tipc: enable broadcast retrans via unicast

In some environment, broadcast traffic is suppressed at high rate (i.e.
a kind of bandwidth limit setting). When it is applied, TIPC broadcast
can still run successfully. However, when it comes to a high load, some
packets will be dropped first and TIPC tries to retransmit them but the
packet retransmission is intentionally broadcast too, so making things
worse and not helpful at all.

This commit enables the broadcast retransmission via unicast which only
retransmits packets to the specific peer that has really reported a gap
i.e. not broadcasting to all nodes in the cluster, so will prevent from
being suppressed, and also reduce some overheads on the other peers due
to duplicates, finally improve the overall TIPC broadcast performance.

Note: the functionality can be turned on/off via the sysctl file:

echo 1 > /proc/sys/net/tipc/bc_retruni
echo 0 > /proc/sys/net/tipc/bc_retruni

Default is '0', i.e. the broadcast retransmission still works as usual.

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 3ce690a96ee9d6d620f34783a253d94403cdcf4e..50a16f8bebd96db5e5a894fe2fd376a7bb3a68af 100644 (file)
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -46,6 +46,7 @@
 #define BCLINK_WIN_MIN      32 /* bcast minimum link window size */
 
 const char tipc_bclink_name[] = "broadcast-link";
+unsigned long sysctl_tipc_bc_retruni __read_mostly;
 
 /**
  * struct tipc_bc_base - base structure for keeping broadcast send state
@@ -474,7 +475,7 @@ void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l,
        __skb_queue_head_init(&xmitq);
 
        tipc_bcast_lock(net);
-       tipc_link_bc_ack_rcv(l, acked, 0, NULL, &xmitq);
+       tipc_link_bc_ack_rcv(l, acked, 0, NULL, &xmitq, NULL);
        tipc_bcast_unlock(net);
 
        tipc_bcbase_xmit(net, &xmitq);
@@ -489,7 +490,8 @@ void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l,
  * RCU is locked, no other locks set
  */
 int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
-                       struct tipc_msg *hdr)
+                       struct tipc_msg *hdr,
+                       struct sk_buff_head *retrq)
 {
        struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
        struct tipc_gap_ack_blks *ga;
@@ -503,8 +505,11 @@ int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
                tipc_link_bc_init_rcv(l, hdr);
        } else if (!msg_bc_ack_invalid(hdr)) {
                tipc_get_gap_ack_blks(&ga, l, hdr, false);
+               if (!sysctl_tipc_bc_retruni)
+                       retrq = &xmitq;
                rc = tipc_link_bc_ack_rcv(l, msg_bcast_ack(hdr),
-                                         msg_bc_gap(hdr), ga, &xmitq);
+                                         msg_bc_gap(hdr), ga, &xmitq,
+                                         retrq);
                rc |= tipc_link_bc_sync_rcv(l, hdr, &xmitq);
        }
        tipc_bcast_unlock(net);

diff --git a/net/tipc/bcast.h b/net/tipc/bcast.h
index 9e847d9617d3d5a5b240f931eaeb14e0502f883a..97d3cf9d3e4d000555ab3d897915032eb5abbc0b 100644 (file)
--- a/net/tipc/bcast.h
+++ b/net/tipc/bcast.h
@@ -45,6 +45,7 @@ struct tipc_nl_msg;
 struct tipc_nlist;
 struct tipc_nitem;
 extern const char tipc_bclink_name[];
+extern unsigned long sysctl_tipc_bc_retruni;
 
 #define TIPC_METHOD_EXPIRE msecs_to_jiffies(5000)
 
@@ -93,7 +94,8 @@ int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb);
 void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l,
                        struct tipc_msg *hdr);
 int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
-                       struct tipc_msg *hdr);
+                       struct tipc_msg *hdr,
+                       struct sk_buff_head *retrq);
 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg);
 int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[]);
 int tipc_bclink_reset_stats(struct net *net);

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 288c5670cfa5f3f1df34dbccb1ebd5e682385b46..af352391e2ab995446dc315f99db87194d2aacca 100644 (file)
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -375,7 +375,7 @@ void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
        snd_l->ackers--;
        rcv_l->bc_peer_is_up = true;
        rcv_l->state = LINK_ESTABLISHED;
-       tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq);
+       tipc_link_bc_ack_rcv(rcv_l, ack, 0, NULL, xmitq, NULL);
        trace_tipc_link_reset(rcv_l, TIPC_DUMP_ALL, "bclink removed!");
        tipc_link_reset(rcv_l);
        rcv_l->state = LINK_RESET;
@@ -2400,7 +2400,8 @@ int tipc_link_bc_sync_rcv(struct tipc_link *l, struct tipc_msg *hdr,
 
 int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
                         struct tipc_gap_ack_blks *ga,
-                        struct sk_buff_head *xmitq)
+                        struct sk_buff_head *xmitq,
+                        struct sk_buff_head *retrq)
 {
        struct tipc_link *l = r->bc_sndlink;
        bool unused = false;
@@ -2413,7 +2414,7 @@ int tipc_link_bc_ack_rcv(struct tipc_link *r, u16 acked, u16 gap,
                return 0;
 
        trace_tipc_link_bc_ack(r, acked, gap, &l->transmq);
-       tipc_link_advance_transmq(l, r, acked, gap, ga, xmitq, &unused, &rc);
+       tipc_link_advance_transmq(l, r, acked, gap, ga, retrq, &unused, &rc);
 
        tipc_link_advance_backlog(l, xmitq);
        if (unlikely(!skb_queue_empty(&l->wakeupq)))
@@ -2447,7 +2448,8 @@ int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
                return 0;
 
        if (dnode == tipc_own_addr(l->net)) {
-               rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq);
+               rc = tipc_link_bc_ack_rcv(l, acked, to - acked, NULL, xmitq,
+                                         xmitq);
                l->stats.recv_nacks++;
                return rc;
        }

diff --git a/net/tipc/link.h b/net/tipc/link.h
index 0a0fa7350722a60e1aed169f89cf3ac00a6f54df..4d0768cf91d5eb9c7937d2c248099e4f7655a97b 100644 (file)
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -147,7 +147,8 @@ u16 tipc_get_gap_ack_blks(struct tipc_gap_ack_blks **ga, struct tipc_link *l,
                          struct tipc_msg *hdr, bool uc);
 int tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked, u16 gap,
                         struct tipc_gap_ack_blks *ga,
-                        struct sk_buff_head *xmitq);
+                        struct sk_buff_head *xmitq,
+                        struct sk_buff_head *retrq);
 void tipc_link_build_bc_sync_msg(struct tipc_link *l,
                                 struct sk_buff_head *xmitq);
 void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr);

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 6a49b3eeaae91f043d9e7e15c28a492fb493e2c2..548207fdec15e3a7fa6ab205129702785e1c51f2 100644 (file)
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -1772,7 +1772,7 @@ static void tipc_node_bc_sync_rcv(struct tipc_node *n, struct tipc_msg *hdr,
        struct tipc_link *ucl;
        int rc;
 
-       rc = tipc_bcast_sync_rcv(n->net, n->bc_entry.link, hdr);
+       rc = tipc_bcast_sync_rcv(n->net, n->bc_entry.link, hdr, xmitq);
 
        if (rc & TIPC_LINK_DOWN_EVT) {
                tipc_node_reset_links(n);

diff --git a/net/tipc/sysctl.c b/net/tipc/sysctl.c
index 58ab3d6dcdce48a8a0c62fa57e9b0a688f9f2a9c..97a6264a29931b72f1edcceea768a6e2bf7abbb8 100644 (file)
--- a/net/tipc/sysctl.c
+++ b/net/tipc/sysctl.c
@@ -36,7 +36,7 @@
 #include "core.h"
 #include "trace.h"
 #include "crypto.h"
-
+#include "bcast.h"
 #include <linux/sysctl.h>
 
 static struct ctl_table_header *tipc_ctl_hdr;
@@ -75,6 +75,13 @@ static struct ctl_table tipc_table[] = {
                .extra1         = SYSCTL_ONE,
        },
 #endif
+       {
+               .procname       = "bc_retruni",
+               .data           = &sysctl_tipc_bc_retruni,
+               .maxlen         = sizeof(sysctl_tipc_bc_retruni),
+               .mode           = 0644,
+               .proc_handler   = proc_doulongvec_minmax,
+       },
        {}
 };