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a297569fe0
linux/net
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Eric Dumazet a297569fe0 net/udp: do not touch skb->peeked unless really needed 
In UDP recvmsg() path we currently access 3 cache lines from an skb
while holding receive queue lock, plus another one if packet is
dequeued, since we need to change skb->next->prev

1st cache line (contains ->next/prev pointers, offsets 0x00 and 0x08)
2nd cache line (skb->len & skb->peeked, offsets 0x80 and 0x8e)
3rd cache line (skb->truesize/users, offsets 0xe0 and 0xe4)

skb->peeked is only needed to make sure 0-length packets are properly
handled while MSG_PEEK is operated.

I had first the intent to remove skb->peeked but the "MSG_PEEK at
non-zero offset" support added by Sam Kumar makes this not possible.

This patch avoids one cache line miss during the locked section, when
skb->len and skb->peeked do not have to be read.

It also avoids the skb_set_peeked() cost for non empty UDP datagrams.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-06 10:41:49 -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 appletalk: use IS_ENABLED() instead of checking for built-in or module 2016-09-10 21:19:10 -07:00
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 2016-11-26 23:42:21 -05:00
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 support for CAN FD frames 2016-11-23 15:22:18 +01:00
ceph libceph: initialize last_linger_id with a large integer 2016-11-10 20:13:08 +01:00
core net/udp: do not touch skb->peeked unless really needed 2016-12-06 10:41:49 -05:00
dcb
dccp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-03 12:29:53 -05:00
decnet net: fix sleeping for sk_wait_event() 2016-11-14 13:17:21 -05:00
dns_resolver
dsa Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-03 12:29:53 -05:00
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 ieee802154: check device type 2016-11-30 12:33:07 +01:00
ipv4 tcp: tsq: move tsq_flags close to sk_wmem_alloc 2016-12-05 13:32:24 -05:00
ipv6 ipv6: Allow IPv4-mapped address as next-hop 2016-12-05 14:52:05 -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 2016-12-03 12:29:53 -05:00
l3mdev net: ipv6: Remove l3mdev_get_saddr6 2016-09-10 23:12:53 -07:00
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 net_sched: gen_estimator: complete rewrite of rate estimators 2016-12-05 15:21:59 -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 2016-12-03 12:29:53 -05:00
netrom
nfc genetlink: mark families as __ro_after_init 2016-10-27 16:16:09 -04:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-03 12:29:53 -05:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-03 12:29:53 -05:00
phonet netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
qrtr
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-03 12:29:53 -05:00
rfkill
rose
rxrpc udp: do fwd memory scheduling on dequeue 2016-11-07 13:24:41 -05:00
sched bpf: add prog_digest and expose it via fdinfo/netlink 2016-12-05 15:33:11 -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 2016-12-03 12:29:53 -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 wireless-drivers-next patches for 4.10 2016-11-27 20:26:59 -05:00
x25 net: x25: remove null checks on arrays calling_ae and called_ae 2016-09-09 18:13:30 -07:00
xfrm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-03 12:29:53 -05:00
compat.c
Kconfig bpf: BPF for lightweight tunnel infrastructure 2016-12-02 10:51:49 -05:00
Makefile
socket.c tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING 2016-11-30 10:04:25 -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