On 24/08/22 01:09, Ian Rogers wrote:
> Switch to the use of mutex wrappers that provide better error checking
> for synth_lock.
It would be better to distinguish patches that make drop-in
replacements from patches like this that change logic.
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
> tools/perf/builtin-record.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 4713f0f3a6cf..02eb85677e99 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -21,6 +21,7 @@
> #include "util/evsel.h"
> #include "util/debug.h"
> #include "util/mmap.h"
> +#include "util/mutex.h"
> #include "util/target.h"
> #include "util/session.h"
> #include "util/tool.h"
> @@ -608,17 +609,18 @@ static int process_synthesized_event(struct perf_tool *tool,
> return record__write(rec, NULL, event, event->header.size);
> }
>
> +static struct mutex synth_lock;
> +
> static int process_locked_synthesized_event(struct perf_tool *tool,
> union perf_event *event,
> struct perf_sample *sample __maybe_unused,
> struct machine *machine __maybe_unused)
> {
> - static pthread_mutex_t synth_lock = PTHREAD_MUTEX_INITIALIZER;
> int ret;
>
> - pthread_mutex_lock(&synth_lock);
> + mutex_lock(&synth_lock);
> ret = process_synthesized_event(tool, event, sample, machine);
> - pthread_mutex_unlock(&synth_lock);
> + mutex_unlock(&synth_lock);
> return ret;
> }
>
> @@ -1917,6 +1919,7 @@ static int record__synthesize(struct record *rec, bool tail)
> }
>
> if (rec->opts.nr_threads_synthesize > 1) {
> + mutex_init(&synth_lock, /*pshared=*/false);
It would be better to have mutex_init() and mutex_init_shared()
since /*pshared=*/true is rarely used.
> perf_set_multithreaded();
> f = process_locked_synthesized_event;
> }
> @@ -1930,8 +1933,10 @@ static int record__synthesize(struct record *rec, bool tail)
> rec->opts.nr_threads_synthesize);
> }
>
> - if (rec->opts.nr_threads_synthesize > 1)
> + if (rec->opts.nr_threads_synthesize > 1) {
> perf_set_singlethreaded();
> + mutex_destroy(&synth_lock);
> + }
>
> out:
> return err;
