linux/net/core
Eric Dumazet ef885afbf8 net: use rcu_barrier() in rollback_registered_many
netdev_wait_allrefs() waits that all references to a device vanishes.

It currently uses a _very_ pessimistic 250 ms delay between each probe.
Some users reported that no more than 4 devices can be dismantled per
second, this is a pretty serious problem for some setups.

Most of the time, a refcount is about to be released by an RCU callback,
that is still in flight because rollback_registered_many() uses a
synchronize_rcu() call instead of rcu_barrier(). Problem is visible if
number of online cpus is one, because synchronize_rcu() is then a no op.

time to remove 50 ipip tunnels on a UP machine :

before patch : real 11.910s
after patch : real 1.250s

Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reported-by: Octavian Purdila <opurdila@ixiacom.com>
Reported-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-14 14:27:29 -07:00
..
Makefile net: support time stamping in phy devices. 2010-07-18 19:15:26 -07:00
datagram.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
dev.c net: use rcu_barrier() in rollback_registered_many 2010-09-14 14:27:29 -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
drop_monitor.c drop_monitor: use genl_register_family_with_ops() 2010-07-26 20:59:42 -07:00
dst.c __dst_free(): put EXPORT_SYMBOLS after the fct 2010-07-20 13:28:03 -07:00
ethtool.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-07-07 15:59:38 -07:00
fib_rules.c net: fib_rules: mark arguments to fib_rules_register const and __net_initdata 2010-04-26 16:02:04 +02:00
filter.c net: optimize Berkeley Packet Filter (BPF) processing 2010-06-25 21:33:12 -07:00
flow.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
gen_estimator.c pkt_sched: Fix lockdep warning on est_tree_lock in gen_estimator 2010-09-02 13:22:11 -07:00
gen_stats.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
iovec.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
kmap_skb.h
link_watch.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
neighbour.c net/core: neighbour update Oops 2010-07-14 18:02:16 -07:00
net-sysfs.c sysfs: add attribute to indicate hw address assignment type 2010-07-24 20:49:29 -07:00
net-sysfs.h net: Expose all network devices in a namespaces in sysfs 2010-05-21 09:37:34 -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
net_namespace.c net: disallow to use net_assign_generic externally 2010-04-27 15:49:02 -07:00
netevent.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
netpoll.c Revert "net: remove zap_completion_queue" 2010-08-03 00:24:04 -07:00
pktgen.c net: core: don't use own hex_to_bin() method 2010-07-23 12:50:51 -07:00
request_sock.c
rtnetlink.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
scm.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00
skbuff.c gro: Re-fix different skb headrooms 2010-09-08 10:32:15 -07:00
sock.c net: this_cpu_xxx conversions 2010-07-19 15:12:51 -07:00
stream.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -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
utils.c net/core: EXPORT_SYMBOL cleanups 2010-07-12 12:57:55 -07:00