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Commit Graph

15715 Commits

Author SHA1 Message Date
Herbert Xu
4247e161b1 netpoll: Add ndo_netpoll_setup
This patch adds ndo_netpoll_setup as the initialisation primitive
to complement ndo_netpoll_cleanup.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-15 10:58:39 -07:00
Herbert Xu
dbaa154178 netpoll: Add locking for netpoll_setup/cleanup
As it stands, netpoll_setup and netpoll_cleanup have no locking
protection whatsoever.  So chaos ensures if two entities try to
perform them on the same device.

This patch adds RTNL to the equation.  The code has been rearranged so
that bits that do not need RTNL protection are now moved to the top of
netpoll_setup.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-15 10:58:39 -07:00
Herbert Xu
de85d99eb7 netpoll: Fix RCU usage
The use of RCU in netpoll is incorrect in a number of places:

1) The initial setting is lacking a write barrier.
2) The synchronize_rcu is in the wrong place.
3) Read barriers are missing.
4) Some places are even missing rcu_read_lock.
5) npinfo is zeroed after freeing.

This patch fixes those issues.  As most users are in BH context,
this also converts the RCU usage to the BH variant.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-15 10:58:38 -07:00
Herbert Xu
36655042f9 bridge: Remove redundant npinfo NULL setting
Now that netpoll always zaps npinfo we no longer need to do it
in bridge.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-15 10:58:38 -07:00
Herbert Xu
c04ec8063d netpoll: Set npinfo to NULL even with ndo_netpoll_cleanup
Since we have to NULL npinfo regardless of whether there is a
ndo_netpoll_cleanup, it makes sense to do this unconditionally
in netpoll_cleanup rather than having every driver do it by
themselves.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-15 10:58:37 -07:00
Eric Dumazet
d6cc1d642d inetpeer: various changes
Try to reduce cache line contentions in peer management, to reduce IP
defragmentation overhead.

- peer_fake_node is marked 'const' to make sure its not modified.
  (tested with CONFIG_DEBUG_RODATA=y)

- Group variables in two structures to reduce number of dirtied cache
lines. One named "peers" for avl tree root, its number of entries, and
associated lock. (candidate for RCU conversion)

- A second one named "unused_peers" for unused list and its lock

- Add a !list_empty() test in unlink_from_unused() to avoid taking lock
when entry is not unused.

- Use atomic_dec_and_lock() in inet_putpeer() to avoid taking lock in
some cases.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-14 23:13:08 -07:00
Eric Dumazet
c68f24cc35 ipv6: RCU changes in ipv6_get_mtu() and ip6_dst_hoplimit()
Use RCU to avoid atomic ops on idev refcnt in ipv6_get_mtu()
and ip6_dst_hoplimit()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-14 23:13:07 -07:00
Eric Dumazet
f6bc7d9e47 ipv6: avoid two atomics in ipv6_rthdr_rcv()
Use __in6_dev_get() instead of in6_dev_get()/in6_dev_put()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-14 23:13:06 -07:00
David S. Miller
6b08f51624 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/ixgbe/ixgbe_ethtool.c

With merge conflict help from Stephen Rothwell.

Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-14 22:59:34 -07:00
Eric Dumazet
e8d15e6460 net: rxhash already set in __copy_skb_header
No need to copy rxhash again in __skb_clone()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-13 17:16:54 -07:00
John Fastabend
e897082fe7 net: fix deliver_no_wcard regression on loopback device
deliver_no_wcard is not being set in skb_copy_header.
In the skb_cloned case it is not being cleared and
may cause the skb to be dropped when the loopback device
pushes it back up the stack.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-13 17:12:40 -07:00
Ben Hutchings
0b5c25e8ac irttp: Print device parameters and statistics as unsigned
Device statistics have type unsigned long and several of the
device-specific parameters printed here have type __u32.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-12 18:18:33 -07:00
Ben Hutchings
be1f3c2c02 net: Enable 64-bit net device statistics on 32-bit architectures
Use struct rtnl_link_stats64 as the statistics structure.

On 32-bit architectures, insert 32 bits of padding after/before each
field of struct net_device_stats to make its layout compatible with
struct rtnl_link_stats64.  Add an anonymous union in net_device; move
stats into the union and add struct rtnl_link_stats64 stats64.

Add net_device_ops::ndo_get_stats64, implementations of which will
return a pointer to struct rtnl_link_stats64.  Drivers that implement
this operation must not update the structure asynchronously.

Change dev_get_stats() to call ndo_get_stats64 if available, and to
return a pointer to struct rtnl_link_stats64.  Change callers of
dev_get_stats() accordingly.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-12 15:51:22 -07:00
Daniel Turull
43d28b6515 pktgen: increasing transmission granularity
This patch increases the granularity of the rate generated by pktgen.
The previous version of pktgen uses micro seconds (udelay) resolution when it
was delayed causing gaps in the rates. It is changed to nanosecond (ndelay).
Now any rate is possible.

Also it allows to set, the desired rate in Mb/s or packets per second.

The documentation has been updated.

Signed-off-by: Daniel Turull <daniel.turull@gmail.com>
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-11 18:37:09 -07:00
Eric Dumazet
0c78a92fbd econet: fix locking
econet lacks proper locking. It holds econet_lock only when inserting or
deleting an entry in econet_sklist, not during lookups.

- convert econet_lock from rwlock to spinlock

- use econet_lock in ec_listening_socket() lookup

- use appropriate sock_hold() / sock_put() to avoid corruptions.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-11 18:37:08 -07:00
Eric Dumazet
c7de2cf053 pkt_sched: gen_kill_estimator() rcu fixes
gen_kill_estimator() API is incomplete or not well documented, since
caller should make sure an RCU grace period is respected before
freeing stats_lock.

This was partially addressed in commit 5d944c640b
(gen_estimator: deadlock fix), but same problem exist for all
gen_kill_estimator() users, if lock they use is not already RCU
protected.

A code review shows xt_RATEEST.c, act_api.c, act_police.c have this
problem. Other are ok because they use qdisc lock, already RCU
protected.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-11 18:37:08 -07:00
David S. Miller
62522d36d7 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-06-11 13:32:31 -07:00
David S. Miller
14599f1e34 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6
Conflicts:
	drivers/net/wireless/wl12xx/wl1271.h
	drivers/net/wireless/wl12xx/wl1271_cmd.h
2010-06-11 11:34:06 -07:00
Changli Gao
d8d1f30b95 net-next: remove useless union keyword
remove useless union keyword in rtable, rt6_info and dn_route.

Since there is only one member in a union, the union keyword isn't useful.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10 23:31:35 -07:00
Daniel Turull
07a0f0f07a pktgen: Fix accuracy of inter-packet delay.
This patch correct a bug in the delay of pktgen. 
It makes sure the inter-packet interval is accurate.

Signed-off-by: Daniel Turull <daniel.turull@gmail.com>
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10 23:08:11 -07:00
Eric Dumazet
ae638c47dc pkt_sched: gen_estimator: add a new lock
gen_kill_estimator() / gen_new_estimator() is not always called with
RTNL held.

net/netfilter/xt_RATEEST.c is one user of these API that do not hold
RTNL, so random corruptions can occur between "tc" and "iptables".

Add a new fine grained lock instead of trying to use RTNL in netfilter.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10 22:53:52 -07:00
Eric Dumazet
592fcb9dfa ip: ip_ra_control() rcu fix
commit 66018506e1 (ip: Router Alert RCU conversion) introduced RCU
lookups to ip_call_ra_chain(). It missed proper deinit phase :
When ip_ra_control() deletes an ip_ra_chain, it should make sure
ip_call_ra_chain() users can not start to use socket during the rcu
grace period. It should also delay the sock_put() after the grace
period, or we risk a premature socket freeing and corruptions, as
raw sockets are not rcu protected yet.

This delay avoids using expensive atomic_inc_not_zero() in
ip_call_ra_chain().

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10 22:47:08 -07:00
John Fastabend
597a264b1a net: deliver skbs on inactive slaves to exact matches
Currently, the accelerated receive path for VLAN's will
drop packets if the real device is an inactive slave and
is not one of the special pkts tested for in
skb_bond_should_drop().  This behavior is different then
the non-accelerated path and for pkts over a bonded vlan.

For example,

vlanx -> bond0 -> ethx

will be dropped in the vlan path and not delivered to any
packet handlers at all.  However,

bond0 -> vlanx -> ethx

and

bond0 -> ethx

will be delivered to handlers that match the exact dev,
because the VLAN path checks the real_dev which is not a
slave and netif_recv_skb() doesn't drop frames but only
delivers them to exact matches.

This patch adds a sk_buff flag which is used for tagging
skbs that would previously been dropped and allows the
skb to continue to skb_netif_recv().  Here we add
logic to check for the deliver_no_wcard flag and if it
is set only deliver to handlers that match exactly.  This
makes both paths above consistent and gives pkt handlers
a way to identify skbs that come from inactive slaves.
Without this patch in some configurations skbs will be
delivered to handlers with exact matches and in others
be dropped out right in the vlan path.

I have tested the following 4 configurations in failover modes
and load balancing modes.

# bond0 -> ethx

# vlanx -> bond0 -> ethx

# bond0 -> vlanx -> ethx

# bond0 -> ethx
            |
  vlanx -> --

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-10 22:23:34 -07:00
Eric Dumazet
00d9d6a185 ipv6: fix ICMP6_MIB_OUTERRORS
In commit 1f8438a853 (icmp: Account for ICMP out errors), I did a typo
on IPV6 side, using ICMP6_MIB_OUTMSGS instead of ICMP6_MIB_OUTERRORS

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-09 18:39:27 -07:00
Eric Dumazet
96b52e61be ipv6: mcast: RCU conversions
- ipv6_sock_mc_join() : doesnt touch dev refcount

- ipv6_sock_mc_drop() : doesnt touch dev/idev refcounts

- ip6_mc_find_dev() becomes ip6_mc_find_dev_rcu() (called from rcu),
                    and doesnt touch dev/idev refcounts

- ipv6_sock_mc_close() : doesnt touch dev/idev refcounts

- ip6_mc_source() uses ip6_mc_find_dev_rcu()

- ip6_mc_msfilter() uses ip6_mc_find_dev_rcu()

- ip6_mc_msfget() uses ip6_mc_find_dev_rcu()

- ipv6_dev_mc_dec(), ipv6_chk_mcast_addr(),
  igmp6_event_query(), igmp6_event_report(),
  mld_sendpack(), igmp6_send() dont touch idev refcount

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-09 18:06:14 -07:00
Eric Dumazet
cfa087f689 icmp: RCU conversion in icmp_address_reply()
- rcu_read_lock() already held by caller
- use __in_dev_get_rcu() instead of in_dev_get() / in_dev_put()
- remove goto out;

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-09 18:06:13 -07:00
David S. Miller
ebedb22d2b Merge branch 'num_rx_queues' of git://kernel.ubuntu.com/rtg/net-2.6 2010-06-09 16:28:25 -07:00
Dan Carpenter
aea34e7ae7 caif: fix a couple range checks
The extra ! character means that these conditions are always false.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-09 16:18:53 -07:00
Jiri Pirko
88e7594a97 phonet: use call_rcu for phonet device free
Use call_rcu rather than synchronize_rcu.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-09 16:14:25 -07:00
Tim Gardner
08c801f8d4 net: Print num_rx_queues imbalance warning only when there are allocated queues
BugLink: http://bugs.launchpad.net/bugs/591416

There are a number of network drivers (bridge, bonding, etc) that are not yet
receive multi-queue enabled and use alloc_netdev(), so don't print a
num_rx_queues imbalance warning in that case.

Also, only print the warning once for those drivers that _are_ multi-queue
enabled.

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
2010-06-09 13:46:03 -06:00
David S. Miller
327723edeb Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2010-06-09 11:13:23 -07:00
Johannes Berg
b054b747a6 mac80211: fix deauth before assoc
When we receive a deauthentication frame before
having successfully associated, we neither print
a message nor abort assocation. The former makes
it hard to debug, while the latter later causes
a warning in cfg80211 when, as will typically be
the case, association timed out.

This warning was reported by many, e.g. in
https://bugzilla.kernel.org/show_bug.cgi?id=15981,
but I couldn't initially pinpoint it. I verified
the fix by hacking hostapd to send a deauth frame
instead of an association response.

Cc: stable@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Tested-by: Miles Lane <miles.lane@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-08 14:41:54 -04:00
Juuso Oikarinen
90b726097b mac80211: Add netif state checking to ieee80211_ifa_changed
There's a window for ieee80211_ifa_changed() to get called whilst the
managed mode mutex has not been initialized when opening and stopping the
interface. Currently this causes a kernel BUG like the following:

[  132.460013] kernel BUG at /home/wifi/iwlwifi-2.6/net/mac80211/main.c:380!
[  132.460013] invalid opcode: 0000 [#1] SMP

The mutex is initialized during open(), hence once netif_running() is true,
the mutex should be valid. Fix by adding a netif_running() check to the
function.

Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-08 09:31:21 -04:00
Eric Dumazet
bb69ae049f anycast: Some RCU conversions
- dev_get_by_flags() changed to dev_get_by_flags_rcu()

- ipv6_sock_ac_join() dont touch dev & idev refcounts
- ipv6_sock_ac_drop() dont touch dev & idev refcounts
- ipv6_sock_ac_close() dont touch dev & idev refcounts
- ipv6_dev_ac_dec() dount touch idev refcount
- ipv6_chk_acast_addr() dont touch idev refcount

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 22:49:25 -07:00
Eric Dumazet
6e8b11b43b net: avoid two atomic ops in ip_rcv_options()
in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 21:49:51 -07:00
Eric Dumazet
ed7865a47d ipv4: avoid two atomic ops in ip_rt_redirect()
in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.

[ Fix build with CONFIG_IP_ROUTE_VERBOSE disabled. -DaveM ]

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 21:49:44 -07:00
Eric Dumazet
9a57a9d291 igmp: avoid two atomic ops in igmp_rcv()
in_dev_get() -> __in_dev_get_rcu() in a rcu protected function.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 21:25:21 -07:00
Eric Dumazet
66018506e1 ip: Router Alert RCU conversion
Straightforward conversion to RCU.

One rwlock becomes a spinlock, and is static.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 21:25:21 -07:00
John W. Linville
9d88477c41 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6
Conflicts:
	drivers/net/wireless/iwlwifi/iwl-core.h
2010-06-07 15:13:46 -04:00
John W. Linville
11b7c60988 mac80211: fix lock leak w/ ARP filtering and w/o CONFIG_INET
"mac80211: make ARP filtering depend on CONFIG_INET" introduced this
potential locking leak.

Reported-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-07 15:09:16 -04:00
Holger Schurig
35dd0509b2 mac80211: fix function pointer check
This makes "iw wlan0 dump survey" work again with
mac80211-based drivers that support it, e.g. ath5k.

Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-06-07 14:44:40 -04:00
Eric Dumazet
035320d547 ipmr: dont corrupt lists
ipmr_rules_exit() and ip6mr_rules_exit() free a list of items, but
forget to properly remove these items from list. List head is not
changed and still points to freed memory.

This can trigger a fault later when icmpv6_sk_exit() is called.

Fix is to either reinit list, or use list_del() to properly remove items
from list before freeing them.

bugzilla report : https://bugzilla.kernel.org/show_bug.cgi?id=16120

Introduced by commit d1db275dd3 (ipv6: ip6mr: support multiple
tables) and commit f0ad0860d0 (ipv4: ipmr: support multiple tables)

Reported-by: Alex Zhavnerchik <alex.vizor@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 02:57:14 -07:00
jamal
271c1dfa61 net: Remove unnecessary net action assertion
The extra assertion to allow packet munging only when there are
no other ptypes listening which may have worked around an old bug
is unnecessary. It is sufficient to check if the skb is cloned before
trampling on it. Thanks to Herbert Xu for being persistent and patient
in getting this across.
[Note that cloning checks and assertions are the general rule used
by tc actions (documentation/networking/tc-actions-env-rules.txt)].

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 01:10:44 -07:00
jamal
9dacaf17a6 net sched: make pedit check for clones instead
Now that the core path doesnt set OK to munge we detect
writable skbs by looking to see if they are cloned.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 01:10:43 -07:00
Changli Gao
f2a03367c0 htb: remove two unnecessary assignments
remove two unnecessary assignments

we don't need to assign NULL when initialize structure objects.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
----
 net/sched/sch_htb.c |    2 --
 1 file changed, 2 deletions(-)
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 01:08:11 -07:00
Eric Dumazet
1789a640f5 raw: avoid two atomics in xmit
Avoid two atomic ops per raw_send_hdrinc() call

Avoid two atomic ops per raw6_send_hdrinc() call

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 01:08:10 -07:00
Alex Lorca
fe33147a58 net-caif: Added missing lock validator constants
CAIF is using "xxx-AF_MAX" strings for the lock validator. It should use
its own strings.

Signed-off-by: Alex Lorca <alex.lorca@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 01:01:22 -07:00
Tom Herbert
a8b690f98b tcp: Fix slowness in read /proc/net/tcp
This patch address a serious performance issue in reading the
TCP sockets table (/proc/net/tcp).

Reading the full table is done by a number of sequential read
operations.  At each read operation, a seek is done to find the
last socket that was previously read.  This seek operation requires
that the sockets in the table need to be counted up to the current
file position, and to count each of these requires taking a lock for
each non-empty bucket.  The whole algorithm is O(n^2).

The fix is to cache the last bucket value, offset within the bucket,
and the file position returned by the last read operation.   On the
next sequential read, the bucket and offset are used to find the
last read socket immediately without needing ot scan the previous
buckets  the table.  This algorithm t read the whole table is O(n).

The improvement offered by this patch is easily show by performing
cat'ing /proc/net/tcp on a machine with a lot of connections.  With
about 182K connections in the table, I see the following:

- Without patch
time cat /proc/net/tcp > /dev/null

real	1m56.729s
user	0m0.214s
sys	1m56.344s

- With patch
time cat /proc/net/tcp > /dev/null

real	0m0.894s
user	0m0.290s
sys	0m0.594s

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-07 00:43:42 -07:00
David S. Miller
eedc765ca4 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/sfc/net_driver.h
	drivers/net/sfc/siena.c
2010-06-06 17:42:02 -07:00
Eric Dumazet
8ffb335e8d ip6mr: fix a typo in ip6mr_for_each_table()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-06 15:34:40 -07:00