User events:
- Use long instead of int for storing the enable set/clear bit, as it was
found that big endian machines could end up using the wrong bits.
- Split allocating mm and attaching it. This keeps the allocation separate
from the registration and avoids various races.
- Remove RCU locking around pin_user_pages_remote() as that can schedule. The
RCU protection is no longer needed with the above split of mm allocation and
attaching.
- Rename the "link" fields of the various structs to something more
meaningful.
- Add comments around user_event_mm struct usage and locking requirements.
Timerlat tracer:
- Fix missed wakeup of timerlat thread caused by the timerlat interrupt
triggering when tracing is off. The timer interrupt handler needs to always
wake up the timerlat thread regardless if tracing is enabled or not,
otherwise, it will never wake up.
Histograms:
- Fix regression of breaking the "stacktrace" modifier for variables. That
modifier cannot be used for values, but can be used for variables that are
passed from one histogram to the next. This was broken when adding the
restriction to values as the variable logic used the same code.
- Rename the special field "stacktrace" to "common_stacktrace". Special fields
(that are not actually part of the event, but can act just like event
fields, like 'comm' and 'timestamp') should be prefixed with 'common_' for
consistency. To keep backward compatibility, 'stacktrace' can still be used
(as with the special field 'cpu'), but can be overridden if the event has a
field called 'stacktrace'.
- Update the synthetic event selftests to use the new name (synthetic events
are created by histograms)
Tracing bootup selftests:
- Reorganize the code to keep artifacts of the selftests not compiled in when
selftests are not configured.
- Add various cond_resched() around the selftest code, as the softlock
watchdog was triggering much more often. It appears that the kernel runs
slower now with full debugging enabled.
- While debugging ftrace with ftrace (using an instance ring buffer instead of
the top level one), I found that the selftests were disabling prints to the
debug instance. This should not happen, as the selftests only disable
printing to the main buffer as the selftests examine the main buffer to see
if it has what it expects, and prints can make the tests fail. Make the
selftests only disable printing to the toplevel buffer, and leave the
instance buffers alone.
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Merge tag 'trace-v6.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
"User events:
- Use long instead of int for storing the enable set/clear bit, as it
was found that big endian machines could end up using the wrong
bits.
- Split allocating mm and attaching it. This keeps the allocation
separate from the registration and avoids various races.
- Remove RCU locking around pin_user_pages_remote() as that can
schedule. The RCU protection is no longer needed with the above
split of mm allocation and attaching.
- Rename the "link" fields of the various structs to something more
meaningful.
- Add comments around user_event_mm struct usage and locking
requirements.
Timerlat tracer:
- Fix missed wakeup of timerlat thread caused by the timerlat
interrupt triggering when tracing is off. The timer interrupt
handler needs to always wake up the timerlat thread regardless if
tracing is enabled or not, otherwise, it will never wake up.
Histograms:
- Fix regression of breaking the "stacktrace" modifier for variables.
That modifier cannot be used for values, but can be used for
variables that are passed from one histogram to the next. This was
broken when adding the restriction to values as the variable logic
used the same code.
- Rename the special field "stacktrace" to "common_stacktrace".
Special fields (that are not actually part of the event, but can
act just like event fields, like 'comm' and 'timestamp') should be
prefixed with 'common_' for consistency. To keep backward
compatibility, 'stacktrace' can still be used (as with the special
field 'cpu'), but can be overridden if the event has a field called
'stacktrace'.
- Update the synthetic event selftests to use the new name (synthetic
events are created by histograms)
Tracing bootup selftests:
- Reorganize the code to keep artifacts of the selftests not compiled
in when selftests are not configured.
- Add various cond_resched() around the selftest code, as the
softlock watchdog was triggering much more often. It appears that
the kernel runs slower now with full debugging enabled.
- While debugging ftrace with ftrace (using an instance ring buffer
instead of the top level one), I found that the selftests were
disabling prints to the debug instance.
This should not happen, as the selftests only disable printing to
the main buffer as the selftests examine the main buffer to see if
it has what it expects, and prints can make the tests fail.
Make the selftests only disable printing to the toplevel buffer,
and leave the instance buffers alone"
* tag 'trace-v6.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Have function_graph selftest call cond_resched()
tracing: Only make selftest conditionals affect the global_trace
tracing: Make tracing_selftest_running/delete nops when not used
tracing: Have tracer selftests call cond_resched() before running
tracing: Move setting of tracing_selftest_running out of register_tracer()
tracing/selftests: Update synthetic event selftest to use common_stacktrace
tracing: Rename stacktrace field to common_stacktrace
tracing/histograms: Allow variables to have some modifiers
tracing/user_events: Document user_event_mm one-shot list usage
tracing/user_events: Rename link fields for clarity
tracing/user_events: Remove RCU lock while pinning pages
tracing/user_events: Split up mm alloc and attach
tracing/timerlat: Always wakeup the timerlat thread
tracing/user_events: Use long vs int for atomic bit ops
8b817fded4