Commit graph

458 commits

Author SHA1 Message Date
Arnaldo Carvalho de Melo
f190055ff5 [IPVS]: Add missing include <linux/net.h>
CC [M]  net/ipv4/ipvs/ip_vs_conn.o
  /pub/scm/linux/kernel/git/acme/net-2.6/net/ipv4/ipvs/ip_vs_conn.c: In
  function 'ip_vs_conn_new':
  /pub/scm/linux/kernel/git/acme/net-2.6/net/ipv4/ipvs/ip_vs_conn.c:606:
  warning: implicit declaration of function 'net_ratelimit'
  /pub/scm/linux/kernel/git/acme/net-2.6/net/ipv4/ipvs/ip_vs_conn.c: In
  function 'ip_vs_random_dropentry':
  /pub/scm/linux/kernel/git/acme/net-2.6/net/ipv4/ipvs/ip_vs_conn.c:810:
  warning: implicit declaration of function 'net_random'

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-01-04 02:02:20 -02:00
Arnaldo Carvalho de Melo
80e40daa47 [TCP]: syn_flood_warning is only needed if CONFIG_SYN_COOKIES is selected
CC      net/ipv4/tcp_ipv4.o
  /pub/scm/linux/kernel/git/acme/net-2.6/net/ipv4/tcp_ipv4.c:665: warning:
  'syn_flood_warning' defined but not used

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-01-04 01:58:06 -02:00
Stephen Hemminger
40efc6fa17 [TCP]: less inline's
TCP inline usage cleanup:
 * get rid of inline in several places
 * replace __inline__ with inline where possible
 * move functions used in one file out of tcp.h
 * let compiler decide on used once cases

On x86_64: 
   text	   data	    bss	    dec	    hex	filename
3594701	 648348	 567400	4810449	 4966d1	vmlinux.orig
3593133	 648580	 567400	4809113	 496199	vmlinux

On sparc64:
   text	   data	    bss	    dec	    hex	filename
2538278	 406152	 530392	3474822	 350586	vmlinux.ORIG
2536382	 406384	 530392	3473158	 34ff06	vmlinux

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 16:03:49 -08:00
Stephen Hemminger
cd8787ab04 [IPV4] fib_trie: build fix
Need this to fix build of fib_trie in net-2.6.16 (rebased) tree.
The code needs the new inet_make_mask inline.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 14:38:34 -08:00
Roberto Nibali
4b5bdf5cc3 [IPVS]: Cleanup IP_VS_DBG statements.
From: Roberto Nibali <ratz@drugphish.ch>

The attached patch (against current -GIT) is a cleanup patch which does
following:

o lookup debug messages shifted back to 9
o added more informational value to flags and refcnt since those
entries can be in multiple referenced structures
o cleanup 80 char violation

It's the prepatch to the session pool implementation and helps very much
to debug and monitor important variables and structures regarding the
threshold limitation and persistency without the thousands of lookup
messages which noone is interested in.

Signed-off-by: Horms <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 14:22:59 -08:00
Christoph Hellwig
b5e5fa5e09 [NET]: Add a dev_ioctl() fallback to sock_ioctl()
Currently all network protocols need to call dev_ioctl as the default
fallback in their ioctl implementations.  This patch adds a fallback
to dev_ioctl to sock_ioctl if the protocol returned -ENOIOCTLCMD.
This way all the procotol ioctl handlers can be simplified and we don't
need to export dev_ioctl.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 14:18:33 -08:00
Arnaldo Carvalho de Melo
14c850212e [INET_SOCK]: Move struct inet_sock & helper functions to net/inet_sock.h
To help in reducing the number of include dependencies, several files were
touched as they were getting needed headers indirectly for stuff they use.

Thanks also to Alan Menegotto for pointing out that net/dccp/proto.c had
linux/dccp.h include twice.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:21 -08:00
Eric Dumazet
90ddc4f047 [NET]: move struct proto_ops to const
I noticed that some of 'struct proto_ops' used in the kernel may share
a cache line used by locks or other heavily modified data. (default
linker alignement is 32 bytes, and L1_CACHE_LINE is 64 or 128 at
least)

This patch makes sure a 'struct proto_ops' can be declared as const,
so that all cpus can share all parts of it without false sharing.

This is not mandatory : a driver can still use a read/write structure
if it needs to (and eventually a __read_mostly)

I made a global stubstitute to change all existing occurences to make
them const.

This should reduce the possibility of false sharing on SMP, and
speedup some socket system calls.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:15 -08:00
Robert Olsson
fd9662555c [IPV4] fib_trie: Add credits.
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:10 -08:00
Stephen Hemminger
9eb2d62719 [TCP] cubic: use Newton-Raphson
Replace cube root algorithim with a faster version using Newton-Raphson.
Surprisingly, doing the scaled div64_64 is faster than a true 64 bit
division on 64 bit CPU's.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:09 -08:00
Stephen Hemminger
89b3d9aaf4 [TCP] cubic: precompute constants
Revised version of patch to pre-compute values for TCP cubic.
  * d32,d64 replaced with descriptive names
  * cube_factor replaces
	 srtt[scaled by count] / HZ * ((1 << (10+2*BICTCP_HZ)) / bic_scale)
  * beta_scale replaces
	8*(BICTCP_BETA_SCALE+beta)/3/(BICTCP_BETA_SCALE-beta);

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:08 -08:00
Arnaldo Carvalho de Melo
d83d8461f9 [IP_SOCKGLUE]: Remove most of the tcp specific calls
As DCCP needs to be called in the same spots.

Now we have a member in inet_sock (is_icsk), set at sock creation time from
struct inet_protosw->flags (if INET_PROTOSW_ICSK is set, like for TCP and
DCCP) to see if a struct sock instance is a inet_connection_sock for places
like the ones in ip_sockglue.c (v4 and v6) where we previously were looking if
sk_type was SOCK_STREAM, that is insufficient because we now use the same code
for DCCP, that has sk_type SOCK_DCCP.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:58 -08:00
Arnaldo Carvalho de Melo
a7f5e7f164 [INET]: Generalise tcp_v4_hash_connect
Renaming it to inet_hash_connect, making it possible to ditch
dccp_v4_hash_connect and share the same code with TCP instead.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:55 -08:00
Arnaldo Carvalho de Melo
6d6ee43e0b [TWSK]: Introduce struct timewait_sock_ops
So that we can share several timewait sockets related functions and
make the timewait mini sockets infrastructure closer to the request
mini sockets one.

Next changesets will take advantage of this, moving more code out of
TCP and DCCP v4 and v6 to common infrastructure.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:54 -08:00
Arnaldo Carvalho de Melo
0fa1a53e1f [IPV6]: Introduce inet6_timewait_sock
Out of tcp6_timewait_sock, that now is just an aggregation of
inet_timewait_sock and inet6_timewait_sock, using tw_ipv6_offset in struct
inet_timewait_sock, that is common to the IPv6 transport protocols that use
timewait sockets, like DCCP and TCP.

tw_ipv6_offset plays the struct inet_sock pinfo6 role, i.e. for the generic
code to find the IPv6 area in a timewait sock.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:47 -08:00
Roberto Nibali
f1f71e03b1 [IPVS]: remove dead code
This patch removes dead code. I don't see the reason to keep this cruft
around, besides cluttering the nice and functionally working code.

Signed-off-by: Roberto Nibali <ratz@drugphish.ch>
Signed-off-by: Horms <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:43 -08:00
Stephen Hemminger
65a45441d7 [UDP]: udp_checksum_init return value
Since udp_checksum_init always returns 0 there is no point in
having it return a value.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:42 -08:00
Herbert Xu
3305b80c21 [IP]: Simplify and consolidate MSG_PEEK error handling
When a packet is obtained from skb_recv_datagram with MSG_PEEK enabled
it is left on the socket receive queue.  This means that when we detect
a checksum error we have to be careful when trying to free the packet
as someone could have dequeued it in the time being.

Currently this delicate logic is duplicated three times between UDPv4,
UDPv6 and RAWv6.  This patch moves them into a one place and simplifies
the code somewhat.

This is based on a suggestion by Eric Dumazet.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:41 -08:00
Arnaldo Carvalho de Melo
af05dc9394 [ICSK]: Move v4_addr2sockaddr from TCP to icsk
Renaming it to inet_csk_addr2sockaddr.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:39 -08:00
Arnaldo Carvalho de Melo
8292a17a39 [ICSK]: Rename struct tcp_func to struct inet_connection_sock_af_ops
And move it to struct inet_connection_sock. DCCP will use it in the
upcoming changesets.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:38 -08:00
Arnaldo Carvalho de Melo
ca304b6104 [IPV6]: Introduce inet6_rsk()
And inet6_rsk_offset in inet_request_sock, for the same reasons as
inet_sock's pinfo6 member.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:37 -08:00
Arnaldo Carvalho de Melo
c2977c2213 [ICSK]: make inet_csk_reqsk_queue_hash_add timeout arg unsigned long
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:34 -08:00
Arnaldo Carvalho de Melo
971af18bbf [IPV6]: Reuse inet_csk_get_port in tcp_v6_get_port
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:33 -08:00
Herbert Xu
89cee8b1cb [IPV4]: Safer reassembly
Another spin of Herbert Xu's "safer ip reassembly" patch
for 2.6.16.

(The original patch is here:
http://marc.theaimsgroup.com/?l=linux-netdev&m=112281936522415&w=2
and my only contribution is to have tested it.)

This patch (optionally) does additional checks before accepting IP
fragments, which can greatly reduce the possibility of reassembling
fragments which originated from different IP datagrams.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arthur Kepner <akepner@sgi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:31 -08:00
Eric Dumazet
3183606469 [NETFILTER] ip_tables: NUMA-aware allocation
Part of a performance problem with ip_tables is that memory allocation
is not NUMA aware, but 'only' SMP aware (ie each CPU normally touch
separate cache lines)

Even with small iptables rules, the cost of this misplacement can be
high on common workloads.  Instead of using one vmalloc() area
(located in the node of the iptables process), we now allocate an area
for each possible CPU, using vmalloc_node() so that memory should be
allocated in the CPU's node if possible.

Port to arp_tables and ip6_tables by Harald Welte.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:29 -08:00
Stephen Hemminger
df3271f336 [TCP] BIC: CUBIC window growth (2.0)
Replace existing BIC version 1.1 with new version 2.0.
The main change is to replace the window growth function
with a cubic function as described in:
  http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/cubic-paper.pdf

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:28 -08:00
Stephen Hemminger
05d054503a [TCP] BIC: spelling and whitespace
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:27 -08:00
Stephen Hemminger
018da8f44c [TCP] BIC: remove low utilization code.
The latest BICTCP patch at:
http://www.csc.ncsu.edu:8080/faculty/rhee/export/bitcp/index_files/Page546.htm

disables the low_utilization feature of BICTCP because it doesn't work
in some cases. This patch removes it.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:26 -08:00
Patrick McHardy
9e999993c7 [XFRM]: Handle DCCP in xfrm{4,6}_decode_session
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-19 14:03:46 -08:00
Patrick McHardy
0476f171af [NETFILTER]: Fix NAT init order
As noticed by Phil Oester, the GRE NAT protocol helper is initialized
before the NAT core, which makes registration fail.

Change the linking order to make NAT be initialized first.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-19 13:53:09 -08:00
Herbert Xu
1542272a60 [GRE]: Fix hardware checksum modification
The skb_postpull_rcsum introduced a bug to the checksum modification.
Although the length pulled is offset bytes, the origin of the pulling
is the GRE header, not the IP header.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-14 12:55:24 -08:00
Marcus Sundberg
2f9616d4c4 [NETFILTER]: ip_nat_tftp: Fix expectation NAT
When a TFTP client is SNATed so that the port is also changed, the
port is never changed back for the expected connection.

Signed-off-by: Marcus Sundberg <marcus@ingate.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-12 15:02:48 -08:00
David S. Miller
dfb4b9dceb [TCP] Vegas: timestamp before clone
We have to store the congestion control timestamp on the SKB before we
clone it, not after.  Else we get no timestamping information at all.

tcp_transmit_skb() has been reworked so that we can do the timestamp
still in one spot, instead of at all the call sites.

Problem discovered, and initial fix, from Tom Young
<tyo@ee.unimelb.edu.au>.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-06 16:24:52 -08:00
Thomas Young
0d7bef600a [TCP] Vegas: Remove extra call to tcp_vegas_rtt_calc
Remove unneeded call to tcp_vegas_rtt_calc. The more accurate
microsecond value has already been registered prior to calling
tcp_vegas_cong_avoid.

Signed-off-by: Thomas Young <tyo@ee.mu.oz.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-06 16:17:11 -08:00
Thomas Young
5b49561381 [TCP] Vegas: stop resetting rtt every ack
Move the resetting of rtt measurements to inside the once per RTT
block of code.

Signed-off-by: Thomas Young <tyo@ee.mu.oz.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-06 16:16:34 -08:00
Patrick McHardy
2fdf1faa8e [NETFILTER]: Don't use conntrack entry after dropping the reference
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-05 13:38:16 -08:00
Patrick McHardy
266c854348 [NETFILTER]: Fix unbalanced read_unlock_bh in ctnetlink
NFA_NEST calls NFA_PUT which jumps to nfattr_failure if the skb has no
room left. We call read_unlock_bh at nfattr_failure for the NFA_PUT inside
the locked section, so move NFA_NEST inside the locked section too.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-05 13:37:33 -08:00
Patrick McHardy
a795756333 [NETFILTER]: Mark ctnetlink as EXPERIMENTAL
Should have been marked EXPERIMENTAL from the beginning, as the current
bunch of fixes show.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-05 13:36:25 -08:00
Patrick McHardy
0be7fa92ca [NETFILTER]: Fix CTA_PROTO_NUM attribute size in ctnetlink
CTA_PROTO_NUM is a u_int8_t.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-05 13:34:51 -08:00
Patrick McHardy
afe5c6bb03 [NETFILTER]: Fix ip_conntrack_flush abuse in ctnetlink
ip_conntrack_flush() used to be part of ip_conntrack_cleanup(), which needs
to drop _all_ references on module unload. Table flushed using ctnetlink
just needs to clean the table and doesn't need to flush the event cache or
wait for any references attached to skbs. Move everything but pure table
flushing back to ip_conntrack_cleanup().

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-05 13:33:50 -08:00
Pablo Neira Ayuso
8d1ca69984 [NETFILTER]: Fix incorrect argument to ip_nat_initialized() in ctnetlink
ip_nat_initialized() takes enum ip_nat_manip_type as it's second argument,
not a hook number.

Noticed and initial patch by Marcus Sundberg <marcus@ingate.com>.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-05 13:32:14 -08:00
Herbert Xu
86c8f9d158 [IPV4] Fix EPROTONOSUPPORT error in inet_create
There is a coding error in inet_create that causes it to always return
ESOCKTNOSUPPORT.  It should return EPROTONOSUPPORT when there are
protocols registered for a given socket type but none of them match
the requested protocol.

This is based on a patch by Jayachandran C.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-02 20:43:26 -08:00
David Stevens
24c6927505 [IGMP]: workaround for IGMP v1/v2 bug
From: David Stevens <dlstevens@us.ibm.com>

As explained at:

	http://www.cs.ucsb.edu/~krishna/igmp_dos/

With IGMP version 1 and 2 it is possible to inject a unicast
report to a client which will make it ignore multicast
reports sent later by the router.

The fix is to only accept the report if is was sent to a
multicast or unicast address.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-02 20:32:59 -08:00
Thomas Graf
ea86575eaf [NETLINK]: Fix processing of fib_lookup netlink messages
The receive path for fib_lookup netlink messages is lacking sanity
checks for header and payload and is thus vulnerable to malformed
netlink messages causing illegal memory references.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-01 14:30:00 -08:00
Phil Oester
2a43c4af3f [NETFILTER]: Fix recent match jiffies wrap mismatches
Around jiffies wrap time (i.e. within first 5 mins after boot), recent
match rules which contain both --seconds and --hitcount arguments
experience false matches.

This is because the last_pkts array is filled with zeros on creation, and
when comparing 'now' to 0 (+ --seconds argument), time_before_eq thinks it
has found a hit.

Below patch adds a break if the packet value is zero.  This has the
unfortunate side effect of causing mismatches if a packet was received
when jiffies really was equal to zero.  The odds of that happening are
slim compared to the problems caused by not adding the break however.
Plus, the author used this same method just below, so it is "good enough".

This fixes netfilter bugs #383 and #395.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-01 14:29:24 -08:00
Jozsef Kadlecsik
73f306024c [NETFILTER]: Ignore ACKs ACKs on half open connections in TCP conntrack
Mounting NFS file systems after a (warm) reboot could take a long time if
firewalling and connection tracking was enabled.

The reason is that the NFS clients tends to use the same ports (800 and
counting down). Now on reboot, the server would still have a TCB for an
existing TCP connection client:800 -> server:2049. The client sends a
SYN from port 800 to server:2049, which elicits an ACK from the server.
The firewall on the client drops the ACK because (from its point of
view) the connection is still in half-open state, and it expects to see
a SYNACK.

The client will eventually time out after several minutes.

The following patch corrects this, by accepting ACKs on half open
connections as well.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-12-01 14:28:58 -08:00
Adrian Bunk
d127e94a5c [NETFILTER] ipv4: small cleanups
This patch contains the following cleanups:
- make needlessly global code static
- ip_conntrack_core.c: ip_conntrack_flush() -> ip_conntrack_flush(void)

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-29 16:28:18 -08:00
Adrian Bunk
4b30b1c6a3 [IPV4]: make two functions static
This patch makes two needlessly global functions static.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-29 16:27:20 -08:00
Arjan van de Ven
9b5b5cff9a [NET]: Add const markers to various variables.
the patch below marks various variables const in net/; the goal is to
move them to the .rodata section so that they can't false-share
cachelines with things that get written to, as well as potentially
helping gcc a bit with optimisations.  (these were found using a gcc
patch to warn about such variables)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-29 16:21:38 -08:00
Mike Stroyan
18955cfcb2 [IPV4] tcp/route: Another look at hash table sizes
The tcp_ehash hash table gets too big on systems with really big memory.
It is worse on systems with pages larger than 4KB.  It wastes memory that
could be better used.  It also makes the netstat command slow because reading
/proc/net/tcp and /proc/net/tcp6 needs to go through the full hash table.

  The default value should not be larger for larger page sizes.  It seems
that the effect of page size is an unintended error dating back a long
time.  I also wonder if the default value really should be a larger
fraction of memory for systems with more memory.  While systems with
really big ram can afford more space for hash tables, it is not clear to
me that they benefit from increasing the allocation ratio for this table.

  The amount of memory allocated is determined by net/ipv4/tcp.c:tcp_init and
mm/page_alloc.c:alloc_large_system_hash.

tcp_init calls alloc_large_system_hash passing parameters-
    bucketsize=sizeof(struct tcp_ehash_bucket)
    numentries=thash_entries
    scale=(num_physpages >= 128 * 1024) ? (25-PAGE_SHIFT) : (27-PAGE_SHIFT)
    limit=0

On i386, PAGE_SHIFT is 12 for a page size of 4K
On ia64, PAGE_SHIFT defaults to 14 for a page size of 16K

The num_physpages test above makes the allocation take a larger fraction
of the total memory on systems with larger memory.  The threshold size
for a i386 system is 512MB.  For an ia64 system with 16KB pages the
threshold is 2GB.

For smaller memory systems-
On i386, scale = (27 - 12) = 15
On ia64, scale = (27 - 14) = 13
For larger memory systems-
On i386, scale = (25 - 12) = 13
On ia64, scale = (25 - 14) = 11

  For the rest of this discussion, I'll just track the larger memory case.

  The default behavior has numentries=thash_entries=0, so the allocated
size is determined by either scale or by the default limit of 1/16 of
total memory.

In alloc_large_system_hash-
|	numentries = (flags & HASH_HIGHMEM) ? nr_all_pages : nr_kernel_pages;
|	numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
|	numentries >>= 20 - PAGE_SHIFT;
|	numentries <<= 20 - PAGE_SHIFT;

  At this point, numentries is pages for all of memory, rounded up to the
nearest megabyte boundary.

|	/* limit to 1 bucket per 2^scale bytes of low memory */
|	if (scale > PAGE_SHIFT)
|		numentries >>= (scale - PAGE_SHIFT);
|	else
|		numentries <<= (PAGE_SHIFT - scale);

On i386, numentries >>= (13 - 12), so numentries is 1/8196 of
bytes of total memory.
On ia64, numentries <<= (14 - 11), so numentries is 1/2048 of
bytes of total memory.

|        log2qty = long_log2(numentries);
|
|        do {
|                size = bucketsize << log2qty;

bucketsize is 16, so size is 16 times numentries, rounded
down to a power of two.

On i386, size is 1/512 of bytes of total memory.
On ia64, size is 1/128 of bytes of total memory.

For smaller systems the results are
On i386, size is 1/2048 of bytes of total memory.
On ia64, size is 1/512 of bytes of total memory.

  The large page effect can be removed by just replacing
the use of PAGE_SHIFT with a constant of 12 in the calls to
alloc_large_system_hash.  That makes them more like the other uses of
that function from fs/inode.c and fs/dcache.c

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-29 16:12:55 -08:00