linux/net
Eric Dumazet f8071cde78 tcp: enhance tcp_collapse_retrans() with skb_shift()
In commit 2331ccc5b3 ("tcp: enhance tcp collapsing"),
we made a first step allowing copying right skb to left skb head.

Since all skbs in socket write queue are headless (but possibly the very
first one), this strategy often does not work.

This patch extends tcp_collapse_retrans() to perform frag shifting,
thanks to skb_shift() helper.

This helper needs to not BUG on non headless skbs, as callers are ok
with that.

Tested:

Following packetdrill test now passes :

0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

   +0 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 8>
   +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8>
+.100 < . 1:1(0) ack 1 win 257
   +0 accept(3, ..., ...) = 4

   +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0
   +0 write(4, ..., 200) = 200
   +0 > P. 1:201(200) ack 1
+.001 write(4, ..., 200) = 200
   +0 > P. 201:401(200) ack 1
+.001 write(4, ..., 200) = 200
   +0 > P. 401:601(200) ack 1
+.001 write(4, ..., 200) = 200
   +0 > P. 601:801(200) ack 1
+.001 write(4, ..., 200) = 200
   +0 > P. 801:1001(200) ack 1
+.001 write(4, ..., 100) = 100
   +0 > P. 1001:1101(100) ack 1
+.001 write(4, ..., 100) = 100
   +0 > P. 1101:1201(100) ack 1
+.001 write(4, ..., 100) = 100
   +0 > P. 1201:1301(100) ack 1
+.001 write(4, ..., 100) = 100
   +0 > P. 1301:1401(100) ack 1

+.099 < . 1:1(0) ack 201 win 257
+.001 < . 1:1(0) ack 201 win 257 <nop,nop,sack 1001:1401>
   +0 > P. 201:1001(800) ack 1

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-24 15:40:42 -05:00
..
6lowpan 6lowpan: ndisc: no overreact if no short address is available 2016-09-19 20:19:34 +02:00
9p IB/core: add support to create a unsafe global rkey to ib_create_pd 2016-09-23 13:47:44 -04:00
802 net: use core MTU range checking in misc drivers 2016-10-20 14:51:10 -04:00
8021q netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
appletalk
atm net: remove MTU limits on a few ether_setup callers 2016-10-21 13:57:50 -04:00
ax25
batman-adv Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
bluetooth Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-30 12:42:58 -04:00
bridge bridge: mcast: add MLDv2 querier support 2016-11-21 13:16:58 -05:00
caif netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
can can: bcm: fix warning in bcm_connect/proc_register 2016-10-31 20:48:19 +01:00
ceph libceph: initialize last_linger_id with a large integer 2016-11-10 20:13:08 +01:00
core tcp: enhance tcp_collapse_retrans() with skb_shift() 2016-11-24 15:40:42 -05:00
dcb
dccp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-15 10:54:36 -05:00
decnet net: fix sleeping for sk_wait_event() 2016-11-14 13:17:21 -05:00
dns_resolver
dsa net: remove MTU limits on a few ether_setup callers 2016-10-21 13:57:50 -04:00
ethernet net: make default TX queue length a defined constant 2016-11-07 20:15:55 -05:00
hsr Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-30 12:42:58 -04:00
ieee802154 genetlink: mark families as __ro_after_init 2016-10-27 16:16:09 -04:00
ipv4 tcp: enhance tcp_collapse_retrans() with skb_shift() 2016-11-24 15:40:42 -05:00
ipv6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
ipx
irda genetlink: mark families as __ro_after_init 2016-10-27 16:16:09 -04:00
iucv Subject: [PATCH] af_iucv: drop skbs rejected by filter 2016-10-12 01:56:04 -04:00
kcm Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-10-07 15:36:58 -07:00
key netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
l2tp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
l3mdev
lapb
llc net: fix sleeping for sk_wait_event() 2016-11-14 13:17:21 -05:00
mac80211 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
mac802154 mac802154: use rate limited warnings for malformed frames 2016-09-19 20:19:34 +02:00
mpls lwt: Remove unused len field 2016-10-23 17:45:01 -04:00
ncsi net/ncsi: Improve HNCDSC AEN handler 2016-10-20 11:23:08 -04:00
netfilter netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
netlabel genetlink: mark families as __ro_after_init 2016-10-27 16:16:09 -04:00
netlink Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-15 10:54:36 -05:00
netrom
nfc genetlink: mark families as __ro_after_init 2016-10-27 16:16:09 -04:00
openvswitch netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
packet af_packet: Use virtio_net_hdr_from_skb() directly. 2016-11-19 10:37:03 -05:00
phonet netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
qrtr
rds netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
rfkill
rose
rxrpc udp: do fwd memory scheduling on dequeue 2016-11-07 13:24:41 -05:00
sched Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
sctp sctp: use new rhlist interface on sctp transport rhashtable 2016-11-16 23:22:17 -05:00
strparser strparser: Propagate correct error code in strp_recv() 2016-10-12 01:51:49 -04:00
sunrpc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
switchdev Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-30 12:42:58 -04:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
unix Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
vmw_vsock VSOCK: add loopback to virtio_transport 2016-11-24 11:53:15 -05:00
wimax genetlink: mark families as __ro_after_init 2016-10-27 16:16:09 -04:00
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
x25
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2016-10-28 13:26:27 -04:00
compat.c
Kconfig
Makefile
socket.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
sysctl_net.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2016-10-06 09:52:23 -07:00