Fix: dmesg printout should not print metadata warnings

[lttng-ust.git] / libringbuffer / ring_buffer_frontend.c

diff --git a/libringbuffer/ring_buffer_frontend.c b/libringbuffer/ring_buffer_frontend.c
index d0649f3e36b9e33b0e1b247854fd6a2c000f714a..6d4a21bac101d0cfbc2809c4fce3a8489cdc1b41 100644 (file)
--- a/libringbuffer/ring_buffer_frontend.c
+++ b/libringbuffer/ring_buffer_frontend.c
@@ -38,6 +38,7 @@
  * Dual LGPL v2.1/GPL v2 license.
  */
 
+#define _GNU_SOURCE
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
@@ -52,11 +53,15 @@
 #include "backend.h"
 #include "frontend.h"
 #include "shm.h"
+#include "tlsfixup.h"
 
 #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.
@@ -92,7 +97,8 @@ __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.
@@ -976,23 +982,30 @@ void lib_ring_buffer_print_errors(struct channel *chan,
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
        void *priv = channel_get_private(chan);
 
-       DBG("ring buffer %s, cpu %d: %lu records written, "
-                         "%lu records overrun\n",
-                         chan->backend.name, cpu,
-                         v_read(config, &buf->records_count),
-                         v_read(config, &buf->records_overrun));
-
-       if (v_read(config, &buf->records_lost_full)
-           || v_read(config, &buf->records_lost_wrap)
-           || v_read(config, &buf->records_lost_big))
-               DBG("ring buffer %s, cpu %d: records were lost. Caused by:\n"
-                      "  [ %lu buffer full, %lu nest buffer wrap-around, "
-                      "%lu event too big ]\n",
-                      chan->backend.name, cpu,
-                      v_read(config, &buf->records_lost_full),
-                      v_read(config, &buf->records_lost_wrap),
-                      v_read(config, &buf->records_lost_big));
-
+       if (!strcmp(chan->backend.name, "relay-metadata-mmap")) {
+               DBG("ring buffer %s: %lu records written, "
+                       "%lu records overrun\n",
+                       chan->backend.name,
+                       v_read(config, &buf->records_count),
+                       v_read(config, &buf->records_overrun));
+       } else {
+               DBG("ring buffer %s, cpu %d: %lu records written, "
+                       "%lu records overrun\n",
+                       chan->backend.name, cpu,
+                       v_read(config, &buf->records_count),
+                       v_read(config, &buf->records_overrun));
+
+               if (v_read(config, &buf->records_lost_full)
+                   || v_read(config, &buf->records_lost_wrap)
+                   || v_read(config, &buf->records_lost_big))
+                       DBG("ring buffer %s, cpu %d: records were lost. Caused by:\n"
+                               "  [ %lu buffer full, %lu nest buffer wrap-around, "
+                               "%lu event too big ]\n",
+                               chan->backend.name, cpu,
+                               v_read(config, &buf->records_lost_full),
+                               v_read(config, &buf->records_lost_wrap),
+                               v_read(config, &buf->records_lost_big));
+       }
        lib_ring_buffer_print_buffer_errors(buf, chan, priv, cpu, handle);
 }
 
@@ -1334,11 +1347,19 @@ 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 {
                                /*
@@ -1349,13 +1370,21 @@ 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 =
@@ -1369,11 +1398,20 @@ 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 {
                        /*
@@ -1477,3 +1515,11 @@ 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));
+}