Version 2.5.7

[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 d5664c951cf708ff2b7ac6e9be4ca3b61fbbe87b..f9abadbb8f58eb1f05ee5bc22a3a49a509776b88 100644 (file)
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -25,32 +25,15 @@
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
-#include "ltt-tracer-core.h"
-
-#ifdef __linux__
-#include <syscall.h>
-#endif
-
-#if defined(_syscall0)
-_syscall0(pid_t, gettid)
-#elif defined(__NR_gettid)
-static inline pid_t gettid(void)
-{
-       return syscall(__NR_gettid);
-}
-#else
-#warning "use pid as tid"
-static inline pid_t gettid(void)
-{
-       return getpid();
-}
-#endif
+#include <lttng/ust-tid.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
@@ -59,7 +42,7 @@ static __thread pid_t cached_vtid;
  */
 void lttng_context_vtid_reset(void)
 {
-       cached_vtid = 0;
+       URCU_TLS(cached_vtid) = 0;
 }
 
 static
@@ -75,12 +58,22 @@ 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(!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,
+               union lttng_ctx_value *value)
 {
-       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();
+       value->s64 = URCU_TLS(cached_vtid);
 }
 
 int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
@@ -104,6 +97,8 @@ 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;
 }
 
@@ -112,5 +107,5 @@ 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)));
 }