perf tools: Fixup mmap event consumption

The tail position of the event buffer should only be modified after
actually use that event.

If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.

Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Zhouyi Zhou 2013-10-24 15:43:33 +08:00 committed by Arnaldo Carvalho de Melo
parent ae779a6309
commit 8e50d384cc
14 changed files with 49 additions and 16 deletions

View file

@ -78,7 +78,7 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
struct perf_sample sample;
if (event->header.type != PERF_RECORD_SAMPLE)
continue;
goto next_event;
err = perf_evlist__parse_sample(evlist, event, &sample);
if (err < 0) {
@ -88,6 +88,8 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
total_periods += sample.period;
nr_samples++;
next_event:
perf_evlist__mmap_consume(evlist, 0);
}
if ((u64) nr_samples == total_periods) {