[tipc-discussion] [PATCH RFC] tipc: improve bundle algorithm

[Tuong L. <tuo...@de...>]

Signed-off-by: Tuong Lien <tuo...@de...>
---
 net/tipc/link.c | 29 ++++++++++++++++++-----------
 net/tipc/msg.c  |  4 ++--
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 6cc75ffd9e2c..22ba0c8af3a8 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -160,6 +160,7 @@ struct tipc_link {
 	struct {
 		u16 len;
 		u16 limit;
+		struct sk_buff *tskb;
 	} backlog[5];
 	u16 snd_nxt;
 	u16 window;
@@ -880,6 +881,7 @@ static void link_prepare_wakeup(struct tipc_link *l)
 void tipc_link_reset(struct tipc_link *l)
 {
 	struct sk_buff_head list;
+	u32 imp;
 
 	__skb_queue_head_init(&list);
 
@@ -901,11 +903,10 @@ void tipc_link_reset(struct tipc_link *l)
 	__skb_queue_purge(&l->deferdq);
 	__skb_queue_purge(&l->backlogq);
 	__skb_queue_purge(&l->failover_deferdq);
-	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
-	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
-	l->backlog[TIPC_HIGH_IMPORTANCE].len = 0;
-	l->backlog[TIPC_CRITICAL_IMPORTANCE].len = 0;
-	l->backlog[TIPC_SYSTEM_IMPORTANCE].len = 0;
+	for (imp = 0; imp <= TIPC_SYSTEM_IMPORTANCE; imp++) {
+		l->backlog[imp].len = 0;
+		l->backlog[imp].tskb = NULL;
+	}
 	kfree_skb(l->reasm_buf);
 	kfree_skb(l->reasm_tnlmsg);
 	kfree_skb(l->failover_reasm_skb);
@@ -947,7 +948,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
 	struct sk_buff_head *transmq = &l->transmq;
 	struct sk_buff_head *backlogq = &l->backlogq;
-	struct sk_buff *skb, *_skb, *bskb;
+	struct sk_buff *skb, *_skb, **tskb;
 	int pkt_cnt = skb_queue_len(list);
 	int rc = 0;
 
@@ -999,19 +1000,21 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
 			seqno++;
 			continue;
 		}
-		if (tipc_msg_bundle(skb_peek_tail(backlogq), hdr, mtu)) {
+		tskb = &l->backlog[imp].tskb;
+		if (tipc_msg_bundle(*tskb, hdr, mtu)) {
 			kfree_skb(__skb_dequeue(list));
 			l->stats.sent_bundled++;
 			continue;
 		}
-		if (tipc_msg_make_bundle(&bskb, hdr, mtu, l->addr)) {
+		if (tipc_msg_make_bundle(tskb, hdr, mtu, l->addr)) {
 			kfree_skb(__skb_dequeue(list));
-			__skb_queue_tail(backlogq, bskb);
-			l->backlog[msg_importance(buf_msg(bskb))].len++;
+			__skb_queue_tail(backlogq, *tskb);
+			l->backlog[imp].len++;
 			l->stats.sent_bundled++;
 			l->stats.sent_bundles++;
 			continue;
 		}
+		l->backlog[imp].tskb = NULL;
 		l->backlog[imp].len += skb_queue_len(list);
 		skb_queue_splice_tail_init(list, backlogq);
 	}
@@ -1027,6 +1030,7 @@ static void tipc_link_advance_backlog(struct tipc_link *l,
 	u16 seqno = l->snd_nxt;
 	u16 ack = l->rcv_nxt - 1;
 	u16 bc_ack = l->bc_rcvlink->rcv_nxt - 1;
+	u32 imp;
 
 	while (skb_queue_len(&l->transmq) < l->window) {
 		skb = skb_peek(&l->backlogq);
@@ -1037,7 +1041,10 @@ static void tipc_link_advance_backlog(struct tipc_link *l,
 			break;
 		__skb_dequeue(&l->backlogq);
 		hdr = buf_msg(skb);
-		l->backlog[msg_importance(hdr)].len--;
+		imp = msg_importance(hdr);
+		l->backlog[imp].len--;
+		if (unlikely(skb == l->backlog[imp].tskb))
+			l->backlog[imp].tskb = NULL;
 		__skb_queue_tail(&l->transmq, skb);
 		/* next retransmit attempt */
 		if (link_is_bc_sndlink(l))
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index e6d49cdc61b4..25c884cc8b88 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -518,7 +518,7 @@ bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
  * @dnode: destination node for message. (Not always present in header)
  * Returns true if success, otherwise false
  */
-bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
+bool tipc_msg_make_bundle(struct sk_buff **skb, struct tipc_msg *msg,
 			  u32 mtu, u32 dnode)
 {
 	struct sk_buff *_skb;
@@ -544,7 +544,7 @@ bool tipc_msg_make_bundle(struct sk_buff **skb,  struct tipc_msg *msg,
 	tipc_msg_init(msg_prevnode(msg), bmsg, MSG_BUNDLER, 0,
 		      INT_H_SIZE, dnode);
 	if (msg_isdata(msg))
-		msg_set_importance(bmsg, TIPC_CRITICAL_IMPORTANCE);
+		msg_set_importance(bmsg, msg_importance(msg));
 	else
 		msg_set_importance(bmsg, TIPC_SYSTEM_IMPORTANCE);
 	msg_set_seqno(bmsg, msg_seqno(msg));
-- 
2.13.7