fork: don't switch buffer when destroying trace in child

If we do switch the buffer, it switches the parent's buffer, because the both
process' buffers are still the same. This is undesirable. So we add a special
"drop" mode to ltt_trace_destroy.

diff --git a/libust/tracectl.c b/libust/tracectl.c
index 3cb86edc80180f535e8a5773d8413ee11032db64..c72d013d7535a5539960e4d111ad24b39bcc6e54 100644 (file)
--- a/libust/tracectl.c
+++ b/libust/tracectl.c
@@ -964,7 +964,7 @@ void *listener_main(void *p)
 
                        DBG("trace destroy");
 
-                       result = ltt_trace_destroy(trace_name);
+                       result = ltt_trace_destroy(trace_name, 0);
                        if(result < 0) {
                                ERR("ltt_trace_destroy failed");
                                return (void *)1;
@@ -1348,7 +1348,7 @@ static void destroy_traces(void)
                ERR("ltt_trace_stop error");
        }
 
-       result = ltt_trace_destroy("auto");
+       result = ltt_trace_destroy("auto", 0);
        if(result == -1) {
                ERR("ltt_trace_destroy error");
        }
@@ -1453,9 +1453,10 @@ static void ust_fork(void)
        struct blocked_consumer *deletable_bc = NULL;
        int result;
 
+       /* FIXME: technically, the locks could have been taken before the fork */
        DBG("ust: forking");
        ltt_trace_stop("auto");
-       ltt_trace_destroy("auto");
+       ltt_trace_destroy("auto", 1);
        /* Delete all active connections */
        ustcomm_close_all_connections(&ustcomm_app.server);
 

diff --git a/libust/tracer.c b/libust/tracer.c
index 52928b836ba290c9d67d1ce45cc63377b32ba693..5f9aa69ffe2d8531f1c88bed35eb910b82b709ae 100644 (file)
--- a/libust/tracer.c
+++ b/libust/tracer.c
@@ -784,15 +784,17 @@ traces_error:
 }
 
 /* Sleepable part of the destroy */
-static void __ltt_trace_destroy(struct ust_trace *trace)
+static void __ltt_trace_destroy(struct ust_trace *trace, int drop)
 {
        int i;
        struct ust_channel *chan;
 
-       for (i = 0; i < trace->nr_channels; i++) {
-               chan = &trace->channels[i];
-               if (chan->active)
-                       trace->ops->finish_channel(chan);
+       if(!drop) {
+               for (i = 0; i < trace->nr_channels; i++) {
+                       chan = &trace->channels[i];
+                       if (chan->active)
+                               trace->ops->finish_channel(chan);
+               }
        }
 
        return; /* FIXME: temporary for ust */
@@ -827,7 +829,7 @@ static void __ltt_trace_destroy(struct ust_trace *trace)
        kref_put(&trace->kref, ltt_release_trace);
 }
 
-int ltt_trace_destroy(const char *trace_name)
+int ltt_trace_destroy(const char *trace_name, int drop)
 {
        int err = 0;
        struct ust_trace *trace;
@@ -842,7 +844,7 @@ int ltt_trace_destroy(const char *trace_name)
 
                ltt_unlock_traces();
 
-               __ltt_trace_destroy(trace);
+               __ltt_trace_destroy(trace, drop);
 //ust//                put_trace_clock();
 
                return 0;

diff --git a/libust/tracer.h b/libust/tracer.h
index 614d7b2c2877b32703296ec40cbe9506017cf551..cc3974e2a9d45ef0febc077b153ffa7637fe2ad3 100644 (file)
--- a/libust/tracer.h
+++ b/libust/tracer.h
@@ -385,7 +385,7 @@ extern int ltt_trace_set_channel_enable(const char *trace_name,
 extern int ltt_trace_set_channel_overwrite(const char *trace_name,
                const char *channel_name, unsigned int overwrite);
 extern int ltt_trace_alloc(const char *trace_name);
-extern int ltt_trace_destroy(const char *trace_name);
+extern int ltt_trace_destroy(const char *trace_name, int drop);
 extern int ltt_trace_start(const char *trace_name);
 extern int ltt_trace_stop(const char *trace_name);
 

diff --git a/tests/hello/hello.c b/tests/hello/hello.c
index 561d92e464d7f00871a97f42265a190a4c0ee141..5db487b05a1503040865102e34565b8427f0a932 100644 (file)
--- a/tests/hello/hello.c
+++ b/tests/hello/hello.c
@@ -63,7 +63,7 @@ int main()
        scanf("%*s");
 
        ltt_trace_stop("auto");
-       ltt_trace_destroy("auto");
+       ltt_trace_destroy("auto", 0);
 
        DBG("TRACE STOPPED");
        scanf("%*s");