Use initial-exec TLS model

[lttng-ust.git] / liblttng-ust / lttng-context-vtid.c

diff --git a/liblttng-ust/lttng-context-vtid.c b/liblttng-ust/lttng-context-vtid.c
index 4b1da4f8e9b78541473f3e838352e04ac4461679..8c9bbec56e67324bdaeeca71893197a58b571f38 100644 (file)
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -20,6 +20,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#define _LGPL_SOURCE
 #include <sys/types.h>
 #include <unistd.h>
 #include <lttng/ust-events.h>
@@ -33,7 +34,7 @@
  * We cache the result to ensure we don't trigger a system call for
  * each event.
  */
-static DEFINE_URCU_TLS(pid_t, cached_vtid);
+static DEFINE_URCU_TLS_IE(pid_t, cached_vtid);
 
 /*
  * Upon fork or clone, the TID assigned to our thread is not the same as
@@ -46,7 +47,7 @@ void lttng_context_vtid_reset(void)
 }
 
 static
-size_t vtid_get_size(size_t offset)
+size_t vtid_get_size(struct lttng_ctx_field *field, size_t offset)
 {
        size_t size = 0;
 
@@ -67,6 +68,15 @@ void vtid_record(struct lttng_ctx_field *field,
                sizeof(URCU_TLS(cached_vtid)));
 }
 
+static
+void vtid_get_value(struct lttng_ctx_field *field,
+               struct lttng_ctx_value *value)
+{
+       if (caa_unlikely(!URCU_TLS(cached_vtid)))
+               URCU_TLS(cached_vtid) = gettid();
+       value->u.s64 = URCU_TLS(cached_vtid);
+}
+
 int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
 {
        struct lttng_ctx_field *field;
@@ -88,6 +98,8 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
        field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
        field->get_size = vtid_get_size;
        field->record = vtid_record;
+       field->get_value = vtid_get_value;
+       lttng_context_update(*ctx);
        return 0;
 }