MFC [Hyper-V]: r294553, r294700

r294553

hyperv/vmbus: Lookup channel through id table

Vmbus event handler will need to find the channel by its relative
id, when software interrupt for event happens.  The original lookup
searches the channel list, which is not very efficient.  We now
create a table indexed by the channel relative id to speed up
the channel lookup.

Submitted by:           Hongjiang Zhang <honzhan microsoft com>
Reviewed by:            delphij, adrain, sephe, Dexuan Cui <decui microsoft com>
Approved by:            adrian (mentor)
Sponsored by:           Microsoft OSTC
Differential Revision:  https://reviews.freebsd.org/D4802

-------------

r294700

hyperv/hn: Partly rework transmission path

- Avoid unnecessary malloc/free on transmission path.
- busdma(9)-fy transmission path.
- Properly handle IFF_DRV_OACTIVE.  This should fix the network
  stalls reported by many.
- Properly setup TSO parameters.
- Properly handle bpf(4) tapping.  This 5 times the performance
  during TCP sending test, when there is one bpf(4) attached.
- Allow size of chimney sending be tuned on a running system.
  Default value still needs more test to determine.

Reviewed by:            adrian, delphij
Approved by:            adrian (mentor)
Sponsored by:           Microsoft OSTC
Differential Revision:  https://reviews.freebsd.org/D4972

Approved by:	re (marius)
Sponsored by:	Microsoft OSTC

3 files changed, 32 insertions, 38 deletions

diff --git a/sys/dev/hyperv/vmbus/hv_channel_mgmt.c b/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
index c7f3538..4ccb647 100644
--- a/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
+++ b/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
@@ -274,14 +274,16 @@ vmbus_channel_process_offer(hv_vmbus_channel *new_channel)
 	boolean_t		f_new;
 	hv_vmbus_channel*	channel;
 	int			ret;
+	uint32_t                relid;
 
 	f_new = TRUE;
 	channel = NULL;
-
+	relid = new_channel->offer_msg.child_rel_id;
 	/*
 	 * Make sure this is a new offer
 	 */
 	mtx_lock(&hv_vmbus_g_connection.channel_lock);
+	hv_vmbus_g_connection.channels[relid] = new_channel;
 
 	TAILQ_FOREACH(channel, &hv_vmbus_g_connection.channel_anchor,
 	    list_entry)
@@ -325,16 +327,18 @@ vmbus_channel_process_offer(hv_vmbus_channel *new_channel)
 			mtx_unlock(&channel->sc_lock);
 
 			/* Insert new channel into channel_anchor. */
-			printf("Storvsc get multi-channel offer, rel=%u.\n",
-			    new_channel->offer_msg.child_rel_id);	
+			printf("VMBUS get multi-channel offer, rel=%u,sub=%u\n",
+			    new_channel->offer_msg.child_rel_id,
+			    new_channel->offer_msg.offer.sub_channel_index);	
 			mtx_lock(&hv_vmbus_g_connection.channel_lock);
 			TAILQ_INSERT_TAIL(&hv_vmbus_g_connection.channel_anchor,
 			    new_channel, list_entry);				
 			mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 
 			if(bootverbose)
-				printf("VMBUS: new multi-channel offer <%p>.\n",
-				    new_channel);
+				printf("VMBUS: new multi-channel offer <%p>, "
+				    "its primary channel is <%p>.\n",
+				    new_channel, new_channel->primary_channel);
 
 			/*XXX add it to percpu_list */
 
@@ -524,11 +528,14 @@ vmbus_channel_on_offer_rescind(hv_vmbus_channel_msg_header* hdr)
 
 	rescind = (hv_vmbus_channel_rescind_offer*) hdr;
 
-	channel = hv_vmbus_get_channel_from_rel_id(rescind->child_rel_id);
+	channel = hv_vmbus_g_connection.channels[rescind->child_rel_id];
 	if (channel == NULL) 
 	    return;
 
 	hv_vmbus_child_device_unregister(channel->device);
+	mtx_lock(&hv_vmbus_g_connection.channel_lock);
+	hv_vmbus_g_connection.channels[rescind->child_rel_id] = NULL;
+	mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 }
 
 /**
@@ -782,6 +789,8 @@ hv_vmbus_release_unattached_channels(void)
 	    hv_vmbus_child_device_unregister(channel->device);
 	    hv_vmbus_free_vmbus_channel(channel);
 	}
+	bzero(hv_vmbus_g_connection.channels, 
+		sizeof(hv_vmbus_channel*) * HV_CHANNEL_MAX_COUNT);
 	mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 }
 
diff --git a/sys/dev/hyperv/vmbus/hv_connection.c b/sys/dev/hyperv/vmbus/hv_connection.c
index 7496288..a9e3561 100644
--- a/sys/dev/hyperv/vmbus/hv_connection.c
+++ b/sys/dev/hyperv/vmbus/hv_connection.c
@@ -232,6 +232,9 @@ hv_vmbus_connect(void) {
 	    goto cleanup;
 	}
 
+	hv_vmbus_g_connection.channels = malloc(sizeof(hv_vmbus_channel*) *
+		HV_CHANNEL_MAX_COUNT,
+		M_DEVBUF, M_WAITOK | M_ZERO);
 	/*
 	 * Find the highest vmbus version number we can support.
 	 */
@@ -295,6 +298,7 @@ hv_vmbus_connect(void) {
 		free(msg_info, M_DEVBUF);
 	}
 
+	free(hv_vmbus_g_connection.channels, M_DEVBUF);
 	return (ret);
 }
 
@@ -325,6 +329,7 @@ hv_vmbus_disconnect(void) {
 	hv_work_queue_close(hv_vmbus_g_connection.work_queue);
 	sema_destroy(&hv_vmbus_g_connection.control_sema);
 
+	free(hv_vmbus_g_connection.channels, M_DEVBUF);
 	hv_vmbus_g_connection.connect_state = HV_DISCONNECTED;
 
 	free(msg, M_DEVBUF);
@@ -333,35 +338,6 @@ hv_vmbus_disconnect(void) {
 }
 
 /**
- * Get the channel object given its child relative id (ie channel id)
- */
-hv_vmbus_channel*
-hv_vmbus_get_channel_from_rel_id(uint32_t rel_id) {
-
-	hv_vmbus_channel* channel;
-	hv_vmbus_channel* foundChannel = NULL;
-
-	/*
-	 * TODO:
-	 * Consider optimization where relids are stored in a fixed size array
-	 *  and channels are accessed without the need to take this lock or search
-	 *  the list.
-	 */
-	mtx_lock(&hv_vmbus_g_connection.channel_lock);
-	TAILQ_FOREACH(channel,
-		&hv_vmbus_g_connection.channel_anchor, list_entry) {
-
-	    if (channel->offer_msg.child_rel_id == rel_id) {
-		foundChannel = channel;
-		break;
-	    }
-	}
-	mtx_unlock(&hv_vmbus_g_connection.channel_lock);
-
-	return (foundChannel);
-}
-
-/**
  * Process a channel event notification
  */
 static void
@@ -377,7 +353,7 @@ VmbusProcessChannelEvent(uint32_t relid)
 	 * the channel callback to process the event
 	 */
 
-	channel = hv_vmbus_get_channel_from_rel_id(relid);
+	channel = hv_vmbus_g_connection.channels[relid];
 
 	if (channel == NULL) {
 		return;
@@ -473,7 +449,7 @@ hv_vmbus_on_events(void *arg)
 	if (recv_interrupt_page != NULL) {
 	    for (dword = 0; dword < maxdword; dword++) {
 		if (recv_interrupt_page[dword]) {
-		    for (bit = 0; bit < 32; bit++) {
+		    for (bit = 0; bit < HV_CHANNEL_DWORD_LEN; bit++) {
 			if (synch_test_and_clear_bit(bit,
 			    (uint32_t *) &recv_interrupt_page[dword])) {
 			    rel_id = (dword << 5) + bit;
diff --git a/sys/dev/hyperv/vmbus/hv_vmbus_priv.h b/sys/dev/hyperv/vmbus/hv_vmbus_priv.h
index 74fe824..13a35c4 100644
--- a/sys/dev/hyperv/vmbus/hv_vmbus_priv.h
+++ b/sys/dev/hyperv/vmbus/hv_vmbus_priv.h
@@ -58,6 +58,12 @@ typedef uint16_t hv_vmbus_status;
 #define HV_EVENT_FLAGS_BYTE_COUNT   (256)
 #define HV_EVENT_FLAGS_DWORD_COUNT  (256 / sizeof(uint32_t))
 
+/**
+ * max channel count <== event_flags_dword_count * bit_of_dword
+ */
+#define HV_CHANNEL_DWORD_LEN        (32)
+#define HV_CHANNEL_MAX_COUNT        \
+	((HV_EVENT_FLAGS_DWORD_COUNT) * HV_CHANNEL_DWORD_LEN)
 /*
  * MessageId: HV_STATUS_INSUFFICIENT_BUFFERS
  * MessageText:
@@ -355,6 +361,10 @@ typedef struct {
 	TAILQ_HEAD(, hv_vmbus_channel)		channel_anchor;
 	struct mtx				channel_lock;
 
+	/**
+	 * channel table for fast lookup through id.
+	 */
+	hv_vmbus_channel                        **channels;
 	hv_vmbus_handle				work_queue;
 	struct sema				control_sema;
 } hv_vmbus_connection;
@@ -699,7 +709,6 @@ int			hv_vmbus_child_device_register(
 					struct hv_device *child_dev);
 int			hv_vmbus_child_device_unregister(
 					struct hv_device *child_dev);
-hv_vmbus_channel*	hv_vmbus_get_channel_from_rel_id(uint32_t rel_id);
 
 /**
  * Connection interfaces