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alistair23-linux/include/net
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David S. Miller 62fa8a846d net: Implement read-only protection and COW'ing of metrics. 
Routing metrics are now copy-on-write.

Initially a route entry points it's metrics at a read-only location.
If a routing table entry exists, it will point there.  Else it will
point at the all zero metric place-holder called 'dst_default_metrics'.

The writeability state of the metrics is stored in the low bits of the
metrics pointer, we have two bits left to spare if we want to store
more states.

For the initial implementation, COW is implemented simply via kmalloc.
However future enhancements will change this to place the writable
metrics somewhere else, in order to increase sharing.  Very likely
this "somewhere else" will be the inetpeer cache.

Note also that this means that metrics updates may transiently fail
if we cannot COW the metrics successfully.

But even by itself, this patch should decrease memory usage and
increase cache locality especially for routing workloads.  In those
cases the read-only metric copies stay in place and never get written
to.

TCP workloads where metrics get updated, and those rare cases where
PMTU triggers occur, will take a very slight performance hit.  But
that hit will be alleviated when the long-term writable metrics
move to a more sharable location.

Since the metrics storage went from a u32 array of RTAX_MAX entries to
what is essentially a pointer, some retooling of the dst_entry layout
was necessary.

Most importantly, we need to preserve the alignment of the reference
count so that it doesn't share cache lines with the read-mostly state,
as per Eric Dumazet's alignment assertion checks.

The only non-trivial bit here is the move of the 'flags' member into
the writeable cacheline.  This is OK since we are always accessing the
flags around the same moment when we made a modification to the
reference count.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-26 20:51:05 -08:00
..
9p 9p: Add datasync to client side TFSYNC/RFSYNC for dotl 2010-10-28 09:08:49 -05:00
bluetooth Bluetooth: Fix race condition with conn->sec_level 2011-01-19 14:43:11 -02:00
caif include/net/caif/cfctrl.h: Remove unnecessary semicolons 2010-11-15 11:07:16 -08:00
irda net: return operator cleanup 2010-09-23 14:33:39 -07:00
iucv include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
netfilter netfilter: nf_conntrack: fix linker error with NF_CONNTRACK_TIMESTAMP=n 2011-01-20 20:46:52 +01:00
netns netfilter: nf_conntrack_tstamp: add flow-based timestamp extension 2011-01-19 16:00:07 +01:00
phonet phonet: some signedness bugs 2011-01-10 13:33:17 -08:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2011-01-19 20:25:45 -08:00
tc_act net/sched: add ACT_CSUM action to update packets checksums 2010-08-20 01:42:59 -07:00
act_api.h pkt_sched: gen_kill_estimator() rcu fixes 2010-06-11 18:37:08 -07:00
addrconf.h net: kill unused macros from head file 2010-12-02 13:27:33 -08:00
af_ieee802154.h
af_rxrpc.h
af_unix.h af_unix: limit recursion level 2010-11-29 09:45:15 -08:00
ah.h ipsec: update MAX_AH_AUTH_LEN to support sha512 2011-01-13 21:48:25 -08:00
arp.h arp: allow to invalidate specific ARP entries 2011-01-10 16:10:37 -08:00
atmclip.h
ax25.h include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ax88796.h
cfg80211.h cfg80211: add mesh join/leave callback docs 2011-01-10 15:40:52 -05:00
checksum.h
cipso_ipv4.h
cls_cgroup.h Merge commit 'v2.6.36-rc7' into core/rcu 2010-10-07 09:43:45 +02:00
compat.h net: fix compat_sys_recvmmsg parameter type 2009-12-11 15:07:56 -08:00
datalink.h
dcbevent.h net_dcb: add application notifiers 2010-12-31 10:47:46 -08:00
dcbnl.h dcbnl: adding DCBX feature flags get-set 2010-12-31 10:50:54 -08:00
dn.h net: avoid limits overflow 2010-11-10 12:12:00 -08:00
dn_dev.h decnet: RCU conversion and get rid of dev_base_lock 2010-11-08 13:50:08 -08:00
dn_fib.h decnet: Remove unused FIB metric macros. 2010-03-27 19:23:46 -07:00
dn_neigh.h
dn_nsp.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
dn_route.h ipv4: Make rt->fl.iif tests lest obscure. 2010-11-11 17:07:48 -08:00
dsa.h
dsfield.h
dst.h net: Implement read-only protection and COW'ing of metrics. 2011-01-26 20:51:05 -08:00
dst_ops.h net: Implement read-only protection and COW'ing of metrics. 2011-01-26 20:51:05 -08:00
esp.h
ethoc.h
fib_rules.h fib_rules: __rcu annotates ctarget 2010-10-27 11:37:32 -07:00
flow.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-12-26 22:37:05 -08:00
garp.h net/802: add __rcu annotations 2010-10-25 13:09:44 -07:00
gen_stats.h net: cleanup include/net 2009-11-04 05:06:25 -08:00
genetlink.h genetlink: introduce pre_doit/post_doit hooks 2010-10-05 13:35:30 -04:00
gre.h PPTP: PPP over IPv4 (Point-to-Point Tunneling Protocol) 2010-08-21 23:05:39 -07:00
icmp.h ipv4: raw: move struct raw_sock and raw_sk() to include/net/raw.h 2010-04-13 14:49:31 -07:00
ieee80211_radiotap.h wireless: update radiotap parser 2010-02-08 16:50:53 -05:00
ieee802154.h
ieee802154_netdev.h ieee802154: add an mlme_ops call to retrieve PHY object 2009-11-06 14:32:18 +03:00
if_inet6.h ipv6: mcast: RCU conversion 2010-11-24 11:16:42 -08:00
inet6_connection_sock.h ipv6: Create inet6_csk_route_req(). 2010-12-02 10:59:22 -08:00
inet6_hashtables.h tcp: Fix a connect() race with timewait sockets 2009-12-08 20:17:51 -08:00
inet_common.h inet, inet6: make tcp_sendmsg() and tcp_sendpage() through inet_sendmsg() and inet_sendpage() 2010-07-12 20:21:46 -07:00
inet_connection_sock.h net: kill unused macros 2010-12-19 21:59:35 -08:00
inet_ecn.h net: return operator cleanup 2010-09-23 14:33:39 -07:00
inet_frag.h fragment: add fast path for in-order fragments 2010-06-30 13:44:29 -07:00
inet_hashtables.h tproxy: fix hash locking issue when using port redirection in __inet_inherit_port() 2010-10-21 13:06:43 +02:00
inet_sock.h net: optimize INET input path further 2010-12-09 20:05:58 -08:00
inet_timewait_sock.h net: optimize INET input path further 2010-12-09 20:05:58 -08:00
inetpeer.h inetpeer: Fix incorrect comment about inetpeer struct size. 2010-12-01 17:29:08 -08:00
ip.h ipv4: Don't pre-seed hoplimit metric. 2010-12-12 22:08:17 -08:00
ip6_checksum.h
ip6_fib.h ipv6: Add infrastructure to bind inet_peer objects to routes. 2010-11-30 12:27:11 -08:00
ip6_route.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-12-20 13:24:14 -08:00
ip6_tunnel.h tunnels: add _rcu annotations 2010-10-25 13:09:45 -07:00
ip_fib.h netfilter: fix Kconfig dependencies 2011-01-14 13:36:42 +01:00
ip_vs.h IPVS: netns, trash handling 2011-01-13 10:30:28 +09:00
ipcomp.h percpu: add __percpu sparse annotations to net 2010-02-16 23:05:38 -08:00
ipconfig.h
ipip.h tunnels: add __rcu annotations 2010-10-27 11:37:32 -07:00
ipv6.h net: return operator cleanup 2010-09-23 14:33:39 -07:00
ipx.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
iw_handler.h include/net/iw_handler.h: Use SIOCIWFIRST not SIOCSIWCOMMIT in comment 2010-03-31 14:49:12 -04:00
lapb.h
lib80211.h lib80211: remove unused host_build_iv option 2010-07-26 15:09:04 -04:00
llc.h llc: convert llc_sap_list to RCU 2009-12-26 20:46:28 -08:00
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h llc: use a device based hash table to speed up multicast delivery 2009-12-26 20:43:57 -08:00
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
mac80211.h mac80211: add missing docs for off-chan TX flag 2011-01-10 15:40:52 -05:00
mip6.h net: use __packed annotation 2010-06-03 03:21:52 -07:00
mld.h ipv6 mcast: Introduce include/net/mld.h for MLD definitions. 2010-04-23 13:35:55 +09:00
ndisc.h net: kill unused macros from head file 2010-12-02 13:27:33 -08:00
neighbour.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-11-19 13:13:47 -08:00
net_namespace.h IPVS: netns, add basic init per netns. 2011-01-13 10:30:26 +09:00
netdma.h
netevent.h
netlabel.h include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
netlink.h netlink: let nlmsg and nla functions take pointer-to-const args 2010-11-16 09:52:32 -08:00
netrom.h include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
nexthop.h
nl802154.h ieee802154: add support for channel pages from IEEE 802.15.4-2006 2009-08-19 23:08:22 +04:00
p8022.h
pkt_cls.h net: Fix range checks in tcf_valid_offset(). 2010-12-21 12:43:16 -08:00
pkt_sched.h net: Define accessors to manipulate QDISC_STATE_RUNNING 2010-06-02 03:23:51 -07:00
protocol.h net: change netdev->features to u32 2011-01-24 15:32:47 -08:00
psnap.h
raw.h include/net/raw.h: Convert raw_seq_private macro to inline 2010-09-08 13:42:22 -07:00
rawv6.h
red.h sched: remove unused backlog in RED stats 2011-01-12 19:00:39 -08:00
regulatory.h cfg80211: Fix regulatory bug with multiple cards and delays 2010-11-22 15:48:51 -05:00
request_sock.h tcp: account SYN-ACK timeouts & retransmissions 2010-01-17 19:09:39 -08:00
rose.h
route.h net: Implement read-only protection and COW'ing of metrics. 2011-01-26 20:51:05 -08:00
rtnetlink.h rtnl: make link af-specific updates atomic 2010-11-27 22:56:08 -08:00
sch_generic.h Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2011-01-24 14:09:35 -08:00
scm.h scm: lower SCM_MAX_FD 2010-11-24 11:16:43 -08:00
slhc_vj.h
snmp.h net: kill unused macros from head file 2010-12-02 13:27:33 -08:00
sock.h net: filter: dont block softirqs in sk_run_filter() 2011-01-18 21:33:05 -08:00
stp.h
tcp.h net: change netdev->features to u32 2011-01-24 15:32:47 -08:00
tcp_states.h
timewait_sock.h timewait_sock: Create and use getpeer op. 2010-12-01 18:09:13 -08:00
transp_v6.h IPv6: Add dontfrag argument to relevant functions 2010-04-23 23:35:28 -07:00
udp.h net: change netdev->features to u32 2011-01-24 15:32:47 -08:00
udplite.h
wext.h wext: refactor 2009-10-07 16:39:43 -04:00
wimax.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-12-09 19:43:33 -08:00
wpan-phy.h ieee802154: add support for creation/removal of logic interfaces 2009-11-06 14:32:24 +03:00
x25.h X25 remove bkl in subscription ioctls 2010-11-28 11:12:20 -08:00
x25device.h X25: Add if_x25.h and x25 to device identifiers 2010-04-22 16:12:36 -07:00
xfrm.h xfrm: Add Traffic Flow Confidentiality padding XFRM attribute 2010-12-10 14:43:58 -08:00