<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/tools/perf/builtin-timechart.c, branch v6.7</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>perf addr_location: Add init/exit/copy functions</title>
<updated>2023-06-12T18:57:53+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-06-08T23:28:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0dd5041c9a0eaf8c5c3fd46df4ee60f877799f44'/>
<id>0dd5041c9a0eaf8c5c3fd46df4ee60f877799f44</id>
<content type='text'>
struct addr_location holds references to multiple reference counted
objects. Add init/exit functions to make maintenance of those more
consistent with the rest of the code and to try to avoid
leaks. Modification of thread reference counts isn't included in this
change.

Committer notes:

I needed to initialize result to sample-&gt;ip to make sure is set to
something, fixing a compile time error, mostly keeping the previous
logic as build_alloc_func_list() already does debugging/error prints
about what went wrong if it takes the 'goto out'.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ali Saidi &lt;alisaidi@amazon.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Brian Robbins &lt;brianrob@linux.microsoft.com&gt;
Cc: Changbin Du &lt;changbin.du@huawei.com&gt;
Cc: Dmitrii Dolgov &lt;9erthalion6@gmail.com&gt;
Cc: Fangrui Song &lt;maskray@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Ivan Babrou &lt;ivan@cloudflare.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jing Zhang &lt;renyu.zj@linux.alibaba.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Naveen N. Rao &lt;naveen.n.rao@linux.vnet.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Steinar H. Gunderson &lt;sesse@google.com&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Wenyu Liu &lt;liuwenyu7@huawei.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Cc: Ye Xingchen &lt;ye.xingchen@zte.com.cn&gt;
Cc: Yuan Can &lt;yuancan@huawei.com&gt;
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230608232823.4027869-7-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
struct addr_location holds references to multiple reference counted
objects. Add init/exit functions to make maintenance of those more
consistent with the rest of the code and to try to avoid
leaks. Modification of thread reference counts isn't included in this
change.

Committer notes:

I needed to initialize result to sample-&gt;ip to make sure is set to
something, fixing a compile time error, mostly keeping the previous
logic as build_alloc_func_list() already does debugging/error prints
about what went wrong if it takes the 'goto out'.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ali Saidi &lt;alisaidi@amazon.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Brian Robbins &lt;brianrob@linux.microsoft.com&gt;
Cc: Changbin Du &lt;changbin.du@huawei.com&gt;
Cc: Dmitrii Dolgov &lt;9erthalion6@gmail.com&gt;
Cc: Fangrui Song &lt;maskray@google.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Ivan Babrou &lt;ivan@cloudflare.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jing Zhang &lt;renyu.zj@linux.alibaba.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Naveen N. Rao &lt;naveen.n.rao@linux.vnet.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Steinar H. Gunderson &lt;sesse@google.com&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Wenyu Liu &lt;liuwenyu7@huawei.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Cc: Ye Xingchen &lt;ye.xingchen@zte.com.cn&gt;
Cc: Yuan Can &lt;yuancan@huawei.com&gt;
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230608232823.4027869-7-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf timechart: Make large arrays dynamic</title>
<updated>2023-05-28T13:23:42+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-05-26T18:33:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ddc27bb8a9a5c0236ae65c3451d9c7024040d11d'/>
<id>ddc27bb8a9a5c0236ae65c3451d9c7024040d11d</id>
<content type='text'>
Allocate start time and state arrays when command starts rather than
using 114,688 bytes in .bss.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20230526183401.2326121-11-irogers@google.com
Cc: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Ross Zwisler &lt;zwisler@chromium.org&gt;
Cc: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Allocate start time and state arrays when command starts rather than
using 114,688 bytes in .bss.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20230526183401.2326121-11-irogers@google.com
Cc: K Prateek Nayak &lt;kprateek.nayak@amd.com&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Ross Zwisler &lt;zwisler@chromium.org&gt;
Cc: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf util: Move input_name to util</title>
<updated>2023-04-10T22:21:31+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2023-04-10T16:25:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f12ad2727bbed890cbc2890470fb00c95b089b28'/>
<id>f12ad2727bbed890cbc2890470fb00c95b089b28</id>
<content type='text'>
'input_name' is the name of the input perf.data file, it is used by data
convert and ui code. Move it to util to make it more consistent with
other global state.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Chengdong Li &lt;chengdongli@tencent.com&gt;
Cc: Denis Nikitin &lt;denik@chromium.org&gt;
Cc: Florian Fischer &lt;florian.fischer@muhq.space&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Martin Liška &lt;mliska@suse.cz&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Raul Silvera &lt;rsilvera@google.com&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Xing Zhengjun &lt;zhengjun.xing@linux.intel.com&gt;
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230410162511.3055900-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
'input_name' is the name of the input perf.data file, it is used by data
convert and ui code. Move it to util to make it more consistent with
other global state.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Chengdong Li &lt;chengdongli@tencent.com&gt;
Cc: Denis Nikitin &lt;denik@chromium.org&gt;
Cc: Florian Fischer &lt;florian.fischer@muhq.space&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: James Clark &lt;james.clark@arm.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.g.garry@oracle.com&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Leo Yan &lt;leo.yan@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Martin Liška &lt;mliska@suse.cz&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Raul Silvera &lt;rsilvera@google.com&gt;
Cc: Ravi Bangoria &lt;ravi.bangoria@amd.com&gt;
Cc: Rob Herring &lt;robh@kernel.org&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Suzuki Poulouse &lt;suzuki.poulose@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: Xing Zhengjun &lt;zhengjun.xing@linux.intel.com&gt;
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230410162511.3055900-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf build: Use libtraceevent from the system</title>
<updated>2022-12-14T14:16:12+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2022-12-05T22:59:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=378ef0f5d9d7f4652d7a40e0711e8b845ada1cbd'/>
<id>378ef0f5d9d7f4652d7a40e0711e8b845ada1cbd</id>
<content type='text'>
Remove the LIBTRACEEVENT_DYNAMIC and LIBTRACEFS_DYNAMIC make command
line variables.

If libtraceevent isn't installed or NO_LIBTRACEEVENT=1 is passed to the
build, don't compile in libtraceevent and libtracefs support.

This also disables CONFIG_TRACE that controls "perf trace".

CONFIG_LIBTRACEEVENT is used to control enablement in Build/Makefiles,
HAVE_LIBTRACEEVENT is used in C code.

Without HAVE_LIBTRACEEVENT tracepoints are disabled and as such the
commands kmem, kwork, lock, sched and timechart are removed.  The
majority of commands continue to work including "perf test".

Committer notes:

Fixed up a tools/perf/util/Build reject and added:

  #include &lt;traceevent/event-parse.h&gt;

to tools/perf/util/scripting-engines/trace-event-perl.c.

Committer testing:

  $ rpm -qi libtraceevent-devel
  Name        : libtraceevent-devel
  Version     : 1.5.3
  Release     : 2.fc36
  Architecture: x86_64
  Install Date: Mon 25 Jul 2022 03:20:19 PM -03
  Group       : Unspecified
  Size        : 27728
  License     : LGPLv2+ and GPLv2+
  Signature   : RSA/SHA256, Fri 15 Apr 2022 02:11:58 PM -03, Key ID 999f7cbf38ab71f4
  Source RPM  : libtraceevent-1.5.3-2.fc36.src.rpm
  Build Date  : Fri 15 Apr 2022 10:57:01 AM -03
  Build Host  : buildvm-x86-05.iad2.fedoraproject.org
  Packager    : Fedora Project
  Vendor      : Fedora Project
  URL         : https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
  Bug URL     : https://bugz.fedoraproject.org/libtraceevent
  Summary     : Development headers of libtraceevent
  Description :
  Development headers of libtraceevent-libs
  $

Default build:

  $ ldd ~/bin/perf | grep tracee
  	libtraceevent.so.1 =&gt; /lib64/libtraceevent.so.1 (0x00007f1dcaf8f000)
  $

  # perf trace -e sched:* --max-events 10
       0.000 migration/0/17 sched:sched_migrate_task(comm: "", pid: 1603763 (perf), prio: 120, dest_cpu: 1)
       0.005 migration/0/17 sched:sched_wake_idle_without_ipi(cpu: 1)
       0.011 migration/0/17 sched:sched_switch(prev_comm: "", prev_pid: 17 (migration/0), prev_state: 1, next_comm: "", next_prio: 120)
       1.173 :0/0 sched:sched_wakeup(comm: "", pid: 3138 (gnome-terminal-), prio: 120)
       1.180 :0/0 sched:sched_switch(prev_comm: "", prev_prio: 120, next_comm: "", next_pid: 3138 (gnome-terminal-), next_prio: 120)
       0.156 migration/1/21 sched:sched_migrate_task(comm: "", pid: 1603763 (perf), prio: 120, orig_cpu: 1, dest_cpu: 2)
       0.160 migration/1/21 sched:sched_wake_idle_without_ipi(cpu: 2)
       0.166 migration/1/21 sched:sched_switch(prev_comm: "", prev_pid: 21 (migration/1), prev_state: 1, next_comm: "", next_prio: 120)
       1.183 :0/0 sched:sched_wakeup(comm: "", pid: 1602985 (kworker/u16:0-f), prio: 120, target_cpu: 1)
       1.186 :0/0 sched:sched_switch(prev_comm: "", prev_prio: 120, next_comm: "", next_pid: 1602985 (kworker/u16:0-f), next_prio: 120)
  #

Had to tweak tools/perf/util/setup.py to make sure the python binding
shared object links with libtraceevent if -DHAVE_LIBTRACEEVENT is
present in CFLAGS.

Building with NO_LIBTRACEEVENT=1 uncovered some more build failures:

- Make building of data-convert-bt.c to CONFIG_LIBTRACEEVENT=y

- perf-$(CONFIG_LIBTRACEEVENT) += scripts/

- bpf_kwork.o needs also to be dependent on CONFIG_LIBTRACEEVENT=y

- The python binding needed some fixups and util/trace-event.c can't be
  built and linked with the python binding shared object, so remove it
  in tools/perf/util/setup.py and exclude it from the list of
  dependencies in the python/perf.so Makefile.perf target.

Building without libtraceevent-devel installed uncovered more build
failures:

- The python binding tools/perf/util/python.c was assuming that
  traceevent/parse-events.h was always available, which was the case
  when we defaulted to using the in-kernel tools/lib/traceevent/ files,
  now we need to enclose it under ifdef HAVE_LIBTRACEEVENT, just like
  the other parts of it that deal with tracepoints.

- We have to ifdef the rules in the Build files with
  CONFIG_LIBTRACEEVENT=y to build builtin-trace.c and
  tools/perf/trace/beauty/ as we only ifdef setting CONFIG_TRACE=y when
  setting NO_LIBTRACEEVENT=1 in the make command line, not when we don't
  detect libtraceevent-devel installed in the system. Simplification here
  to avoid these two ways of disabling builtin-trace.c and not having
  CONFIG_TRACE=y when libtraceevent-devel isn't installed is the clean
  way.

From Athira:

&lt;quote&gt;
tools/perf/arch/powerpc/util/Build
-perf-y += kvm-stat.o
+perf-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
&lt;/quote&gt;

Then, ditto for arm64 and s390, detected by container cross build tests.

- s/390 uses test__checkevent_tracepoint() that is now only available if
  HAVE_LIBTRACEEVENT is defined, enclose the callsite with ifder HAVE_LIBTRACEEVENT.

Also from Athira:

&lt;quote&gt;
With this change, I could successfully compile in these environment:
- Without libtraceevent-devel installed
- With libtraceevent-devel installed
- With “make NO_LIBTRACEEVENT=1”
&lt;/quote&gt;

Then, finally rename CONFIG_TRACEEVENT to CONFIG_LIBTRACEEVENT for
consistency with other libraries detected in tools/perf/.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20221205225940.3079667-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove the LIBTRACEEVENT_DYNAMIC and LIBTRACEFS_DYNAMIC make command
line variables.

If libtraceevent isn't installed or NO_LIBTRACEEVENT=1 is passed to the
build, don't compile in libtraceevent and libtracefs support.

This also disables CONFIG_TRACE that controls "perf trace".

CONFIG_LIBTRACEEVENT is used to control enablement in Build/Makefiles,
HAVE_LIBTRACEEVENT is used in C code.

Without HAVE_LIBTRACEEVENT tracepoints are disabled and as such the
commands kmem, kwork, lock, sched and timechart are removed.  The
majority of commands continue to work including "perf test".

Committer notes:

Fixed up a tools/perf/util/Build reject and added:

  #include &lt;traceevent/event-parse.h&gt;

to tools/perf/util/scripting-engines/trace-event-perl.c.

Committer testing:

  $ rpm -qi libtraceevent-devel
  Name        : libtraceevent-devel
  Version     : 1.5.3
  Release     : 2.fc36
  Architecture: x86_64
  Install Date: Mon 25 Jul 2022 03:20:19 PM -03
  Group       : Unspecified
  Size        : 27728
  License     : LGPLv2+ and GPLv2+
  Signature   : RSA/SHA256, Fri 15 Apr 2022 02:11:58 PM -03, Key ID 999f7cbf38ab71f4
  Source RPM  : libtraceevent-1.5.3-2.fc36.src.rpm
  Build Date  : Fri 15 Apr 2022 10:57:01 AM -03
  Build Host  : buildvm-x86-05.iad2.fedoraproject.org
  Packager    : Fedora Project
  Vendor      : Fedora Project
  URL         : https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
  Bug URL     : https://bugz.fedoraproject.org/libtraceevent
  Summary     : Development headers of libtraceevent
  Description :
  Development headers of libtraceevent-libs
  $

Default build:

  $ ldd ~/bin/perf | grep tracee
  	libtraceevent.so.1 =&gt; /lib64/libtraceevent.so.1 (0x00007f1dcaf8f000)
  $

  # perf trace -e sched:* --max-events 10
       0.000 migration/0/17 sched:sched_migrate_task(comm: "", pid: 1603763 (perf), prio: 120, dest_cpu: 1)
       0.005 migration/0/17 sched:sched_wake_idle_without_ipi(cpu: 1)
       0.011 migration/0/17 sched:sched_switch(prev_comm: "", prev_pid: 17 (migration/0), prev_state: 1, next_comm: "", next_prio: 120)
       1.173 :0/0 sched:sched_wakeup(comm: "", pid: 3138 (gnome-terminal-), prio: 120)
       1.180 :0/0 sched:sched_switch(prev_comm: "", prev_prio: 120, next_comm: "", next_pid: 3138 (gnome-terminal-), next_prio: 120)
       0.156 migration/1/21 sched:sched_migrate_task(comm: "", pid: 1603763 (perf), prio: 120, orig_cpu: 1, dest_cpu: 2)
       0.160 migration/1/21 sched:sched_wake_idle_without_ipi(cpu: 2)
       0.166 migration/1/21 sched:sched_switch(prev_comm: "", prev_pid: 21 (migration/1), prev_state: 1, next_comm: "", next_prio: 120)
       1.183 :0/0 sched:sched_wakeup(comm: "", pid: 1602985 (kworker/u16:0-f), prio: 120, target_cpu: 1)
       1.186 :0/0 sched:sched_switch(prev_comm: "", prev_prio: 120, next_comm: "", next_pid: 1602985 (kworker/u16:0-f), next_prio: 120)
  #

Had to tweak tools/perf/util/setup.py to make sure the python binding
shared object links with libtraceevent if -DHAVE_LIBTRACEEVENT is
present in CFLAGS.

Building with NO_LIBTRACEEVENT=1 uncovered some more build failures:

- Make building of data-convert-bt.c to CONFIG_LIBTRACEEVENT=y

- perf-$(CONFIG_LIBTRACEEVENT) += scripts/

- bpf_kwork.o needs also to be dependent on CONFIG_LIBTRACEEVENT=y

- The python binding needed some fixups and util/trace-event.c can't be
  built and linked with the python binding shared object, so remove it
  in tools/perf/util/setup.py and exclude it from the list of
  dependencies in the python/perf.so Makefile.perf target.

Building without libtraceevent-devel installed uncovered more build
failures:

- The python binding tools/perf/util/python.c was assuming that
  traceevent/parse-events.h was always available, which was the case
  when we defaulted to using the in-kernel tools/lib/traceevent/ files,
  now we need to enclose it under ifdef HAVE_LIBTRACEEVENT, just like
  the other parts of it that deal with tracepoints.

- We have to ifdef the rules in the Build files with
  CONFIG_LIBTRACEEVENT=y to build builtin-trace.c and
  tools/perf/trace/beauty/ as we only ifdef setting CONFIG_TRACE=y when
  setting NO_LIBTRACEEVENT=1 in the make command line, not when we don't
  detect libtraceevent-devel installed in the system. Simplification here
  to avoid these two ways of disabling builtin-trace.c and not having
  CONFIG_TRACE=y when libtraceevent-devel isn't installed is the clean
  way.

From Athira:

&lt;quote&gt;
tools/perf/arch/powerpc/util/Build
-perf-y += kvm-stat.o
+perf-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
&lt;/quote&gt;

Then, ditto for arm64 and s390, detected by container cross build tests.

- s/390 uses test__checkevent_tracepoint() that is now only available if
  HAVE_LIBTRACEEVENT is defined, enclose the callsite with ifder HAVE_LIBTRACEEVENT.

Also from Athira:

&lt;quote&gt;
With this change, I could successfully compile in these environment:
- Without libtraceevent-devel installed
- With libtraceevent-devel installed
- With “make NO_LIBTRACEEVENT=1”
&lt;/quote&gt;

Then, finally rename CONFIG_TRACEEVENT to CONFIG_LIBTRACEEVENT for
consistency with other libraries detected in tools/perf/.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Tested-by: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20221205225940.3079667-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf timechart: Add p_state_end helper</title>
<updated>2022-10-04T11:55:21+00:00</updated>
<author>
<name>Shang XiaoJing</name>
<email>shangxiaojing@huawei.com</email>
</author>
<published>2022-09-08T02:11:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3e8d21b922af782954d083d938c117b488c4578c'/>
<id>3e8d21b922af782954d083d938c117b488c4578c</id>
<content type='text'>
Wrap repeated code in helper functions p_state_end, which alloc a new
power_event recording last pstate, and insert to the head of
tchart-&gt;power_events.

Signed-off-by: Shang XiaoJing &lt;shangxiaojing@huawei.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220908021141.27134-5-shangxiaojing@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Wrap repeated code in helper functions p_state_end, which alloc a new
power_event recording last pstate, and insert to the head of
tchart-&gt;power_events.

Signed-off-by: Shang XiaoJing &lt;shangxiaojing@huawei.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220908021141.27134-5-shangxiaojing@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf timechart: Add create_pidcomm helper</title>
<updated>2022-10-04T11:55:21+00:00</updated>
<author>
<name>Shang XiaoJing</name>
<email>shangxiaojing@huawei.com</email>
</author>
<published>2022-09-08T02:11:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=569c746b8a1eab64ebf5b3ebb5d414742c8fc40b'/>
<id>569c746b8a1eab64ebf5b3ebb5d414742c8fc40b</id>
<content type='text'>
Wrap repeated code combined with alloc of per_pidcomm in helper function
create_pidcomm.

Signed-off-by: Shang XiaoJing &lt;shangxiaojing@huawei.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220908021141.27134-4-shangxiaojing@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Wrap repeated code combined with alloc of per_pidcomm in helper function
create_pidcomm.

Signed-off-by: Shang XiaoJing &lt;shangxiaojing@huawei.com&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20220908021141.27134-4-shangxiaojing@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf parse-events: Break out tracepoint and printing</title>
<updated>2022-08-02T19:32:26+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2022-07-29T20:42:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9b7c7728f4e4ba8dd75269fb111fa187faa018c6'/>
<id>9b7c7728f4e4ba8dd75269fb111fa187faa018c6</id>
<content type='text'>
Move print_*_events functions out of parse-events.c into a new
print-events.c. Move tracepoint code into tracepoint.c or
trace-event-info.c (sole user). This reduces the dependencies of
parse-events.c and makes it more amenable to being a library in the
future.

Remove some unnecessary definitions from parse-events.h. Fix a
checkpatch.pl warning on using unsigned rather than unsigned int.  Fix
some line length warnings too.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Link: https://lore.kernel.org/r/20220729204217.250166-3-irogers@google.com
[ Add include linux/stddef.h before perf_events.h for systems where __always_inline isn't pulled in before used, such as older Alpine Linux ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Move print_*_events functions out of parse-events.c into a new
print-events.c. Move tracepoint code into tracepoint.c or
trace-event-info.c (sole user). This reduces the dependencies of
parse-events.c and makes it more amenable to being a library in the
future.

Remove some unnecessary definitions from parse-events.h. Fix a
checkpatch.pl warning on using unsigned rather than unsigned int.  Fix
some line length warnings too.

Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Link: https://lore.kernel.org/r/20220729204217.250166-3-irogers@google.com
[ Add include linux/stddef.h before perf_events.h for systems where __always_inline isn't pulled in before used, such as older Alpine Linux ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Enhance the matching of sub-commands abbreviations</title>
<updated>2022-03-26T13:55:57+00:00</updated>
<author>
<name>Wei Li</name>
<email>liwei391@huawei.com</email>
</author>
<published>2022-03-25T09:20:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ae0f4eb34fc3014f7eba78fab90a0e98e441a4cd'/>
<id>ae0f4eb34fc3014f7eba78fab90a0e98e441a4cd</id>
<content type='text'>
We support short command 'rec*' for 'record' and 'rep*' for 'report' in
lots of sub-commands, but the matching is not quite strict currnetly.

It may be puzzling sometime, like we mis-type a 'recport' to report but
it will perform 'record' in fact without any message.

To fix this, add a check to ensure that the short cmd is valid prefix
of the real command.

Committer testing:

  [root@quaco ~]# perf c2c re sleep 1

   Usage: perf c2c {record|report}

      -v, --verbose         be more verbose (show counter open errors, etc)

  # perf c2c rec sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.038 MB perf.data (16 samples) ]
  # perf c2c recport sleep 1

   Usage: perf c2c {record|report}

      -v, --verbose         be more verbose (show counter open errors, etc)

  # perf c2c record sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.038 MB perf.data (15 samples) ]
  # perf c2c records sleep 1

   Usage: perf c2c {record|report}

      -v, --verbose         be more verbose (show counter open errors, etc)

  #

Signed-off-by: Wei Li &lt;liwei391@huawei.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Link: http://lore.kernel.org/lkml/20220325092032.2956161-1-liwei391@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We support short command 'rec*' for 'record' and 'rep*' for 'report' in
lots of sub-commands, but the matching is not quite strict currnetly.

It may be puzzling sometime, like we mis-type a 'recport' to report but
it will perform 'record' in fact without any message.

To fix this, add a check to ensure that the short cmd is valid prefix
of the real command.

Committer testing:

  [root@quaco ~]# perf c2c re sleep 1

   Usage: perf c2c {record|report}

      -v, --verbose         be more verbose (show counter open errors, etc)

  # perf c2c rec sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.038 MB perf.data (16 samples) ]
  # perf c2c recport sleep 1

   Usage: perf c2c {record|report}

      -v, --verbose         be more verbose (show counter open errors, etc)

  # perf c2c record sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.038 MB perf.data (15 samples) ]
  # perf c2c records sleep 1

   Usage: perf c2c {record|report}

      -v, --verbose         be more verbose (show counter open errors, etc)

  #

Signed-off-by: Wei Li &lt;liwei391@huawei.com&gt;
Tested-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Link: http://lore.kernel.org/lkml/20220325092032.2956161-1-liwei391@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Remove repipe argument from perf_session__new()</title>
<updated>2021-08-02T13:06:51+00:00</updated>
<author>
<name>Namhyung Kim</name>
<email>namhyung@kernel.org</email>
</author>
<published>2021-07-19T22:31:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2681bd85a4b92788e265934d0d76bd56b5b08d16'/>
<id>2681bd85a4b92788e265934d0d76bd56b5b08d16</id>
<content type='text'>
The repipe argument is only used by perf inject and the all others
passes 'false'.  Let's remove it from the function signature and add
__perf_session__new() to be called from perf inject directly.

This is a preparation of the change the pipe input/output.

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210719223153.1618812-2-namhyung@kernel.org
[ Fixed up some trivial conflicts as this patchset fell thru the cracks ;-( ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The repipe argument is only used by perf inject and the all others
passes 'false'.  Let's remove it from the function signature and add
__perf_session__new() to be called from perf inject directly.

This is a preparation of the change the pipe input/output.

Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Acked-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20210719223153.1618812-2-namhyung@kernel.org
[ Fixed up some trivial conflicts as this patchset fell thru the cracks ;-( ]
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Replace zero-length array with flexible-array</title>
<updated>2020-05-28T13:03:27+00:00</updated>
<author>
<name>Gustavo A. R. Silva</name>
<email>gustavoars@kernel.org</email>
</author>
<published>2020-05-15T17:29:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6549a8c0c3d94500a9a1bb66fc237f7c01c41753'/>
<id>6549a8c0c3d94500a9a1bb66fc237f7c01c41753</id>
<content type='text'>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200515172926.GA31976@embeddedor
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
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The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Gustavo A. R. Silva &lt;gustavo@embeddedor.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: http://lore.kernel.org/lkml/20200515172926.GA31976@embeddedor
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
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