tracing/timers: Rename the hrtimer_init event to hrtimer_setup

The function hrtimer_init() doesn't exist anymore. It was replaced by
hrtimer_setup().

Thus, rename the hrtimer_init trace event to hr

tracing/timers: Rename the hrtimer_init event to hrtimer_setup

The function hrtimer_init() doesn't exist anymore. It was replaced by
hrtimer_setup().

Thus, rename the hrtimer_init trace event to hrtimer_setup to keep it
consistent.

Signed-off-by: Nam Cao <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/all/cba84c3d853c5258aa3a262363a6eac08e2c7afc.1738746927.git.namcao@linutronix.de

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hrtimers: Make callback function pointer private

Make the struct hrtimer::function field private, to prevent users from
changing this field in an unsafe way. hrtimer_update_function() should be
used

hrtimers: Make callback function pointer private

Make the struct hrtimer::function field private, to prevent users from
changing this field in an unsafe way. hrtimer_update_function() should be
used if the callback function needs to be changed.

Signed-off-by: Nam Cao <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/all/7d0e6e0c5c59a64a9bea940051aac05d750bc0c2.1738746927.git.namcao@linutronix.de

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tracing/timers: Add tracepoint for tracking timer base is_idle flag

When debugging timer code the timer tracepoints are very important. There
is no tracepoint when the is_idle flag of the timer base

tracing/timers: Add tracepoint for tracking timer base is_idle flag

When debugging timer code the timer tracepoints are very important. There
is no tracepoint when the is_idle flag of the timer base changes. Instead
of always adding manually trace_printk(), add tracepoints which can be
easily enabled whenever required.

Signed-off-by: Anna-Maria Behnsen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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tracing/timers: Enhance timer_start tracepoint

For starting a timer, the timer is enqueued into a bucket of the timer
wheel. The bucket expiry is the defacto expiry of the timer but it is not
equal

tracing/timers: Enhance timer_start tracepoint

For starting a timer, the timer is enqueued into a bucket of the timer
wheel. The bucket expiry is the defacto expiry of the timer but it is not
equal the timer expiry because of increasing granularity when bucket is in
a higher level of the wheel. To be able to figure out in a trace whether a
timer expired in time or not, the bucket expiry time is required as well.

Add bucket expiry time to the timer_start tracepoint and thereby simplify
the arguments.

Signed-off-by: Anna-Maria Behnsen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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tracing/timer: Add missing hrtimer modes to decode_hrtimer_mode().

The trace output for the HRTIMER_MODE_.*_HARD modes is seen as a number
since these modes are not decoded. The author was not aware

tracing/timer: Add missing hrtimer modes to decode_hrtimer_mode().

The trace output for the HRTIMER_MODE_.*_HARD modes is seen as a number
since these modes are not decoded. The author was not aware of the fancy
decoding function which makes the life easier.

Extend decode_hrtimer_mode() with the additional HRTIMER_MODE_.*_HARD
modes.

Fixes: ae6683d815895 ("hrtimer: Introduce HARD expiry mode")
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Mukesh Ojha <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check

This commit adds checks for the TICK_DEP_MASK_RCU_EXP bit, thus enabling
RCU expedited grace periods to actually force-enable scheduling-clock

rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check

This commit adds checks for the TICK_DEP_MASK_RCU_EXP bit, thus enabling
RCU expedited grace periods to actually force-enable scheduling-clock
interrupts on holdout CPUs.

Fixes: df1e849ae455 ("rcu: Enable tick for nohz_full CPUs slow to provide expedited QS")
Signed-off-by: Zqiang <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Anna-Maria Behnsen <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Joel Fernandes (Google) <[email protected]>

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tracing/timer: Add missing argument documentation of trace points

Documentation of trace points timer_start, timer_expire_entry and
hrtimer_start lack always the last argument. Add it to keep implem

tracing/timer: Add missing argument documentation of trace points

Documentation of trace points timer_start, timer_expire_entry and
hrtimer_start lack always the last argument. Add it to keep implementation
and documentation in sync.

Signed-off-by: Anna-Maria Behnsen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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tracing: Fix various typos in comments

Fix ~59 single-word typos in the tracing code comments, and fix
the grammar in a handful of places.

Link: https://lore.kernel.org/r/20210322224546.GA1981273@g

tracing: Fix various typos in comments

Fix ~59 single-word typos in the tracing code comments, and fix
the grammar in a handful of places.

Link: https://lore.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]

Reviewed-by: Randy Dunlap <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>

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y2038: itimer: change implementation to timespec64

There is no 64-bit version of getitimer/setitimer since that is not
actually needed. However, the implementation is built around the
deprecated 'st

y2038: itimer: change implementation to timespec64

There is no 64-bit version of getitimer/setitimer since that is not
actually needed. However, the implementation is built around the
deprecated 'struct timeval' type.

Change the code to use timespec64 internally to reduce the dependencies
on timeval and associated helper functions.

Minor adjustments in the code are needed to make the native and compat
version work the same way, and to keep the range check working after
the conversion.

Signed-off-by: Arnd Bergmann <[email protected]>

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nohz: Add TICK_DEP_BIT_RCU

If a nohz_full CPU is looping in the kernel, the scheduling-clock tick
might nevertheless remain disabled. In !PREEMPT kernels, this can
prevent RCU's attempts to enlist

nohz: Add TICK_DEP_BIT_RCU

If a nohz_full CPU is looping in the kernel, the scheduling-clock tick
might nevertheless remain disabled. In !PREEMPT kernels, this can
prevent RCU's attempts to enlist the aid of that CPU's executions of
cond_resched(), which can in turn result in an arbitrarily delayed grace
period and thus an OOM. RCU therefore needs a way to enable a holdout
nohz_full CPU's scheduler-clock interrupt.

This commit therefore provides a new TICK_DEP_BIT_RCU value which RCU can
pass to tick_dep_set_cpu() and friends to force on the scheduler-clock
interrupt for a specified CPU or task. In some cases, rcutorture needs
to turn on the scheduler-clock tick, so this commit also exports the
relevant symbols to GPL-licensed modules.

Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

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timer/trace: Improve timer tracing

Timers are added to the timer wheel off by one. This is required in
case a timer is queued directly before incrementing jiffies to prevent
early timer expiry.

Whe

timer/trace: Improve timer tracing

Timers are added to the timer wheel off by one. This is required in
case a timer is queued directly before incrementing jiffies to prevent
early timer expiry.

When reading a timer trace and relying only on the expiry time of the timer
in the timer_start trace point and on the now in the timer_expiry_entry
trace point, it seems that the timer fires late. With the current
timer_expiry_entry trace point information only now=jiffies is printed but
not the value of base->clk. This makes it impossible to draw a conclusion
to the index of base->clk and makes it impossible to examine timer problems
without additional trace points.

Therefore add the base->clk value to the timer_expire_entry trace
point, to be able to calculate the index the timer base is located at
during collecting expired timers.

Signed-off-by: Anna-Maria Gleixner <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Steven Rostedt <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

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timer/trace: Replace deprecated vsprintf pointer extension %pf by %ps

Since commit 04b8eb7a4ccd ("symbol lookup: introduce
dereference_symbol_descriptor()") %pf is deprecated, because %ps is smart
e

timer/trace: Replace deprecated vsprintf pointer extension %pf by %ps

Since commit 04b8eb7a4ccd ("symbol lookup: introduce
dereference_symbol_descriptor()") %pf is deprecated, because %ps is smart
enough to handle function pointer dereference on platforms where such a
dereference is required.

While at it add proper line breaks to stay in the 80 character limit.

Signed-off-by: Anna-Maria Gleixner <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Steven Rostedt <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

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hrtimer: Add clock bases and hrtimer mode for softirq context

Currently hrtimer callback functions are always executed in hard interrupt
context. Users of hrtimers, which need their timer function t

hrtimer: Add clock bases and hrtimer mode for softirq context

Currently hrtimer callback functions are always executed in hard interrupt
context. Users of hrtimers, which need their timer function to be executed
in soft interrupt context, make use of tasklets to get the proper context.

Add additional hrtimer clock bases for timers which must expire in softirq
context, so the detour via the tasklet can be avoided. This is also
required for RT, where the majority of hrtimer is moved into softirq
hrtimer context.

The selection of the expiry mode happens via a mode bit. Introduce
HRTIMER_MODE_SOFT and the matching combinations with the ABS/REL/PINNED
bits and update the decoding of hrtimer_mode in tracepoints.

Signed-off-by: Anna-Maria Gleixner <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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tracing/hrtimer: Print the hrtimer mode in the 'hrtimer_start' tracepoint

The 'hrtimer_start' tracepoint lacks the mode information. The mode is
important because consecutive starts can switch from

tracing/hrtimer: Print the hrtimer mode in the 'hrtimer_start' tracepoint

The 'hrtimer_start' tracepoint lacks the mode information. The mode is
important because consecutive starts can switch from ABS to REL or from
PINNED to non PINNED.

Append the mode field.

Signed-off-by: Anna-Maria Gleixner <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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tracing/hrtimer: Fix tracing bugs by taking all clock bases and modes into account

So far only CLOCK_MONOTONIC and CLOCK_REALTIME were taken into account as
well as HRTIMER_MODE_ABS/REL in the hrtim

tracing/hrtimer: Fix tracing bugs by taking all clock bases and modes into account

So far only CLOCK_MONOTONIC and CLOCK_REALTIME were taken into account as
well as HRTIMER_MODE_ABS/REL in the hrtimer_init tracepoint. The query for
detecting the ABS or REL timer modes is not valid anymore, it got broken
by the introduction of HRTIMER_MODE_PINNED.

HRTIMER_MODE_PINNED is not evaluated in the hrtimer_init() call, but for the
sake of completeness print all given modes.

Signed-off-by: Anna-Maria Gleixner <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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timers: Make flags output in the timer_start tracepoint useful

The timer flags in the timer_start trace event contain lots of useful
information, but the meaning is not clear in the trace output. Ma

timers: Make flags output in the timer_start tracepoint useful

The timer flags in the timer_start trace event contain lots of useful
information, but the meaning is not clear in the trace output. Making tools
rely on the bit positions is bad as they might change over time.

Decode the flags in the print out. Tools can retrieve the bits and their
meaning from the trace format file.

Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1702101639290.4036@nanos

Requested-by: Arjan van de Ven <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>

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timers/itimer: Convert internal cputime_t units to nsec

Use the new nsec based cputime accessors as part of the whole cputime
conversion from cputime_t to nsecs.

Also convert itimers to use nsec ba

timers/itimer: Convert internal cputime_t units to nsec

Use the new nsec based cputime accessors as part of the whole cputime
conversion from cputime_t to nsecs.

Also convert itimers to use nsec based internal counters. This simplifies
it and removes the whole game with error/inc_error which served to deal
with cputime_t random granularity.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Wanpeng Li <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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ktime: Get rid of the union

ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machin

ktime: Get rid of the union

ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.

Get rid of the union and just keep ktime_t as simple typedef of type s64.

The conversion was done with coccinelle and some manual mopping up.

Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>

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tracing: Fix tick_stop tracepoint symbols for user export

The symbols used in the tick_stop tracepoint were not being converted
properly into integers in the trace_stop format file. Instead we had t

tracing: Fix tick_stop tracepoint symbols for user export

The symbols used in the tick_stop tracepoint were not being converted
properly into integers in the trace_stop format file. Instead we had this:

print fmt: "success=%d dependency=%s", REC->success,
__print_symbolic(REC->dependency, { 0, "NONE" },
{ (1 << TICK_DEP_BIT_POSIX_TIMER), "POSIX_TIMER" },
{ (1 << TICK_DEP_BIT_PERF_EVENTS), "PERF_EVENTS" },
{ (1 << TICK_DEP_BIT_SCHED), "SCHED" },
{ (1 << TICK_DEP_BIT_CLOCK_UNSTABLE), "CLOCK_UNSTABLE" })

User space tools have no idea how to parse "TICK_DEP_BIT_SCHED" or the other
symbols used to do the bit shifting. The reason is that the conversion was
done with using the TICK_DEP_MASK_* symbols which are just macros that
convert to the BIT shift itself (with the exception of NONE, which was
converted properly, because it doesn't use bits, and is defined as zero).

The TICK_DEP_BIT_* needs to be denoted by TRACE_DEFINE_ENUM() in order to
have this properly converted for user space tools to parse this event.

Cc: [email protected]
Cc: Frederic Weisbecker <[email protected]>
Fixes: e6e6cc22e067 ("nohz: Use enum code for tick stop failure tracing message")
Reported-by: Luiz Capitulino <[email protected]>
Tested-by: Luiz Capitulino <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>

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nohz: Use enum code for tick stop failure tracing message

It makes nohz tracing more lightweight, standard and easier to parse.

Examples:

user_loop-2904 [007] d..1 517.701126: tick_stop:

nohz: Use enum code for tick stop failure tracing message

It makes nohz tracing more lightweight, standard and easier to parse.

Examples:

user_loop-2904 [007] d..1 517.701126: tick_stop: success=1 dependency=NONE
user_loop-2904 [007] dn.1 518.021181: tick_stop: success=0 dependency=SCHED
posix_timers-6142 [007] d..1 1739.027400: tick_stop: success=0 dependency=POSIX_TIMER
user_loop-5463 [007] dN.1 1185.931939: tick_stop: success=0 dependency=PERF_EVENTS

Suggested-by: Peter Zijlstra <[email protected]>
Reviewed-by: Chris Metcalf <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Luiz Capitulino <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Viresh Kumar <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>

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timer: Replace timer base by a cpu index

Instead of storing a pointer to the per cpu tvec_base we can simply
cache a CPU index in the timer_list and use that to get hold of the
correct per cpu tvec_

timer: Replace timer base by a cpu index

Instead of storing a pointer to the per cpu tvec_base we can simply
cache a CPU index in the timer_list and use that to get hold of the
correct per cpu tvec_base. This is only used in lock_timer_base() and
the slightly larger code is peanuts versus the spinlock operation and
the d-cache foot print of the timer wheel.

Aside of that this allows to get rid of following nuisances:

- boot_tvec_base

That statically allocated 4k bss data is just kept around so the
timer has a home when it gets statically initialized. It serves no
other purpose.

With the CPU index we assign the timer to CPU0 at static
initialization time and therefor can avoid the whole boot_tvec_base
dance. That also simplifies the init code, which just can use the
per cpu base.

Before:
text data bss dec hex filename
17491 9201 4160 30852 7884 ../build/kernel/time/timer.o
After:
text data bss dec hex filename
17440 9193 0 26633 6809 ../build/kernel/time/timer.o

- Overloading the base pointer with various flags

The CPU index has enough space to hold the flags (deferrable,
irqsafe) so we can get rid of the extra masking and bit fiddling
with the base pointer.

As a benefit we reduce the size of struct timer_list on 64 bit
machines. 4 - 8 bytes, a size reduction up to 15% per struct timer_list,
which is a real win as we have tons of them embedded in other structs.

This changes also the newly added deferrable printout of the timer
start trace point to capture and print all timer->flags, which allows
us to decode the target cpu of the timer as well.

We might have used bitfields for this, but that would change the
static initializers and the init function for no value to accomodate
big endian bitfields.

Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Paul McKenney <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Joonwoo Park <[email protected]>
Cc: Wenbo Wang <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Badhri Jagan Sridharan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

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tracing: timer: Add deferrable flag to timer_start

The timer_start event now shows whether the timer is
deferrable in case of a low-res timer. The debug_activate
function now includes a deferrable f

tracing: timer: Add deferrable flag to timer_start

The timer_start event now shows whether the timer is
deferrable in case of a low-res timer. The debug_activate
function now includes a deferrable flag while calling
the trace_timer_start event.

Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Signed-off-by: Badhri Jagan Sridharan <[email protected]>
[jstultz: Fixed minor whitespace and grammer tweaks
pointed out by Ingo]
Signed-off-by: John Stultz <[email protected]>

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nohz: Fix unavailable tick_stop tracepoint in dynticks idle

The trace_tick_stop() tracepoint is only available in full
dynticks. But it's also used by dynticks-idle so let's build
it for the latter

nohz: Fix unavailable tick_stop tracepoint in dynticks idle

The trace_tick_stop() tracepoint is only available in full
dynticks. But it's also used by dynticks-idle so let's build
it for the latter config as well.

This fixes:

kernel/time/tick-sched.c: In function tick_nohz_stop_sched_tick:
kernel/time/tick-sched.c:644: error: implicit declaration of function trace_tick_stop
make[2]: *** [kernel/time/tick-sched.o] Erreur 1

Reported-by: Ingo Molnar <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Geoff Levand <[email protected]>
Cc: Gilad Ben Yossef <[email protected]>
Cc: Hakan Akkan <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Li Zhong <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>

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nohz: Add basic tracing

It's not obvious to find out why the full dynticks subsystem
doesn't always stop the tick: whether this is due to kthreads,
posix timers, perf events, etc...

These new trace

nohz: Add basic tracing

It's not obvious to find out why the full dynticks subsystem
doesn't always stop the tick: whether this is due to kthreads,
posix timers, perf events, etc...

These new tracepoints are here to help the user diagnose
the failures and test this feature.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Geoff Levand <[email protected]>
Cc: Gilad Ben Yossef <[email protected]>
Cc: Hakan Akkan <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Li Zhong <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>

show more ...