X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_frontend.c;h=74b77acc8ef2abde1984a53843f5ab4bebeff7fc;hb=360d3efee55154a55c18be32175bee608dcb21df;hp=27e871e42a2ef13956412b3cecd6c69e9faed607;hpb=df93abe8f183251659200d95429dc67e8cfe8e4a;p=lttng-modules.git

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index 27e871e4..74b77acc 100644
--- a/lib/ringbuffer/ring_buffer_frontend.c
+++ b/lib/ringbuffer/ring_buffer_frontend.c
@@ -150,6 +150,7 @@ void lib_ring_buffer_free(struct lib_ring_buffer *buf)
 	lib_ring_buffer_print_errors(chan, buf, buf->backend.cpu);
 	lttng_kvfree(buf->commit_hot);
 	lttng_kvfree(buf->commit_cold);
+	lttng_kvfree(buf->ts_end);
 
 	lib_ring_buffer_backend_free(&buf->backend);
 }
@@ -179,6 +180,7 @@ void lib_ring_buffer_reset(struct lib_ring_buffer *buf)
 		v_set(config, &buf->commit_hot[i].cc, 0);
 		v_set(config, &buf->commit_hot[i].seq, 0);
 		v_set(config, &buf->commit_cold[i].cc_sb, 0);
+		buf->ts_end[i] = 0;
 	}
 	atomic_long_set(&buf->consumed, 0);
 	atomic_set(&buf->record_disabled, 0);
@@ -267,6 +269,17 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
 		goto free_commit;
 	}
 
+	buf->ts_end =
+		lttng_kvzalloc_node(ALIGN(sizeof(*buf->ts_end)
+				   * chan->backend.num_subbuf,
+				   1 << INTERNODE_CACHE_SHIFT),
+			GFP_KERNEL | __GFP_NOWARN,
+			cpu_to_node(max(cpu, 0)));
+	if (!buf->ts_end) {
+		ret = -ENOMEM;
+		goto free_commit_cold;
+	}
+
 	init_waitqueue_head(&buf->read_wait);
 	init_waitqueue_head(&buf->write_wait);
 	raw_spin_lock_init(&buf->raw_tick_nohz_spinlock);
@@ -306,6 +319,8 @@ int lib_ring_buffer_create(struct lib_ring_buffer *buf,
 
 	/* Error handling */
 free_init:
+	lttng_kvfree(buf->ts_end);
+free_commit_cold:
 	lttng_kvfree(buf->commit_cold);
 free_commit:
 	lttng_kvfree(buf->commit_hot);
@@ -406,7 +421,7 @@ static void lib_ring_buffer_start_read_timer(struct lib_ring_buffer *buf)
 {
 	struct channel *chan = buf->backend.chan;
 	const struct lib_ring_buffer_config *config = &chan->backend.config;
-	unsigned int flags;
+	unsigned int flags = 0;
 
 	if (config->wakeup != RING_BUFFER_WAKEUP_BY_TIMER
 	    || !chan->read_timer_interval
@@ -452,7 +467,7 @@ static void lib_ring_buffer_stop_read_timer(struct lib_ring_buffer *buf)
 	buf->read_timer_enabled = 0;
 }
 
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
 
 enum cpuhp_state lttng_rb_hp_prepare;
 enum cpuhp_state lttng_rb_hp_online;
@@ -523,7 +538,7 @@ int lttng_cpuhp_rb_frontend_offline(unsigned int cpu,
 }
 EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_frontend_offline);
 
-#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 
 #ifdef CONFIG_HOTPLUG_CPU
 
@@ -585,7 +600,7 @@ int lib_ring_buffer_cpu_hp_callback(struct notifier_block *nb,
 
 #endif
 
-#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 
 #if defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER)
 /*
@@ -691,7 +706,7 @@ static void channel_unregister_notifiers(struct channel *chan)
 		 * concurrency.
 		 */
 #endif /* CONFIG_NO_HZ */
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
 		{
 			int ret;
 
@@ -702,7 +717,7 @@ static void channel_unregister_notifiers(struct channel *chan)
 				&chan->cpuhp_prepare.node);
 			WARN_ON(ret);
 		}
-#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 		{
 			int cpu;
 
@@ -726,7 +741,7 @@ static void channel_unregister_notifiers(struct channel *chan)
 			}
 #endif
 		}
-#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 	} else {
 		struct lib_ring_buffer *buf = chan->backend.buf;
 
@@ -855,7 +870,7 @@ struct channel *channel_create(const struct lib_ring_buffer_config *config,
 	init_waitqueue_head(&chan->hp_wait);
 
 	if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
 		chan->cpuhp_prepare.component = LTTNG_RING_BUFFER_FRONTEND;
 		ret = cpuhp_state_add_instance_nocalls(lttng_rb_hp_prepare,
 			&chan->cpuhp_prepare.node);
@@ -867,7 +882,7 @@ struct channel *channel_create(const struct lib_ring_buffer_config *config,
 			&chan->cpuhp_online.node);
 		if (ret)
 			goto cpuhp_online_error;
-#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 		{
 			int cpu;
 			/*
@@ -903,7 +918,7 @@ struct channel *channel_create(const struct lib_ring_buffer_config *config,
 			}
 #endif
 		}
-#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 
 #if defined(CONFIG_NO_HZ) && defined(CONFIG_LIB_RING_BUFFER)
 		/* Only benefit from NO_HZ idle with per-cpu buffers for now. */
@@ -923,13 +938,13 @@ struct channel *channel_create(const struct lib_ring_buffer_config *config,
 
 	return chan;
 
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
 cpuhp_online_error:
 	ret = cpuhp_state_remove_instance_nocalls(lttng_rb_hp_prepare,
 			&chan->cpuhp_prepare.node);
 	WARN_ON(ret);
 cpuhp_prepare_error:
-#endif /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+#endif /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
 error_free_backend:
 	channel_backend_free(&chan->backend);
 error:
@@ -977,13 +992,11 @@ void *channel_destroy(struct channel *chan)
 				config->cb.buffer_finalize(buf,
 							   chan->backend.priv,
 							   cpu);
-			if (buf->backend.allocated)
-				lib_ring_buffer_set_quiescent(buf);
 			/*
 			 * Perform flush before writing to finalized.
 			 */
 			smp_wmb();
-			ACCESS_ONCE(buf->finalized) = 1;
+			WRITE_ONCE(buf->finalized, 1);
 			wake_up_interruptible(&buf->read_wait);
 		}
 	} else {
@@ -991,16 +1004,14 @@ void *channel_destroy(struct channel *chan)
 
 		if (config->cb.buffer_finalize)
 			config->cb.buffer_finalize(buf, chan->backend.priv, -1);
-		if (buf->backend.allocated)
-			lib_ring_buffer_set_quiescent(buf);
 		/*
 		 * Perform flush before writing to finalized.
 		 */
 		smp_wmb();
-		ACCESS_ONCE(buf->finalized) = 1;
+		WRITE_ONCE(buf->finalized, 1);
 		wake_up_interruptible(&buf->read_wait);
 	}
-	ACCESS_ONCE(chan->finalized) = 1;
+	WRITE_ONCE(chan->finalized, 1);
 	wake_up_interruptible(&chan->hp_wait);
 	wake_up_interruptible(&chan->read_wait);
 	priv = chan->backend.priv;
@@ -1077,7 +1088,7 @@ int lib_ring_buffer_snapshot(struct lib_ring_buffer *buf,
 	int finalized;
 
 retry:
-	finalized = ACCESS_ONCE(buf->finalized);
+	finalized = READ_ONCE(buf->finalized);
 	/*
 	 * Read finalized before counters.
 	 */
@@ -1248,7 +1259,7 @@ int lib_ring_buffer_get_subbuf(struct lib_ring_buffer *buf,
 		return -EBUSY;
 	}
 retry:
-	finalized = ACCESS_ONCE(buf->finalized);
+	finalized = READ_ONCE(buf->finalized);
 	/*
 	 * Read finalized before counters.
 	 */
@@ -1501,12 +1512,13 @@ void lib_ring_buffer_print_buffer_errors(struct lib_ring_buffer *buf,
 						       cpu);
 }
 
+#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS
 static
-void lib_ring_buffer_print_errors(struct channel *chan,
-				  struct lib_ring_buffer *buf, int cpu)
+void lib_ring_buffer_print_records_count(struct channel *chan,
+					 struct lib_ring_buffer *buf,
+					 int cpu)
 {
 	const struct lib_ring_buffer_config *config = &chan->backend.config;
-	void *priv = chan->backend.priv;
 
 	if (!strcmp(chan->backend.name, "relay-metadata")) {
 		printk(KERN_DEBUG "ring buffer %s: %lu records written, "
@@ -1520,7 +1532,26 @@ void lib_ring_buffer_print_errors(struct channel *chan,
 			chan->backend.name, cpu,
 			v_read(config, &buf->records_count),
 			v_read(config, &buf->records_overrun));
+	}
+}
+#else
+static
+void lib_ring_buffer_print_records_count(struct channel *chan,
+					 struct lib_ring_buffer *buf,
+					 int cpu)
+{
+}
+#endif
+
+static
+void lib_ring_buffer_print_errors(struct channel *chan,
+				  struct lib_ring_buffer *buf, int cpu)
+{
+	const struct lib_ring_buffer_config *config = &chan->backend.config;
+	void *priv = chan->backend.priv;
 
+	lib_ring_buffer_print_records_count(chan, buf, cpu);
+	if (strcmp(chan->backend.name, "relay-metadata")) {
 		if (v_read(config, &buf->records_lost_full)
 		    || v_read(config, &buf->records_lost_wrap)
 		    || v_read(config, &buf->records_lost_big))
@@ -1596,14 +1627,26 @@ void lib_ring_buffer_switch_old_end(struct lib_ring_buffer *buf,
 	unsigned long oldidx = subbuf_index(offsets->old - 1, chan);
 	unsigned long commit_count, padding_size, data_size;
 	struct commit_counters_hot *cc_hot;
+	u64 *ts_end;
 
 	data_size = subbuf_offset(offsets->old - 1, chan) + 1;
 	padding_size = chan->backend.subbuf_size - data_size;
 	subbuffer_set_data_size(config, &buf->backend, oldidx, data_size);
 
+	ts_end = &buf->ts_end[oldidx];
 	/*
-	 * Order all writes to buffer before the commit count update that will
-	 * determine that the subbuffer is full.
+	 * This is the last space reservation in that sub-buffer before
+	 * it gets delivered. This provides exclusive access to write to
+	 * this sub-buffer's ts_end. There are also no concurrent
+	 * readers of that ts_end because delivery of that sub-buffer is
+	 * postponed until the commit counter is incremented for the
+	 * current space reservation.
+	 */
+	*ts_end = tsc;
+
+	/*
+	 * Order all writes to buffer and store to ts_end before the commit
+	 * count update that will determine that the subbuffer is full.
 	 */
 	if (config->ipi == RING_BUFFER_IPI_BARRIER) {
 		/*
@@ -1684,10 +1727,21 @@ void lib_ring_buffer_switch_new_end(struct lib_ring_buffer *buf,
 {
 	const struct lib_ring_buffer_config *config = &chan->backend.config;
 	unsigned long endidx, data_size;
+	u64 *ts_end;
 
 	endidx = subbuf_index(offsets->end - 1, chan);
 	data_size = subbuf_offset(offsets->end - 1, chan) + 1;
 	subbuffer_set_data_size(config, &buf->backend, endidx, data_size);
+	ts_end = &buf->ts_end[endidx];
+	/*
+	 * This is the last space reservation in that sub-buffer before
+	 * it gets delivered. This provides exclusive access to write to
+	 * this sub-buffer's ts_end. There are also no concurrent
+	 * readers of that ts_end because delivery of that sub-buffer is
+	 * postponed until the commit counter is incremented for the
+	 * current space reservation.
+	 */
+	*ts_end = tsc;
 }
 
 /*
@@ -2249,14 +2303,24 @@ void lib_ring_buffer_check_deliver_slow(const struct lib_ring_buffer_config *con
 	if (likely(v_cmpxchg(config, &buf->commit_cold[idx].cc_sb,
 				 old_commit_count, old_commit_count + 1)
 		   == old_commit_count)) {
+		u64 *ts_end;
+
 		/*
 		 * Start of exclusive subbuffer access. We are
 		 * guaranteed to be the last writer in this subbuffer
 		 * and any other writer trying to access this subbuffer
 		 * in this state is required to drop records.
+		 *
+		 * We can read the ts_end for the current sub-buffer
+		 * which has been saved by the very last space
+		 * reservation for the current sub-buffer.
+		 *
+		 * Order increment of commit counter before reading ts_end.
 		 */
+		smp_mb();
+		ts_end = &buf->ts_end[idx];
 		deliver_count_events(config, buf, idx);
-		config->cb.buffer_end(buf, tsc, idx,
+		config->cb.buffer_end(buf, *ts_end, idx,
 				      lib_ring_buffer_get_data_size(config,
 								buf,
 								idx));