diff options
| author | Jon Maloy <jon.maloy@ericsson.com> | 2017-11-30 18:47:25 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-01 23:21:25 +0300 |
| commit | 4c94cc2d3d57a2e843ab10887f67faa82c2337f9 (patch) | |
| tree | 5a45310f3e6802cd7bc958806ea770c23cab66d5 /net/tipc/bcast.c | |
| parent | 201c78e05c5adaffa163b022c9b3a4d30debe100 (diff) | |
| download | linux-4c94cc2d3d57a2e843ab10887f67faa82c2337f9.tar.xz | |
tipc: fall back to smaller MTU if allocation of local send skb fails
When sending node local messages the code is using an 'mtu' of 66060
bytes to avoid unnecessary fragmentation. During situations of low
memory tipc_msg_build() may sometimes fail to allocate such large
buffers, resulting in unnecessary send failures. This can easily be
remedied by falling back to a smaller MTU, and then reassemble the
buffer chain as if the message were arriving from a remote node.
At the same time, we change the initial MTU setting of the broadcast
link to a lower value, so that large messages always are fragmented
into smaller buffers even when we run in single node mode. Apart from
obtaining the same advantage as for the 'fallback' solution above, this
turns out to give a significant performance improvement. This can
probably be explained with the __pskb_copy() operation performed on the
buffer for each recipient during reception. We found the optimal value
for this, considering the most relevant skb pool, to be 3744 bytes.
Acked-by: Ying Xue <ying.xue@ericsson.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/bcast.c')
| -rw-r--r-- | net/tipc/bcast.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c index 329325bd553e..37892b3909af 100644 --- a/net/tipc/bcast.c +++ b/net/tipc/bcast.c @@ -1,7 +1,7 @@ /* * net/tipc/bcast.c: TIPC broadcast code * - * Copyright (c) 2004-2006, 2014-2016, Ericsson AB + * Copyright (c) 2004-2006, 2014-2017, Ericsson AB * Copyright (c) 2004, Intel Corporation. * Copyright (c) 2005, 2010-2011, Wind River Systems * All rights reserved. @@ -42,8 +42,8 @@ #include "link.h" #include "name_table.h" -#define BCLINK_WIN_DEFAULT 50 /* bcast link window size (default) */ -#define BCLINK_WIN_MIN 32 /* bcast minimum link window size */ +#define BCLINK_WIN_DEFAULT 50 /* bcast link window size (default) */ +#define BCLINK_WIN_MIN 32 /* bcast minimum link window size */ const char tipc_bclink_name[] = "broadcast-link"; @@ -74,6 +74,10 @@ static struct tipc_bc_base *tipc_bc_base(struct net *net) return tipc_net(net)->bcbase; } +/* tipc_bcast_get_mtu(): -get the MTU currently used by broadcast link + * Note: the MTU is decremented to give room for a tunnel header, in + * case the message needs to be sent as replicast + */ int tipc_bcast_get_mtu(struct net *net) { return tipc_link_mtu(tipc_bc_sndlink(net)) - INT_H_SIZE; @@ -515,7 +519,7 @@ int tipc_bcast_init(struct net *net) spin_lock_init(&tipc_net(net)->bclock); if (!tipc_link_bc_create(net, 0, 0, - U16_MAX, + FB_MTU, BCLINK_WIN_DEFAULT, 0, &bb->inputq, |