linux-toradex.git/kernel/trace/Kconfig, branch v5.10-rc3

Merge tag 'trace-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-06-09T17:06:18+00:00

Pull tracing updates from Steven Rostedt:
 "No new features this release. Mostly clean ups, restructuring and
  documentation.

   - Have ftrace_bug() show ftrace errors before the WARN, as the WARN
     will reboot the box before the error messages are printed if
     panic_on_warn is set.

   - Have traceoff_on_warn disable tracing sooner (before prints)

   - Write a message to the trace buffer that its being disabled when
     disable_trace_on_warning() is set.

   - Separate out synthetic events from histogram code to let it be used
     by other parts of the kernel.

   - More documentation on histogram design.

   - Other small fixes and clean ups"

* tag 'trace-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option
  tracing/doc: Fix ascii-art in histogram-design.rst
  tracing: Add a trace print when traceoff_on_warning is triggered
  ftrace,bug: Improve traceoff_on_warn
  selftests/ftrace: Distinguish between hist and synthetic event checks
  tracing: Move synthetic events to a separate file
  tracing: Fix events.rst section numbering
  tracing/doc: Fix typos in histogram-design.rst
  tracing: Add hist_debug trace event files for histogram debugging
  tracing: Add histogram-design document
  tracing: Check state.disabled in synth event trace functions
  tracing/probe: reverse arguments to list_add
  tools/bootconfig: Add a summary of test cases and return error
  ftrace: show debugging information when panic_on_warn set

tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option

2020-06-06T00:08:26+00:00

The PREEMPTIRQ_EVENTS option is unused after commit c3bc8fd637a9 ("tracing:
Centralize preemptirq tracepoints and unify their usage"). Remove it.

Note that this option is hazardous as it stands. It enables TRACE_IRQFLAGS
event on non-preempt configurations without the irqsoff tracer enabled.
TRACE_IRQFLAGS as it stands incurs significant overhead on each IRQ
entry/exit. This is because trace_hardirqs_[on|off] does all the per-cpu
manipulations and NMI checks even if tracing is completely disabled for
some insane reason.  For example, netperf running UDP_STREAM on localhost
incurs a 4-6% performance penalty without any tracing if IRQFLAGS is
set. It can be put behind a static brach but even the function entry/exit
costs a little bit.

Link: https://lkml.kernel.org/r/20200409104034.GJ3818@techsingularity.net

Signed-off-by: Mel Gorman 
Signed-off-by: Steven Rostedt (VMware)

tracing: Move synthetic events to a separate file

2020-06-01T12:23:22+00:00

With the addition of the in-kernel synthetic event API, synthetic
events are no longer specifically tied to the histogram triggers.

The synthetic event code is also making trace_event_hist.c very
bloated, so for those reasons, move it to a separate file,
trace_events_synth.c, along with a new trace_synth.h header file.

Because synthetic events are now independent from hist triggers, add a
new CONFIG_SYNTH_EVENTS config option, and have CONFIG_HIST_TRIGGERS
select it, and have CONFIG_SYNTH_EVENT_GEN_TEST depend on it.

Link: http://lkml.kernel.org/r/4d1fa1f85ed5982706ac44844ac92451dcb04715.1590693308.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)

tracing: Add hist_debug trace event files for histogram debugging

2020-06-01T12:22:30+00:00

Add a new "hist_debug" file for each trace event, which when read will
dump out a bunch of internal details about the hist triggers defined
on that event.

This is normally off but can be enabled by saying 'y' to the new
CONFIG_HIST_TRIGGERS_DEBUG config option.

This is in support of the new Documentation file describing histogram
internals, Documentation/trace/histogram-design.rst, which was
requested by developers trying to understand the internals when
extending or making use of the hist triggers for higher-level tools.

The histogram-design.rst documentation refers to the hist_debug files
and demonstrates their use with output in the test examples.

Link: http://lkml.kernel.org/r/77914c22b0ba493d9783c53bbfbc6087d6a7e1b1.1585941485.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi 
Signed-off-by: Steven Rostedt (VMware)

sh/ftrace: Move arch_ftrace_nmi_{enter,exit} into nmi exception

2020-05-19T13:51:18+00:00

SuperH is the last remaining user of arch_ftrace_nmi_{enter,exit}(),
remove it from the generic code and into the SuperH code.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Alexandre Chartre 
Acked-by: Steven Rostedt (VMware) 
Cc: Rich Felker 
Cc: Yoshinori Sato 
Link: https://lkml.kernel.org/r/20200505134101.248881738@linutronix.de

Merge tag 'noinstr-lds-2020-05-19' into core/rcu

2020-05-19T13:50:34+00:00

Get the noinstr section and annotation markers to base the RCU parts on.

Stop the ad-hoc games with -Wno-maybe-initialized

2020-05-09T20:57:10+00:00

We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds

ftrace: Use synchronize_rcu_tasks_rude() instead of ftrace_sync()

2020-04-27T18:03:53+00:00

This commit replaces the schedule_on_each_cpu(ftrace_sync) instances
with synchronize_rcu_tasks_rude().

Suggested-by: Steven Rostedt 
Cc: Ingo Molnar 
[ paulmck: Make Kconfig adjustments noted by kbuild test robot. ]
Signed-off-by: Paul E. McKenney

bootconfig: Fix CONFIG_BOOTTIME_TRACING dependency issue

2020-02-26T00:07:58+00:00

Since commit d8a953ddde5e ("bootconfig: Set CONFIG_BOOT_CONFIG=n by
default") also changed the CONFIG_BOOTTIME_TRACING to select
CONFIG_BOOT_CONFIG to show the boot-time tracing on the menu,
it introduced wrong dependencies with BLK_DEV_INITRD as below.

WARNING: unmet direct dependencies detected for BOOT_CONFIG
  Depends on [n]: BLK_DEV_INITRD [=n]
  Selected by [y]:
  - BOOTTIME_TRACING [=y] && TRACING_SUPPORT [=y] && FTRACE [=y] && TRACING [=y]

This makes the CONFIG_BOOT_CONFIG selects CONFIG_BLK_DEV_INITRD to
fix this error and make CONFIG_BOOTTIME_TRACING=n by default, so
that both boot-time tracing and boot configuration off but those
appear on the menu list.

Link: http://lkml.kernel.org/r/158264140162.23842.11237423518607465535.stgit@devnote2

Fixes: d8a953ddde5e ("bootconfig: Set CONFIG_BOOT_CONFIG=n by default")
Reported-by: Randy Dunlap 
Compiled-tested-by: Randy Dunlap 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

bootconfig: Set CONFIG_BOOT_CONFIG=n by default

2020-02-20T22:52:12+00:00

Set CONFIG_BOOT_CONFIG=n by default. This also warns
user if CONFIG_BOOT_CONFIG=n but "bootconfig" is given
in the kernel command line.

Link: http://lkml.kernel.org/r/158220111291.26565.9036889083940367969.stgit@devnote2

Suggested-by: Steven Rostedt 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)