X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=libringbuffer%2Fring_buffer_frontend.c;h=0ae3d72f23a5b16b987d5b142fcb6964bd6f0c61;hb=a025b017d398818300ad45c92284116d64c56fc1;hp=d469d04022d94e18379392189a6bd0ee55d5a4b0;hpb=2fed87aef82aaa8edfb6d8d8ac6bbf5f1e67b955;p=lttng-ust.git

diff --git a/libringbuffer/ring_buffer_frontend.c b/libringbuffer/ring_buffer_frontend.c
index d469d040..0ae3d72f 100644
--- a/libringbuffer/ring_buffer_frontend.c
+++ b/libringbuffer/ring_buffer_frontend.c
@@ -38,12 +38,14 @@
  * Dual LGPL v2.1/GPL v2 license.
  */
 
+#define _GNU_SOURCE
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <urcu/compiler.h>
 #include <urcu/ref.h>
+#include <helper.h>
 
 #include "smp.h"
 #include <lttng/ringbuffer-config.h>
@@ -51,11 +53,16 @@
 #include "backend.h"
 #include "frontend.h"
 #include "shm.h"
+#include "tlsfixup.h"
+#include "../liblttng-ust/compat.h"	/* For ENODATA */
 
 #ifndef max
 #define max(a, b)	((a) > (b) ? (a) : (b))
 #endif
 
+/* Print DBG() messages about events lost only every 1048576 hits */
+#define DBG_PRINT_NR_LOST	(1UL << 20)
+
 /*
  * Use POSIX SHM: shm_open(3) and shm_unlink(3).
  * close(2) to close the fd returned by shm_open.
@@ -91,7 +98,8 @@ __thread unsigned int lib_ring_buffer_nesting;
 static
 void lib_ring_buffer_print_errors(struct channel *chan,
 				  struct lttng_ust_lib_ring_buffer *buf, int cpu,
-				  struct lttng_ust_shm_handle *handle);
+				  struct lttng_ust_shm_handle *handle)
+	__attribute__((unused));
 
 /**
  * lib_ring_buffer_reset - Reset ring buffer to initial values.
@@ -419,7 +427,7 @@ struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buff
 		   void *buf_addr, size_t subbuf_size,
 		   size_t num_subbuf, unsigned int switch_timer_interval,
 		   unsigned int read_timer_interval,
-		   int *shm_fd, int *wait_fd, uint64_t *memory_map_size)
+		   int **shm_fd, int **wait_fd, uint64_t **memory_map_size)
 {
 	int ret, cpu;
 	size_t shmsize, chansize;
@@ -609,8 +617,8 @@ struct lttng_ust_lib_ring_buffer *channel_get_ring_buffer(
 					const struct lttng_ust_lib_ring_buffer_config *config,
 					struct channel *chan, int cpu,
 					struct lttng_ust_shm_handle *handle,
-					int *shm_fd, int *wait_fd,
-					uint64_t *memory_map_size)
+					int **shm_fd, int **wait_fd,
+					uint64_t **memory_map_size)
 {
 	struct shm_ref *ref;
 
@@ -945,12 +953,6 @@ void lib_ring_buffer_print_buffer_errors(struct lttng_ust_lib_ring_buffer *buf,
 	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
 	unsigned long write_offset, cons_offset;
 
-	/*
-	 * Can be called in the error path of allocation when
-	 * trans_channel_data is not yet set.
-	 */
-	if (!chan)
-		return;
 	/*
 	 * No need to order commit_count, write_offset and cons_offset reads
 	 * because we execute at teardown when no more writer nor reader
@@ -1339,11 +1341,19 @@ int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
 				 - subbuf_trunc((unsigned long)
 				     uatomic_read(&buf->consumed), chan)
 				>= chan->backend.buf_size)) {
+				unsigned long nr_lost;
+
 				/*
 				 * We do not overwrite non consumed buffers
 				 * and we are full : record is lost.
 				 */
+				nr_lost = v_read(config, &buf->records_lost_full);
 				v_inc(config, &buf->records_lost_full);
+				if ((nr_lost & (DBG_PRINT_NR_LOST - 1)) == 0) {
+					DBG("%lu or more records lost in (%s:%d) (buffer full)\n",
+						nr_lost + 1, chan->backend.name,
+						buf->backend.cpu);
+				}
 				return -ENOBUFS;
 			} else {
 				/*
@@ -1354,13 +1364,21 @@ int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
 				 */
 			}
 		} else {
+			unsigned long nr_lost;
+
 			/*
 			 * Next subbuffer reserve offset does not match the
 			 * commit offset. Drop record in producer-consumer and
 			 * overwrite mode. Caused by either a writer OOPS or too
 			 * many nested writes over a reserve/commit pair.
 			 */
+			nr_lost = v_read(config, &buf->records_lost_wrap);
 			v_inc(config, &buf->records_lost_wrap);
+			if ((nr_lost & (DBG_PRINT_NR_LOST - 1)) == 0) {
+				DBG("%lu or more records lost in (%s:%d) (wrap-around)\n",
+					nr_lost + 1, chan->backend.name,
+					buf->backend.cpu);
+			}
 			return -EIO;
 		}
 		offsets->size =
@@ -1374,11 +1392,20 @@ int lib_ring_buffer_try_reserve_slow(struct lttng_ust_lib_ring_buffer *buf,
 			+ ctx->data_size;
 		if (caa_unlikely(subbuf_offset(offsets->begin, chan)
 			     + offsets->size > chan->backend.subbuf_size)) {
+			unsigned long nr_lost;
+
 			/*
 			 * Record too big for subbuffers, report error, don't
 			 * complete the sub-buffer switch.
 			 */
+			nr_lost = v_read(config, &buf->records_lost_big);
 			v_inc(config, &buf->records_lost_big);
+			if ((nr_lost & (DBG_PRINT_NR_LOST - 1)) == 0) {
+				DBG("%lu or more records lost in (%s:%d) record size "
+					" of %zu bytes is too large for buffer\n",
+					nr_lost + 1, chan->backend.name,
+					buf->backend.cpu, offsets->size);
+			}
 			return -ENOSPC;
 		} else {
 			/*
@@ -1482,3 +1509,11 @@ int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
 	ctx->buf_offset = offsets.begin + offsets.pre_header_padding;
 	return 0;
 }
+
+/*
+ * Force a read (imply TLS fixup for dlopen) of TLS variables.
+ */
+void lttng_fixup_ringbuffer_tls(void)
+{
+	asm volatile ("" : : "m" (lib_ring_buffer_nesting));
+}