Searched hist:"5141 d735" (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/tools/perf/util/ |
| H A D | data-convert-bt.c | 5141d735 Fri Feb 05 08:01:30 CST 2016 Wang Nan <wangnan0@huawei.com> perf data: Fix releasing event_class
A new patch in libbabeltrace [1] reveals a object leak problem in
'perf data' CTF support: perf code never releases the event_class
which is allocated in add_event() and stored in evsel's private field.
If libbabeltrace has the above patch applied, leaking event_class
prevents the writer from being destroyed and flushing metadata. For
example:
$ perf record ls
perf.data
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data (12 samples) ]
$ perf data convert --to-ctf ./out.ctf
[ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ]
[ perf data convert: Converted and wrote 0.000 MB (12 samples) ]
$ cat ./out.ctf/metadata
$ ls -l ./out.ctf/metadata
-rw-r----- 1 w00229757 mm 0 Jan 27 10:49 ./out.ctf/metadata
The correct result should be:
...
$ cat ./out.ctf/metadata
/* CTF 1.8 */
trace {
[SNIP]
$ ls -l ./out.ctf/metadata
-rw-r----- 1 w00229757 mm 2446 Jan 27 10:52 ./out.ctf/metadata
The full story is:
Patch [1] of babeltrace redesigns its reference counting scheme. In that
patch:
* writer <- trace (bt_ctf_writer_create)
* trace <- stream_class (bt_ctf_trace_add_stream_class)
* stream_class <- event_class (bt_ctf_stream_class_add_event_class)
('<-' means 'is a parent of')
Holding of event_class causes reference count of corresponding 'writer'
to increase through parent chain. Perf expects that 'writer' is released
(so metadata is flushed) through bt_ctf_writer_put() in
ctf_writer__cleanup(). However, since it never releases event_class, the
reference of 'writer' won't be dropped, so bt_ctf_writer_put() won't
lead to the release of writer.
Before this CTF patch, !(writer <- trace). Even with event_class leaking,
the writer ends up being released.
[1] https://github.com/efficios/babeltrace/commit/e6a8e8e4744633807083a077ff9f101eb97d9801
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1454680939-24963-6-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
5141d735 Fri Feb 05 08:01:30 CST 2016 Wang Nan <wangnan0@huawei.com> perf data: Fix releasing event_class
A new patch in libbabeltrace [1] reveals a object leak problem in
'perf data' CTF support: perf code never releases the event_class
which is allocated in add_event() and stored in evsel's private field.
If libbabeltrace has the above patch applied, leaking event_class
prevents the writer from being destroyed and flushing metadata. For
example:
$ perf record ls
perf.data
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data (12 samples) ]
$ perf data convert --to-ctf ./out.ctf
[ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ]
[ perf data convert: Converted and wrote 0.000 MB (12 samples) ]
$ cat ./out.ctf/metadata
$ ls -l ./out.ctf/metadata
-rw-r----- 1 w00229757 mm 0 Jan 27 10:49 ./out.ctf/metadata
The correct result should be:
...
$ cat ./out.ctf/metadata
/* CTF 1.8 */
trace {
[SNIP]
$ ls -l ./out.ctf/metadata
-rw-r----- 1 w00229757 mm 2446 Jan 27 10:52 ./out.ctf/metadata
The full story is:
Patch [1] of babeltrace redesigns its reference counting scheme. In that
patch:
* writer <- trace (bt_ctf_writer_create)
* trace <- stream_class (bt_ctf_trace_add_stream_class)
* stream_class <- event_class (bt_ctf_stream_class_add_event_class)
('<-' means 'is a parent of')
Holding of event_class causes reference count of corresponding 'writer'
to increase through parent chain. Perf expects that 'writer' is released
(so metadata is flushed) through bt_ctf_writer_put() in
ctf_writer__cleanup(). However, since it never releases event_class, the
reference of 'writer' won't be dropped, so bt_ctf_writer_put() won't
lead to the release of writer.
Before this CTF patch, !(writer <- trace). Even with event_class leaking,
the writer ends up being released.
[1] https://github.com/efficios/babeltrace/commit/e6a8e8e4744633807083a077ff9f101eb97d9801
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1454680939-24963-6-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|