proper exit sequence, fixing the bug as a
side effect.

Also make the flow more readable by properly balancing curly
braces.

Reported-by: Tetsuo Handa  wrote:
Tested-by: Tetsuo Handa  wrote:
Signed-off-by: Ingo Molnar 
Cc: john.stultz@linaro.org
Cc: a.p.zijlstra@chello.nl
Cc: richardcochran@gmail.com
Cc: prarit@redhat.com
Link: http://lkml.kernel.org/r/20120804192114.GA28347@gmail.com
Signed-off-by: Ingo Molnar

time: Remove all direct references to timekeeper

2012-07-31T15:09:14+00:00

Ingo noted that the numerous timekeeper.value references made
the timekeeping code ugly and caused many long lines that
had to be broken up. He recommended replacing timekeeper.value
references with tk->value.

This patch provides a local tk value for all top level time
functions and sets it to &timekeeper. Then all timekeeper
access is done via a tk pointer.

Signed-off-by: John Stultz 
Cc: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1343414893-45779-6-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar

time: Clean up offs_real/wall_to_mono and offs_boot/total_sleep_time updates

2012-07-31T15:09:14+00:00

For performance reasons, we maintain ktime_t based duplicates of
wall_to_monotonic (offs_real) and total_sleep_time (offs_boot).

Since large problems could occur (such as the resume regression
on 3.5-rc7, or the leapsecond hrtimer issue) if these value
pairs were to be inconsistently updated, this patch this cleans
up how we modify these value pairs to ensure we are always
consistent.

As a side-effect this is also more efficient as we only
caulculate the duplicate values when they are changed,
rather then every update_wall_time call.

This also provides WARN_ONs to detect if future changes break
the invariants.

Signed-off-by: John Stultz 
Cc: Peter Zijlstra 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1343414893-45779-5-git-send-email-john.stultz@linaro.org
[ Cleaned up minor style issues. ]
Signed-off-by: Ingo Molnar

time: Clean up stray newlines

2012-07-31T15:09:13+00:00

Ingo noted inconsistent newline usage between functions.
This patch cleans those up.

Signed-off-by: John Stultz 
Cc: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1343414893-45779-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar

Merge branch 'linus' into timers/urgent

2012-07-31T15:05:27+00:00

Merge in Linus's branch which already has timers/core merged.

Signed-off-by: Ingo Molnar

time: Fix casting issue in tk_set_xtime and tk_xtime_add

2012-07-24T14:48:45+00:00

commit 1e75fa8b (time: Condense timekeeper.xtime into xtime_sec)
introduced helper functions which apply a timespec to the core
internal timekeeper data. The internal storage type is u64. The
timespec tv_nsec value must be shifted before set or added to the
internal value. tv_nsec is a long, which is 32bit on a 32bit system,
so without casting tv_nsec to u64 we lose the bits which are shifted
over the 32bit boundary.

Add the proper typecasts.

Reported-by: Konrad Rzeszutek Wilk 
Tested-by: Konrad Rzeszutek Wilk 
Signed-off-by: John Stultz 
Acked-by: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1343074957-16541-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner

Merge branch 'linus' into timers/core

2012-07-18T09:25:55+00:00

Resolve semantic conflict in kernel/time/timekeeping.c.

Signed-off-by: Ingo Molnar

timekeeping: Add missing update call in timekeeping_resume()

2012-07-16T17:02:17+00:00

The leap second rework unearthed another issue of inconsistent data.

On timekeeping_resume() the timekeeper data is updated, but nothing
calls timekeeping_update(), so now the update code in the timer
interrupt sees stale values.

This has been the case before those changes, but then the timer
interrupt was using stale data as well so this went unnoticed for quite
some time.

Add the missing update call, so all the data is consistent everywhere.

Reported-by: Andreas Schwab 
Reported-and-tested-by: "Rafael J. Wysocki" 
Reported-and-tested-by: Martin Steigerwald 
Cc: LKML 
Cc: Linux PM list 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Peter Zijlstra ,
Cc: Prarit Bhargava 
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Linus Torvalds

time: Rework timekeeping functions to take timekeeper ptr as argument

2012-07-15T08:39:07+00:00

As part of cleaning up the timekeeping code, this patch converts
a number of internal functions to takei a timekeeper ptr as an
argument, so that the internal functions don't access the global
timekeeper structure directly. This allows for further optimizations
to reduce lock hold time later.

This patch has been updated to include more consistent usage of the
timekeeper value, by making sure it is always passed as a argument
to non top-level functions.

Signed-off-by: John Stultz 
Reviewed-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1342156917-25092-9-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner

time: Move xtime_nsec adjustment underflow handling timekeeping_adjust

2012-07-15T08:39:07+00:00

When we make adjustments speeding up the clock, its possible
for xtime_nsec to underflow. We already handle this properly,
but we do so from update_wall_time() instead of the more logical
timekeeping_adjust(), where the possible underflow actually
occurs.

Thus, move the correction logic to the timekeeping_adjust, which
is the function that causes the issue. Making update_wall_time()
more readable.

Signed-off-by: John Stultz 
Reviewed-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1342156917-25092-8-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner