[PATCH 21/46] perf record: Turns auxtrace_snapshot_enable into 3 states

Wang Nan
2016-02-26T09:49:06Z

auxtrace_snapshot_enable has only two states (0/1). Turns it into a
triple states enum so SIGUSR2 handler can safely do other works without
triggering auxtrace snapshot.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: He Kuang <hekuang@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
---
tools/perf/builtin-record.c | 59 +++++++++++++++++++++++++++++++++++++--------
1 file changed, 49 insertions(+), 10 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index cb583b4..6257fd7 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -124,7 +124,43 @@ out:
static volatile int done;
static volatile int signr = -1;
static volatile int child_finished;
-static volatile int auxtrace_snapshot_enabled;
+
+static volatile enum {
+ AUXTRACE_SNAPSHOT_OFF = -1,
+ AUXTRACE_SNAPSHOT_DISABLED = 0,
+ AUXTRACE_SNAPSHOT_ENABLED = 1,
+} auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_OFF;
+
+static inline void
+auxtrace_snapshot_on(void)
+{
+ auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_DISABLED;
+}
+
+static inline void
+auxtrace_snapshot_enable(void)
+{
+ if (auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_OFF)
+ return;
+ auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_ENABLED;
+}
+
+static inline void
+auxtrace_snapshot_disable(void)
+{
+ if (auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_OFF)
+ return;
+ auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_DISABLED;
+}
+
+static inline bool
+auxtrace_snapshot_is_enabled(void)
+{
+ if (auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_OFF)
+ return false;
+ return auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_ENABLED;
+}
+
static volatile int auxtrace_snapshot_err;
static volatile int auxtrace_record__snapshot_started;

@@ -248,7 +284,7 @@ static void record__read_auxtrace_snapshot(struct record *rec)
} else {
auxtrace_snapshot_err = auxtrace_record__snapshot_finish(rec->itr);
if (!auxtrace_snapshot_err)
- auxtrace_snapshot_enabled = 1;
+ auxtrace_snapshot_enable();
}
}

@@ -574,10 +610,13 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
- if (rec->opts.auxtrace_snapshot_mode)
+
+ if (rec->opts.auxtrace_snapshot_mode) {
signal(SIGUSR2, snapshot_sig_handler);
- else
+ auxtrace_snapshot_on();
+ } else {
signal(SIGUSR2, SIG_IGN);
+ }

session = perf_session__new(file, false, tool);
if (session == NULL) {
@@ -703,12 +742,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
perf_evlist__enable(rec->evlist);
}

- auxtrace_snapshot_enabled = 1;
+ auxtrace_snapshot_enable();
for (;;) {
unsigned long long hits = rec->samples;

if (record__mmap_read_all(rec) < 0) {
- auxtrace_snapshot_enabled = 0;
+ auxtrace_snapshot_disable();
err = -1;
goto out_child;
}
@@ -746,12 +785,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
* disable events in this case.
*/
if (done && !disabled && !target__none(&opts->target)) {
- auxtrace_snapshot_enabled = 0;
+ auxtrace_snapshot_disable();
perf_evlist__disable(rec->evlist);
disabled = true;
}
}
- auxtrace_snapshot_enabled = 0;
+ auxtrace_snapshot_disable();

if (forks && workload_exec_errno) {
char msg[STRERR_BUFSIZE];
@@ -1319,9 +1358,9 @@ out_symbol_exit:

static void snapshot_sig_handler(int sig __maybe_unused)
{
- if (!auxtrace_snapshot_enabled)
+ if (!auxtrace_snapshot_is_enabled())
return;
- auxtrace_snapshot_enabled = 0;
+ auxtrace_snapshot_disable();
auxtrace_snapshot_err = auxtrace_record__snapshot_start(record.itr);
auxtrace_record__snapshot_started = 1;
}
--
1.8.3.4