Eric Dumazet 27b75c95f1 net: avoid RCU for NOCACHE dst ...

There is no point using RCU for dst we allocate for a very short time
(used once).

Change dst_release() to take DST_NOCACHE into account, but also change
skb_dst_set_noref() to force a refcount increment for such dst.

This is a _huge_ gain, because we dont waste memory to store xx thousand
of dsts. Instead of queueing them to RCU, we can free them instantly.

CPU caches can stay hot, re-using same memory blocks to hold temporary
dsts.

Note : remove unneeded smp_mb__before_atomic_dec(); in dst_release(),
since atomic_dec_return() implies a full memory barrier.

Stress test, 160.000.000 udp frames sent, IP route cache disabled
(DDOS).

Before:

real    0m38.091s
user    0m13.189s
sys     7m53.018s

After:

real	0m29.946s
user	0m12.157s
sys	7m40.605s

For reference, if IP route cache was enabled :

real	0m32.030s
user	0m10.521s
sys	8m15.243s

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2010-10-20 03:02:23 -07:00

..

datagram.c

net: poll() optimizations

2010-09-06 18:48:45 -07:00

dev_addr_lists.c

net: include linux/proc_fs.h in dev_addr_lists.c

2010-04-07 16:46:36 -07:00

dev.c

net: allocate tx queues in register_netdevice

2010-10-20 02:27:59 -07:00

drop_monitor.c

drop_monitor: use genl_register_family_with_ops()

2010-07-26 20:59:42 -07:00

dst.c

net: avoid RCU for NOCACHE dst

2010-10-20 03:02:23 -07:00

ethtool.c

Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

2010-10-11 12:30:34 -07:00

fib_rules.c

fib: remove a useless synchronize_rcu() call

2010-10-16 11:13:22 -07:00

filter.c

net: sk_{detach|attach}_filter() rcu fixes

2010-09-27 21:30:44 -07:00

flow.c

net: return operator cleanup

2010-09-23 14:33:39 -07:00

gen_estimator.c

pkt_sched: remov unnecessary bh_disable

2010-09-10 12:47:59 -07:00

gen_stats.c

net/core: EXPORT_SYMBOL cleanups

2010-07-12 12:57:55 -07:00

iovec.c

Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

2010-10-04 11:56:38 -07:00

kmap_skb.h

[PATCH] severing skbuff.h -> highmem.h

2006-12-04 02:00:29 -05:00

link_watch.c

net/core: EXPORT_SYMBOL cleanups

2010-07-12 12:57:55 -07:00

Makefile

net: support time stamping in phy devices.

2010-07-18 19:15:26 -07:00

neighbour.c

neigh: Protect neigh->ha[] with a seqlock

2010-10-11 12:54:04 -07:00

net_namespace.c

net: disallow to use net_assign_generic externally

2010-04-27 15:49:02 -07:00

net-sysfs.c

net: Fix rxq ref counting

2010-10-08 14:34:32 -07:00

net-sysfs.h

net: Allow changing number of RX queues after device allocation

2010-09-27 22:09:49 -07:00

net-traces.c

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

netevent.c

net/core: EXPORT_SYMBOL cleanups

2010-07-12 12:57:55 -07:00

netpoll.c

netpoll: Revert napi_poll fix for bonding driver

2010-10-20 01:44:30 -07:00

pktgen.c

net: core: use kernel's converter from hex to bin

2010-09-21 18:04:45 -07:00

request_sock.c

net: convert BUG_TRAP to generic WARN_ON

2008-07-25 21:43:18 -07:00

rtnetlink.c

net: copy_rtnl_link_stats64() simplification

2010-08-23 20:43:16 -07:00

scm.c

net/core: EXPORT_SYMBOL cleanups

2010-07-12 12:57:55 -07:00

skbuff.c

net: allocate skbs on local node

2010-10-16 11:13:19 -07:00

sock.c

Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

2010-09-27 01:03:03 -07:00

stream.c

net: Fix the condition passed to sk_wait_event()

2010-10-03 20:41:32 -07:00

sysctl_net_core.c

net: Consistent skb timestamping

2010-05-15 23:57:10 -07:00

timestamping.c

net: support time stamping in phy devices.

2010-07-18 19:15:26 -07:00

user_dma.c

net/core/user_dma.c: Use frag list abstraction interfaces.

2009-06-09 00:19:10 -07:00

utils.c

net: return operator cleanup

2010-09-23 14:33:39 -07:00