perf record: Turns auxtrace_snapshot_enable into 3 states

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>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1460535673-159866-4-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index eb6a199..480033f 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -125,7 +125,43 @@ 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;
 
@@ -249,7 +285,7 @@ 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();
        }
 }
 
@@ -615,10 +651,13 @@ 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) {
@@ -744,12 +783,12 @@ 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;
                }
@@ -787,12 +826,12 @@ 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];
@@ -1358,9 +1397,9 @@ 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;
 }