#include <assert.h>
#include "compat.h"
+/* Maximum number of nesting levels for the procname cache. */
+#define PROCNAME_NESTING_MAX 2
+
/*
* We cache the result to ensure we don't trigger a system call for
* each event.
* be set for a thread before the first event is logged within this
* thread.
*/
-typedef char procname_array[17];
-static DEFINE_URCU_TLS_IE(procname_array, cached_procname);
+typedef char procname_array[PROCNAME_NESTING_MAX][17];
+
+static DEFINE_URCU_TLS(procname_array, cached_procname);
+
+static DEFINE_URCU_TLS(int, procname_nesting);
static inline
char *wrapper_getprocname(void)
{
- if (caa_unlikely(!URCU_TLS(cached_procname)[0])) {
- lttng_ust_getprocname(URCU_TLS(cached_procname));
- URCU_TLS(cached_procname)[LTTNG_UST_PROCNAME_LEN - 1] = '\0';
+ int nesting = CMM_LOAD_SHARED(URCU_TLS(procname_nesting));
+
+ if (caa_unlikely(nesting >= PROCNAME_NESTING_MAX))
+ return "<unknown>";
+ if (caa_unlikely(!URCU_TLS(cached_procname)[nesting][0])) {
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), nesting + 1);
+ /* Increment nesting before updating cache. */
+ cmm_barrier();
+ lttng_ust_getprocname(URCU_TLS(cached_procname)[nesting]);
+ URCU_TLS(cached_procname)[nesting][LTTNG_UST_PROCNAME_LEN - 1] = '\0';
+ /* Decrement nesting after updating cache. */
+ cmm_barrier();
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), nesting);
}
- return URCU_TLS(cached_procname);
+ return URCU_TLS(cached_procname)[nesting];
}
+/* Reset should not be called from a signal handler. */
void lttng_context_procname_reset(void)
{
- URCU_TLS(cached_procname)[0] = '\0';
+ CMM_STORE_SHARED(URCU_TLS(cached_procname)[1][0], '\0');
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), 1);
+ CMM_STORE_SHARED(URCU_TLS(cached_procname)[0][0], '\0');
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), 0);
}
static