Add license info about lib/ringbuffer/ring_buffer_mmap.c being GPLv2

[lttng-modules.git] / ltt-ring-buffer-client.h

diff --git a/ltt-ring-buffer-client.h b/ltt-ring-buffer-client.h
index 0d8051ece35bd5ec2e42e3641524b1c5c6a993fb..904c42eb466b68e8745f1108ad50922460ba4980 100644 (file)
--- a/ltt-ring-buffer-client.h
+++ b/ltt-ring-buffer-client.h
@@ -22,6 +22,14 @@
  * you ever add/remove a field from this header. Packed attribute is not used
  * because gcc generates poor code on at least powerpc and mips. Don't ever
  * let gcc add padding between the structure elements.
+ *
+ * The guarantee we have with timestamps is that all the events in a
+ * packet are included (inclusive) within the begin/end timestamps of
+ * the packet. Another guarantee we have is that the "timestamp begin",
+ * as well as the event timestamps, are monotonically increasing (never
+ * decrease) when moving forward in a stream (physically). But this
+ * guarantee does not apply to "timestamp end", because it is sampled at
+ * commit time, which is not ordered with respect to space reservation.
  */
 
 struct packet_header {
@@ -137,6 +145,7 @@ unsigned char record_header_size(const struct lib_ring_buffer_config *config,
                }
                break;
        default:
+               padding = 0;
                WARN_ON_ONCE(1);
        }
        offset += ctx_get_size(offset, event->ctx);
@@ -148,7 +157,7 @@ unsigned char record_header_size(const struct lib_ring_buffer_config *config,
 
 #include "wrapper/ringbuffer/api.h"
 
-extern
+static
 void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
                                 struct lib_ring_buffer_ctx *ctx,
                                 uint32_t event_id);
@@ -197,8 +206,8 @@ void ltt_write_event_header(const struct lib_ring_buffer_config *config,
                WARN_ON_ONCE(1);
        }
 
-       ctx_record(ctx, ltt_chan, event->ctx);
        ctx_record(ctx, ltt_chan, ltt_chan->ctx);
+       ctx_record(ctx, ltt_chan, event->ctx);
 
        return;
 
@@ -206,6 +215,7 @@ slow_path:
        ltt_write_event_header_slow(config, ctx, event_id);
 }
 
+static
 void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
                                 struct lib_ring_buffer_ctx *ctx,
                                 uint32_t event_id)
@@ -259,8 +269,8 @@ void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
        default:
                WARN_ON_ONCE(1);
        }
-       ctx_record(ctx, ltt_chan, event->ctx);
        ctx_record(ctx, ltt_chan, ltt_chan->ctx);
+       ctx_record(ctx, ltt_chan, event->ctx);
 }
 
 static const struct lib_ring_buffer_config client_config;
@@ -361,7 +371,7 @@ static const struct lib_ring_buffer_config client_config = {
        .sync = RING_BUFFER_SYNC_PER_CPU,
        .mode = RING_BUFFER_MODE_TEMPLATE,
        .backend = RING_BUFFER_PAGE,
-       .output = RING_BUFFER_SPLICE,
+       .output = RING_BUFFER_OUTPUT_TEMPLATE,
        .oops = RING_BUFFER_OOPS_CONSISTENCY,
        .ipi = RING_BUFFER_IPI_BARRIER,
        .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
@@ -399,6 +409,20 @@ struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
        return NULL;
 }
 
+static
+int ltt_buffer_has_read_closed_stream(struct channel *chan)
+{
+       struct lib_ring_buffer *buf;
+       int cpu;
+
+       for_each_channel_cpu(cpu, chan) {
+               buf = channel_get_ring_buffer(&client_config, chan, cpu);
+               if (!atomic_long_read(&buf->active_readers))
+                       return 1;
+       }
+       return 0;
+}
+
 static
 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 {
@@ -485,6 +509,8 @@ static struct ltt_transport ltt_relay_transport = {
                .channel_create = _channel_create,
                .channel_destroy = ltt_channel_destroy,
                .buffer_read_open = ltt_buffer_read_open,
+               .buffer_has_read_closed_stream =
+                       ltt_buffer_has_read_closed_stream,
                .buffer_read_close = ltt_buffer_read_close,
                .event_reserve = ltt_event_reserve,
                .event_commit = ltt_event_commit,
@@ -504,7 +530,6 @@ static int __init ltt_ring_buffer_client_init(void)
         * vmalloc'd module pages when it is built as a module into LTTng.
         */
        wrapper_vmalloc_sync_all();
-       printk(KERN_INFO "LTT : ltt ring buffer client init\n");
        ltt_transport_register(&ltt_relay_transport);
        return 0;
 }
@@ -513,7 +538,6 @@ module_init(ltt_ring_buffer_client_init);
 
 static void __exit ltt_ring_buffer_client_exit(void)
 {
-       printk(KERN_INFO "LTT : ltt ring buffer client exit\n");
        ltt_transport_unregister(&ltt_relay_transport);
 }