Commit Graph

2757 Commits

Author SHA1 Message Date
Simon Horman
563e94f072 ipvs: add __aquire/__release annotations to ip_vs_info_seq_start/ip_vs_info_seq_stop
This teaches sparse that the following are not problems:

make C=1
  CHECK   net/ipv4/ipvs/ip_vs_ctl.c
net/ipv4/ipvs/ip_vs_ctl.c:1793:14: warning: context imbalance in 'ip_vs_info_seq_start' - wrong count at exit
net/ipv4/ipvs/ip_vs_ctl.c:1842:13: warning: context imbalance in 'ip_vs_info_seq_stop' - unexpected unlock

Acked-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-17 10:10:42 +10:00
Simon Horman
dff630ddad ipvs: supply a valid 0 address to ip_vs_conn_new()
ip_vs_conn_new expects a union nf_inet_addr as the type for its address
parameters, not a plain integer.

This problem was detected by sparse.

make C=1
  CHECK   net/ipv4/ipvs/ip_vs_core.c
net/ipv4/ipvs/ip_vs_core.c:469:9: warning: Using plain integer as NULL pointer

Acked-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-17 10:10:42 +10:00
Simon Horman
9e691ed68d ipvs: only unlock in ip_vs_edit_service() if already locked
Jumping to out unlocks __ip_vs_svc_lock, but that lock is not taken until
after code that may jump to out.

This problem was detected by sparse.

make C=1
  CHECK   net/ipv4/ipvs/ip_vs_ctl.c
net/ipv4/ipvs/ip_vs_ctl.c:1332:2: warning: context imbalance in 'ip_vs_edit_service' - unexpected unlock

Acked-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-17 10:10:41 +10:00
Stephen Rothwell
63f2c04648 net: ip_vs_proto_{tcp,udp} build fix
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-12 23:23:50 -07:00
Simon Horman
c051a0a2c9 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 into lvs-next-2.6 2008-09-10 09:14:52 +10:00
Gerrit Renker
410e27a49b This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp"
as it accentally contained the wrong set of patches. These will be
submitted separately.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-09 13:27:22 +02:00
David S. Miller
0a68a20cc3 Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp
Conflicts:

	net/dccp/input.c
	net/dccp/options.c
2008-09-08 17:28:59 -07:00
David S. Miller
17dce5dfe3 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:

	net/mac80211/mlme.c
2008-09-08 16:59:05 -07:00
Sven Wegener
e9c0ce232e ipvs: Embed user stats structure into kernel stats structure
Instead of duplicating the fields, integrate a user stats structure into
the kernel stats structure. This is more robust when the members are
changed, because they are now automatically kept in sync.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Reviewed-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-09 09:53:08 +10:00
Sven Wegener
2206a3f5b7 ipvs: Restrict connection table size via Kconfig
Instead of checking the value in include/net/ip_vs.h, we can just
restrict the range in our Kconfig file. This will prevent values outside
of the range early.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Reviewed-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-09 09:50:55 +10:00
Julius Volz
9d7f2a2b1a IPVS: Remove incorrect ip_route_me_harder(), fix IPv6
Remove an incorrect ip_route_me_harder() that was probably a result of
merging my IPv6 patches with the local client patches. With this, IPv6+NAT
are working again.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-09 09:43:13 +10:00
Simon Horman
503e81f65a ipvs: handle PARTIAL_CHECKSUM
Now that LVS can load balance locally generated traffic, packets may come
from the loopback device and thus may have a partial checksum.

The existing code allows for the case where there is no checksum at all for
TCP, however Herbert Xu has confirmed that this is not legal.

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julius Volz <juliusv@google.com>
2008-09-09 09:36:32 +10:00
Daniel Lezcano
d315492b1a netns : fix kernel panic in timewait socket destruction
How to reproduce ?
 - create a network namespace
 - use tcp protocol and get timewait socket
 - exit the network namespace
 - after a moment (when the timewait socket is destroyed), the kernel
   panics.

# BUG: unable to handle kernel NULL pointer dereference at
0000000000000007
IP: [<ffffffff821e394d>] inet_twdr_do_twkill_work+0x6e/0xb8
PGD 119985067 PUD 11c5c0067 PMD 0
Oops: 0000 [1] SMP
CPU 1
Modules linked in: ipv6 button battery ac loop dm_mod tg3 libphy ext3 jbd
edd fan thermal processor thermal_sys sg sata_svw libata dock serverworks
sd_mod scsi_mod ide_disk ide_core [last unloaded: freq_table]
Pid: 0, comm: swapper Not tainted 2.6.27-rc2 #3
RIP: 0010:[<ffffffff821e394d>] [<ffffffff821e394d>]
inet_twdr_do_twkill_work+0x6e/0xb8
RSP: 0018:ffff88011ff7fed0 EFLAGS: 00010246
RAX: ffffffffffffffff RBX: ffffffff82339420 RCX: ffff88011ff7ff30
RDX: 0000000000000001 RSI: ffff88011a4d03c0 RDI: ffff88011ac2fc00
RBP: ffffffff823392e0 R08: 0000000000000000 R09: ffff88002802a200
R10: ffff8800a5c4b000 R11: ffffffff823e4080 R12: ffff88011ac2fc00
R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000
FS: 0000000041cbd940(0000) GS:ffff8800bff839c0(0000)
knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000007 CR3: 00000000bd87c000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 0, threadinfo ffff8800bff9e000, task
ffff88011ff76690)
Stack: ffffffff823392e0 0000000000000100 ffffffff821e3a3a
0000000000000008
0000000000000000 ffffffff821e3a61 ffff8800bff7c000 ffffffff8203c7e7
ffff88011ff7ff10 ffff88011ff7ff10 0000000000000021 ffffffff82351108
Call Trace:
<IRQ> [<ffffffff821e3a3a>] ? inet_twdr_hangman+0x0/0x9e
[<ffffffff821e3a61>] ? inet_twdr_hangman+0x27/0x9e
[<ffffffff8203c7e7>] ? run_timer_softirq+0x12c/0x193
[<ffffffff820390d1>] ? __do_softirq+0x5e/0xcd
[<ffffffff8200d08c>] ? call_softirq+0x1c/0x28
[<ffffffff8200e611>] ? do_softirq+0x2c/0x68
[<ffffffff8201a055>] ? smp_apic_timer_interrupt+0x8e/0xa9
[<ffffffff8200cad6>] ? apic_timer_interrupt+0x66/0x70
<EOI> [<ffffffff82011f4c>] ? default_idle+0x27/0x3b
[<ffffffff8200abbd>] ? cpu_idle+0x5f/0x7d


Code: e8 01 00 00 4c 89 e7 41 ff c5 e8 8d fd ff ff 49 8b 44 24 38 4c 89 e7
65 8b 14 25 24 00 00 00 89 d2 48 8b 80 e8 00 00 00 48 f7 d0 <48> 8b 04 d0
48 ff 40 58 e8 fc fc ff ff 48 89 df e8 c0 5f 04 00
RIP [<ffffffff821e394d>] inet_twdr_do_twkill_work+0x6e/0xb8
RSP <ffff88011ff7fed0>
CR2: 0000000000000007

This patch provides a function to purge all timewait sockets related
to a network namespace. The timewait sockets life cycle is not tied with
the network namespace, that means the timewait sockets stay alive while
the network namespace dies. The timewait sockets are for avoiding to
receive a duplicate packet from the network, if the network namespace is
freed, the network stack is removed, so no chance to receive any packets
from the outside world. Furthermore, having a pending destruction timer
on these sockets with a network namespace freed is not safe and will lead
to an oops if the timer callback which try to access data belonging to 
the namespace like for example in:
	inet_twdr_do_twkill_work
		-> NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED);

Purging the timewait sockets at the network namespace destruction will:
 1) speed up memory freeing for the namespace
 2) fix kernel panic on asynchronous timewait destruction

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Denis V. Lunev <den@openvz.org>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-08 13:17:27 -07:00
Simon Horman
178f5e494e IPVS: use ipv6_addr_copy()
It is standard to use ipv6_addr_copy() to fill in
the in6 element of a union nf_inet_addr snet.

Thanks to Julius Volz for pointing this out.

Cc: Brian Haley <brian.haley@hp.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julius Volz <juliusv@google.com>
2008-09-08 09:34:46 +10:00
Simon Horman
5af149cc34 IPVS: fix bogus indentation
Sorry, this was my error.
Thanks to Julius Volz for pointing it out.

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julius Volz <juliusv@google.com>
2008-09-08 09:34:45 +10:00
Sven Wegener
3bfb92f407 ipvs: Reject ipv6 link-local addresses for destinations
We can't use non-local link-local addresses for destinations, without
knowing the interface on which we can reach the address. Reject them for
now.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:45 +10:00
Sven Wegener
77eb851630 ipvs: Mark tcp/udp v4 and v6 debug functions static
They are only used in this file, so they should be static

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:44 +10:00
Sven Wegener
a5ba4bf273 ipvs: Return negative error values from ip_vs_edit_service()
Like the other code in this function does.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:44 +10:00
Sven Wegener
cd9fe6c4f0 ipvs: Use pointer to address from sync message
We want a pointer to it, not the value casted to a pointer.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:43 +10:00
Simon Horman
f2428ed5e7 ipvs: load balance ipv6 connections from a local process
This allows IPVS to load balance IPv6 connections made by a local process.
For example a proxy server running locally.

External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer

This is an extenstion to the IPv4 work done in this area
by Siim Põder and Malcolm Turnbull.

Cc: Siim Põder <siim@p6drad-teel.net>
Cc: Malcolm Turnbull <malcolm@loadbalancer.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:14 +10:00
Malcolm Turnbull
4856c84c13 ipvs: load balance IPv4 connections from a local process
This allows IPVS to load balance connections made by a local process.
For example a proxy server running locally.

External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer

Signed-off-by: Siim Põder <siim@p6drad-teel.net>
Signed-off-by: Malcolm Turnbull <malcolm@loadbalancer.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz
f94fd04140 IPVS: Allow adding IPv6 services from userspace
Allow adding IPv6 services through the genetlink interface and add checks
to see if the chosen scheduler is supported with IPv6 and whether the
supplied prefix length is sane. Make sure the service count exported via
the sockopt interface only counts IPv4 services.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz
473b23d37b IPVS: Activate IPv6 Netfilter hooks
Register the previously defined or adapted netfilter hook functions for
IPv6 as PF_INET6 hooks.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz
cfc78c5a09 IPVS: Adjust various debug outputs to use new macros
Adjust various debug outputs to use the new *_BUF macro variants for
correct output of v4/v6 addresses.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:12 +10:00
Vince Busam
09571c7ae3 IPVS: Add function to determine if IPv6 address is local
Add __ip_vs_addr_is_local_v6() to find out if an IPv6 address belongs to a
local interface. Use this function to decide whether to set the
IP_VS_CONN_F_LOCALNODE flag for IPv6 destinations.

Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:12 +10:00
Julius Volz
a0eb662f9e IPVS: Turn off FTP application helper for IPv6
Immediately return from FTP application helper and do nothing when dealing
with IPv6 packets. IPv6 is not supported by this helper yet.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:11 +10:00
Julius Volz
c6883f5873 IVPS: Disable sync daemon for IPv6 connections
Disable the sync daemon for IPv6 connections, works only with IPv4 for now.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:11 +10:00
Vince Busam
667a5f1816 IPVS: Convert procfs files for IPv6 entry output
Correctly output IPv6 connection/service/dest entries in procfs files.

Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:10 +10:00
Julius Volz
7937df1564 IPVS: Convert real server lookup functions
Convert functions for looking up destinations (real servers) to support
IPv6 services/dests.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:10 +10:00
Julius Volz
2a3b791e6e IPVS: Add/adjust Netfilter hook functions and helpers for v6
Add Netfilter hook functions or modify existing ones, if possible, to
process IPv6 packets. Some support functions are also added/modified for
this. ip_vs_nat_icmp_v6() was already added in the patch that added the v6
xmit functions, as it is called from one of them.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:09 +10:00
Julius Volz
cd17f9ed09 IPVS: Extend scheduling functions for IPv6 support
Convert ip_vs_schedule() and ip_vs_sched_persist() to support scheduling of
IPv6 connections.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:09 +10:00
Julius Volz
b3cdd2a738 IPVS: Add and bind IPv6 xmit functions
Add xmit functions for IPv6. Also add the already needed __ip_vs_get_out_rt_v6()
to ip_vs_core.c. Bind the new xmit functions to v6 connections.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz
38cdcc9a03 IPVS: Add IPv6 support to xmit() support functions
Add IPv6 support to IP_VS_XMIT() and to the xmit routing cache, introducing
a new function __ip_vs_get_out_rt_v6().

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz
28364a59f3 IPVS: Extend functions for getting/creating connections
Extend functions for getting/creating connections and connection
templates for IPv6 support and fix the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz
0bbdd42b7e IPVS: Extend protocol DNAT/SNAT and state handlers
Extend protocol DNAT/SNAT and state handlers to work with IPv6. Also
change/introduce new checksumming helper functions for this.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:07 +10:00
Julius Volz
3b047d9d04 IPVS: Add protocol debug functions for IPv6
Add protocol (TCP, UDP, AH, ESP) debug functions for IPv6 packet debug
output.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz
51ef348b14 IPVS: Add 'af' args to protocol handler functions
Add 'af' arguments to conn_schedule(), conn_in_get(), conn_out_get() and
csum_check() function pointers in struct ip_vs_protocol. Extend the
respective functions for TCP, UDP, AH and ESP and adjust the callers.

The changes in the callers need to be somewhat extensive, since they now
need to pass a filled out struct ip_vs_iphdr * to the modified functions
instead of a struct iphdr *.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz
b14198f6c1 IPVS: Add IPv6 support flag to schedulers
Add 'supports_ipv6' flag to struct ip_vs_scheduler to indicate whether a
scheduler supports IPv6. Set the flag to 1 in schedulers that work with
IPv6, 0 otherwise. This flag is checked in a later patch while trying to
add a service with a specific scheduler. Adjust debug in v6-supporting
schedulers to work with both address families.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz
3c2e0505d2 IPVS: Add v6 support to ip_vs_service_get()
Add support for selecting services based on their address family to
ip_vs_service_get() and adjust the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:05 +10:00
Julius Volz
b18610de9e IPVS: Convert __ip_vs_svc_get() and __ip_vs_fwm_get()
Add support for getting services based on their address family to
__ip_vs_service_get(), __ip_vs_fwm_get() and the helper hash function
ip_vs_svc_hashkey(). Adjust the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:05 +10:00
Julius Volz
c860c6b147 IPVS: Add internal versions of sockopt interface structs
Add extended internal versions of struct ip_vs_service_user and struct
ip_vs_dest_user (the originals can't be modified as they are part
of the old sockopt interface). Adjust ip_vs_ctl.c to work with the new
data structures and add some minor AF-awareness.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:04 +10:00
Julius Volz
e7ade46a53 IPVS: Change IPVS data structures to support IPv6 addresses
Introduce new 'af' fields into IPVS data structures for specifying an
entry's address family. Convert IP addresses to be of type union
nf_inet_addr.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:03 +10:00
Julius Volz
fab0de02fb IPVS: Add CONFIG_IP_VS_IPV6 option for IPv6 support
Add boolean config option CONFIG_IP_VS_IPV6 for enabling experimental IPv6
support in IPVS. Only visible if IPv6 support is set to 'y' or both IPv6
and IPVS are modules.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:02 +10:00
Gerrit Renker
6224877b2c tcp/dccp: Consolidate common code for RFC 3390 conversion
This patch consolidates the code common to TCP and CCID-2:
 * TCP uses RFC 3390 in a packet-oriented manner (tcp_input.c) and
 * CCID-2 uses RFC 3390 in packet-oriented manner (RFC 4341).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:39 +02:00
Breno Leitao
06770843c2 ipv: Re-enable IP when MTU > 68
Re-enable IP when the MTU gets back to a valid size. 

This patch just checks if the in_dev is NULL on a NETDEV_CHANGEMTU event
and if MTU is valid (bigger than 68), then re-enable in_dev. 

Also a function that checks valid MTU size was created.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-02 17:28:58 -07:00
David S. Miller
b171e19ed0 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:

	net/mac80211/mlme.c
2008-08-29 23:06:00 -07:00
Eric Dumazet
a627266570 ip: speedup /proc/net/rt_cache handling
When scanning route cache hash table, we can avoid taking locks for
empty buckets.  Both /proc/net/rt_cache and NETLINK RTM_GETROUTE
interface are taken into account.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-28 01:11:25 -07:00
Andi Kleen
6be547a61d inet_diag: Add empty bucket optimization to inet_diag too
Skip quickly over empty buckets in inet_diag.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-28 01:09:54 -07:00
Andi Kleen
6eac560407 tcp: Skip empty hash buckets faster in /proc/net/tcp
On most systems most of the TCP established/time-wait hash buckets are empty.
When walking the hash table for /proc/net/tcp their read locks would
always be aquired just to find out they're empty. This patch changes the code
to check first if the buckets have any entries before taking the lock, which
is much cheaper than taking a lock. Since the hash tables are large
this makes a measurable difference on processing /proc/net/tcp, 
especially on architectures with slow read_lock (e.g. PPC) 

On a 2GB Core2 system time cat /proc/net/tcp > /dev/null (with a mostly
empty hash table) goes from 0.046s to 0.005s.

On systems with slower atomics (like P4 or POWER4) or larger hash tables
(more RAM) the difference is much higher.

This can be noticeable because there are some daemons around who regularly
scan /proc/net/tcp.

Original idea for this patch from Marcus Meissner, but redone by me.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-28 01:08:02 -07:00
Hugh Dickins
d994af0d50 ipv4: mode 0555 in ipv4_skeleton
vpnc on today's kernel says Cannot open "/proc/sys/net/ipv4/route/flush":
d--------- 0 root root 0 2008-08-26 11:32 /proc/sys/net/ipv4/route
d--------- 0 root root 0 2008-08-26 19:16 /proc/sys/net/ipv4/neigh

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-27 02:35:18 -07:00