Revert "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 81508515ba56c3dee817c92f34b4c5513a3df444..f28e470a38c91be3e88c7b1d1fcd42c591d73c67 100644 (file)
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -20,19 +20,21 @@
  * 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>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
 #include <lttng/ust-tid.h>
-#include "ltt-tracer-core.h"
+#include <urcu/tls-compat.h>
+#include "lttng-tracer-core.h"
 
 /*
  * We cache the result to ensure we don't trigger a system call for
  * each event.
  */
-static __thread pid_t cached_vtid;
+static DEFINE_URCU_TLS(pid_t, cached_vtid);
 
 /*
  * Upon fork or clone, the TID assigned to our thread is not the same as
@@ -41,11 +43,11 @@ static __thread pid_t cached_vtid;
  */
 void lttng_context_vtid_reset(void)
 {
-       cached_vtid = 0;
+       URCU_TLS(cached_vtid) = 0;
 }
 
 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;
 
@@ -57,12 +59,22 @@ size_t vtid_get_size(size_t offset)
 static
 void vtid_record(struct lttng_ctx_field *field,
                 struct lttng_ust_lib_ring_buffer_ctx *ctx,
-                struct ltt_channel *chan)
+                struct lttng_channel *chan)
 {
-       if (caa_unlikely(!cached_vtid))
-               cached_vtid = gettid();
-       lib_ring_buffer_align_ctx(ctx, lttng_alignof(cached_vtid));
-       chan->ops->event_write(ctx, &cached_vtid, sizeof(cached_vtid));
+       if (caa_unlikely(!URCU_TLS(cached_vtid)))
+               URCU_TLS(cached_vtid) = gettid();
+       lib_ring_buffer_align_ctx(ctx, lttng_alignof(URCU_TLS(cached_vtid)));
+       chan->ops->event_write(ctx, &URCU_TLS(cached_vtid),
+               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)
@@ -86,6 +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;
 }
 
@@ -94,5 +108,5 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
  */
 void lttng_fixup_vtid_tls(void)
 {
-       asm volatile ("" : : "m" (cached_vtid));
+       asm volatile ("" : : "m" (URCU_TLS(cached_vtid)));
 }