<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/include/linux/trace_events.h, branch v5.13.16</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v5.13.16</id>
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<updated>2021-04-01T18:18:32Z</updated>
<entry>
<title>tracing: Remove duplicate struct declaration in trace_events.h</title>
<updated>2021-04-01T18:18:32Z</updated>
<author>
<name>Wan Jiabing</name>
<email>wanjiabing@vivo.com</email>
</author>
<published>2021-03-30T03:40:55Z</published>
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<id>urn:sha1:1decdb335c366fc0a1bae0db55c138c613cc9a1f</id>
<content type='text'>
struct trace_array is declared twice. One has been declared
at forward declaration. Remove the duplicate.

Link: https://lkml.kernel.org/r/20210330034056.2266969-1-wanjiabing@vivo.com

Signed-off-by: Wan Jiabing &lt;wanjiabing@vivo.com&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Fix various typos in comments</title>
<updated>2021-03-23T18:08:18Z</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2021-03-23T17:49:35Z</published>
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<id>urn:sha1:f2cc020d7876de7583feb52ec939a32419cf9468</id>
<content type='text'>
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@gmail.com
Link: https://lkml.kernel.org/r/20210323174935.GA4176821@gmail.com

Reviewed-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Pass buffer of event to trigger operations</title>
<updated>2021-03-18T16:58:26Z</updated>
<author>
<name>Steven Rostedt (VMware)</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2021-03-16T16:41:03Z</published>
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<id>urn:sha1:b47e330231acbf4506b049643145cc64268a1940</id>
<content type='text'>
The ring_buffer_event_time_stamp() is going to be updated to extract the
time stamp for the event without needing it to be set to have absolute
values for all events. But to do so, it needs the buffer that the event is
on as the buffer saves information for the event before it is committed to
the buffer.

If the trace buffer is disabled, a temporary buffer is used, and there's
no access to this buffer from the current histogram triggers, even though
it is passed to the trace event code.

Pass the buffer that the event is on all the way down to the histogram
triggers.

Link: https://lkml.kernel.org/r/20210316164113.542448131@goodmis.org

Reviewed-by: Tom Zanussi &lt;zanussi@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Fix comment about the trace_event_call flags</title>
<updated>2021-03-04T14:51:50Z</updated>
<author>
<name>Steven Rostedt (VMware)</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2021-02-26T19:09:15Z</published>
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<id>urn:sha1:f9f344479d8b40b3b001c913fb992d85d19261d0</id>
<content type='text'>
In the declaration of the struct trace_event_call, the flags has the bits
defined in the comment above it. But these bits are also defined by the
TRACE_EVENT_FL_* enums just above the declaration of the struct. As the
comment about the flags in the struct has become stale and incorrect, just
replace it with a reference to the TRACE_EVENT_FL_* enum above.

Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Show real address for trace event arguments</title>
<updated>2021-02-11T21:31:57Z</updated>
<author>
<name>Masami Hiramatsu</name>
<email>mhiramat@kernel.org</email>
</author>
<published>2020-10-15T14:55:07Z</published>
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<id>urn:sha1:efbbdaa22bb78761bff8dfdde027ad04bedd47ce</id>
<content type='text'>
To help debugging kernel, show real address for trace event arguments
in tracefs/trace{,pipe} instead of hashed pointer value.

Since ftrace human-readable format uses vsprintf(), all %p are
translated to hash values instead of pointer address.

However, when debugging the kernel, raw address value gives a
hint when comparing with the memory mapping in the kernel.
(Those are sometimes used with crash log, which is not hashed too)
So converting %p with %px when calling trace_seq_printf().

Moreover, this is not improving the security because the tracefs
can be used only by root user and the raw address values are readable
from tracefs/percpu/cpu*/trace_pipe_raw file.

Link: https://lkml.kernel.org/r/160277370703.29307.5134475491761971203.stgit@devnote2

Signed-off-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Remove NULL check from current in tracing_generic_entry_update().</title>
<updated>2021-02-02T22:02:06Z</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2021-01-25T19:45:11Z</published>
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<id>urn:sha1:5817708493bec547914d23dcdd064919ac409f33</id>
<content type='text'>
I can't imagine when or why `current' would return a NULL pointer. This
check was added in commit
      72829bc3d63cd ("ftrace: move enums to ftrace.h and make helper function global")

but it doesn't give me hint why it was needed.

Assume `current' never returns a NULL pointer and remove the check.

Link: https://lkml.kernel.org/r/20210125194511.3924915-5-bigeasy@linutronix.de

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Inline tracing_gen_ctx_flags()</title>
<updated>2021-02-02T22:02:06Z</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2021-01-25T19:45:09Z</published>
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<id>urn:sha1:0c02006e6f5b0a3e73499bbf5943d9174c5ed640</id>
<content type='text'>
Inline tracing_gen_ctx_flags(). This allows to have one ifdef
CONFIG_TRACE_IRQFLAGS_SUPPORT.

This requires to move `trace_flag_type' so tracing_gen_ctx_flags() can
use it.

Link: https://lkml.kernel.org/r/20210125194511.3924915-3-bigeasy@linutronix.de

Suggested-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Link: https://lkml.kernel.org/r/20210125140323.6b1ff20c@gandalf.local.home
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>tracing: Merge irqflags + preempt counter.</title>
<updated>2021-02-02T22:02:06Z</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2021-01-25T19:45:08Z</published>
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<id>urn:sha1:36590c50b2d0729952511129916beeea30d31d81</id>
<content type='text'>
The state of the interrupts (irqflags) and the preemption counter are
both passed down to tracing_generic_entry_update(). Only one bit of
irqflags is actually required: The on/off state. The complete 32bit
of the preemption counter isn't needed. Just whether of the upper bits
(softirq, hardirq and NMI) are set and the preemption depth is needed.

The irqflags and the preemption counter could be evaluated early and the
information stored in an integer `trace_ctx'.
tracing_generic_entry_update() would use the upper bits as the
TRACE_FLAG_* and the lower 8bit as the disabled-preemption depth
(considering that one must be substracted from the counter in one
special cases).

The actual preemption value is not used except for the tracing record.
The `irqflags' variable is mostly used only for the tracing record. An
exception here is for instance wakeup_tracer_call() or
probe_wakeup_sched_switch() which explicilty disable interrupts and use
that `irqflags' to save (and restore) the IRQ state and to record the
state.

Struct trace_event_buffer has also the `pc' and flags' members which can
be replaced with `trace_ctx' since their actual value is not used
outside of trace recording.

This will reduce tracing_generic_entry_update() to simply assign values
to struct trace_entry. The evaluation of the TRACE_FLAG_* bits is moved
to _tracing_gen_ctx_flags() which replaces preempt_count() and
local_save_flags() invocations.

As an example, ftrace_syscall_enter() may invoke:
- trace_buffer_lock_reserve() -&gt; … -&gt; tracing_generic_entry_update()
- event_trigger_unlock_commit()
  -&gt; ftrace_trace_stack() -&gt; … -&gt; tracing_generic_entry_update()
  -&gt; ftrace_trace_userstack() -&gt; … -&gt; tracing_generic_entry_update()

In this case the TRACE_FLAG_* bits were evaluated three times. By using
the `trace_ctx' they are evaluated once and assigned three times.

A build with all tracers enabled on x86-64 with and without the patch:

    text     data      bss      dec      hex    filename
21970669 17084168  7639260 46694097  2c87ed1 vmlinux.old
21970293 17084168  7639260 46693721  2c87d59 vmlinux.new

text shrank by 379 bytes, data remained constant.

Link: https://lkml.kernel.org/r/20210125194511.3924915-2-bigeasy@linutronix.de

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>treewide: Convert macro and uses of __section(foo) to __section("foo")</title>
<updated>2020-10-25T21:51:49Z</updated>
<author>
<name>Joe Perches</name>
<email>joe@perches.com</email>
</author>
<published>2020-10-22T02:36:07Z</published>
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<id>urn:sha1:33def8498fdde180023444b08e12b72a9efed41d</id>
<content type='text'>
Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Reviewed-by: Nick Desaulniers &lt;ndesaulniers@gooogle.com&gt;
Reviewed-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>tracing: Save off entry when peeking at next entry</title>
<updated>2020-03-19T21:48:36Z</updated>
<author>
<name>Steven Rostedt (VMware)</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2020-03-17T21:32:23Z</published>
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<id>urn:sha1:ff895103a84abc85a5f43ecabc7f67cf36e1348f</id>
<content type='text'>
In order to have the iterator read the buffer even when it's still updating,
it requires that the ring buffer iterator saves each event in a separate
location outside the ring buffer such that its use is immutable.

There's one use case that saves off the event returned from the ring buffer
interator and calls it again to look at the next event, before going back to
use the first event. As the ring buffer iterator will only have a single
copy, this use case will no longer be supported.

Instead, have the one use case create its own buffer to store the first
event when looking at the next event. This way, when looking at the first
event again, it wont be corrupted by the second read.

Link: http://lkml.kernel.org/r/20200317213415.722539921@goodmis.org

Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
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