As done two years ago on IP route cache table (commit
22c047ccbc) , we can avoid using one
lock per hash bucket for the huge TCP/DCCP hash tables.
On a typical x86_64 platform, this saves about 2MB or 4MB of ram, for
litle performance differences. (we hit a different cache line for the
rwlock, but then the bucket cache line have a better sharing factor
among cpus, since we dirty it less often). For netstat or ss commands
that want a full scan of hash table, we perform fewer memory accesses.
Using a 'small' table of hashed rwlocks should be more than enough to
provide correct SMP concurrency between different buckets, without
using too much memory. Sizing of this table depends on
num_possible_cpus() and various CONFIG settings.
This patch provides some locking abstraction that may ease a future
work using a different model for TCP/DCCP table.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
On systems with a very large amount of memory, the heuristics in
alloc_large_system_hash() result in a very large TCP established hash
table: 16 millions of entries for a 128 GB ia64 system. This makes
reading from /proc/net/tcp pretty slow (well over a second) and as a
result netstat is slow on these machines. I know that /proc/net/tcp is
deprecated in favor of tcp_diag, however at the moment netstat only
knows of the former.
I am skeptical that such a large TCP established hash is often needed.
Just because a system has a lot of memory doesn't imply that it will
have several millions of concurrent TCP connections. Thus I believe
that we should put an arbitrary high limit to the size of the TCP
established hash by default. Users who really need a bigger hash can
always use the thash_entries boot parameter to get more.
I propose 2 millions of entries as the arbitrary high limit. This
makes /proc/net/tcp reasonably fast on the system in question (0.2 s)
while being still large enough for me to be confident that network
performance won't suffer.
This is just one way to limit the hash size, there are others; I am not
familiar enough with the TCP code to decide which is best. Thus, I
would welcome the proposals of alternatives.
[ 2 million is still too large, thus I've modified the limit in the
change to be '512 * 1024'. -DaveM ]
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.
The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.
[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Return some useful information such as the maximum listen backlog and
the current listen backlog in the tcp_info structure and
INET_DIAG_INFO.
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hopefully captured all single statement cases under net/. I'm
not too sure if there is some policy about #includes that are
"guaranteed" (ie., in the current tree) to be available through
some other #included header, so I just added linux/kernel.h to
each changed file that didn't #include it previously.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Previously code had IsReno/IsFack defined as macros that were
local to tcp_input.c though sack_ok field has user elsewhere too
for the same purpose. This changes them to static inlines as
preferred according the current coding style and unifies the
access to sack_ok across multiple files. Magic bitops of sack_ok
for FACK and DSACK are also abstracted to functions with
appropriate names.
Note:
- One sack_ok = 1 remains but that's self explanary, i.e., it
enables sack
- Couple of !IsReno cases are changed to tcp_is_sack
- There were no users for IsDSack => I dropped it
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
As discovered by Evegniy Polyakov, if we try to sendmsg after
a connection reset, we can do incredibly stupid things.
The core issue is that inet_sendmsg() tries to autobind the
socket, but we should never do that for TCP. Instead we should
just go straight into TCP's sendmsg() code which will do all
of the necessary state and pending socket error checks.
TCP's sendpage already directly vectors to tcp_sendpage(), so this
merely brings sendmsg() in line with that.
Signed-off-by: David S. Miller <davem@davemloft.net>
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.
This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
net/ipv4/tcp.c: In function 'tcp_recvmsg':
net/ipv4/tcp.c:1111: warning: unused variable 'available'
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Leech <christopher.leech@intel.com>
The performance wins come with having the DMA copy engine doing the copies
in parallel with the context switch. If there is enough data ready on the
socket at recv time just use a regular copy.
Signed-off-by: Chris Leech <christopher.leech@intel.com>
tcp_read_sock() currently assumes that the recv_actor() only returns
number of bytes copied. For network splice receive, we may have to
return an error in some cases. So allow the actor to return a negative
error value.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This diff changes the default port range used for outgoing connections,
from "use 32768-61000 in most cases, but use N-4999 on small boxes
(where N is a multiple of 1024, depending on just *how* small the box
is)" to just "use 32768-61000 in all cases".
I don't believe there are any drawbacks to this change, and it keeps
outgoing connection ports farther away from the mess of
IANA-registered ports.
Signed-off-by: Mark Glines <mark@glines.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_out_of_resources() and tcp_close() perform the
same checking of number of orphan sockets. Move this
code into common place.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the server drops its connection, NFS client reconnects using the
same socket after disconnecting. If the new connection's SYN,ACK
doesn't contain the TCP timestamp option and the old connection's did,
tp->tcp_header_len is recomputed assuming no timestamp header but
tp->rx_opt.tstamp_ok remains set. Then tcp_build_and_update_options()
adds in a timestamp option past the end of the allocated TCP header,
overwriting TCP data, or when the data is in skb_shinfo(skb)->frags[],
overwriting skb_shinfo(skb) causing a crash soon after. (The issue was
debugged from such a crash.)
Similarly, wscale_ok and sack_ok also get set based on the SYN,ACK
packet but not reset on disconnect, since they are zeroed out at
initialization. The patch zeroes out the entire tp->rx_opt struct in
tcp_disconnect() to avoid this sort of problem.
Signed-off-by: Srinivas Aji <Aji_Srinivas@emc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This updates references to drafts in comments which must be about 10
years old. Internet draft draft-ietf-tcpimpl-prob-03.txt expired in 1998
and was replaced by RFC 2525 in March 1999.
Section 3.10 of the draft maps almost identically into section 2.17 of RFC
2525: both are entitled "Failure to RST on close with data pending", the
differences in text body amount to a typo and minor sentence change.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function is quite big and has several call sites and nothing
to collapse by compiler optimization on inlining.
Besides it's nicer to read in a in .c file.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Spring cleaning time...
There seems to be a lot of places in the network code that have
extra bogus semicolons after conditionals. Most commonly is a
bogus semicolon after: switch() { }
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_memory_pressure and tcp_socket currently share a cache line with tcp_memory_allocated, tcp_sockets_allocated.
(Very hot cache line)
It makes sense to declare these variables as __read_mostly, to avoid false sharing on SMP.
ffffffff8081d9c0 B tcp_orphan_count
ffffffff8081d9c4 B tcp_memory_allocated
ffffffff8081d9c8 B tcp_sockets_allocated
ffffffff8081d9cc B tcp_memory_pressure
ffffffff8081d9d0 b tcp_md5sig_users
ffffffff8081d9d8 b tcp_md5sig_pool
ffffffff8081d9e0 b warntime.31570
ffffffff8081d9e8 b tcp_socket
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)
Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the places where we need a pointer to the transport header, it is
still legal to touch skb->h.raw directly if just adding to,
subtracting from or setting it to another layer header.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This allows the write queue implementation to be changed,
for example, to one which allows fast interval searching.
Signed-off-by: David S. Miller <davem@davemloft.net>
Change tcp_mem initialization function. The fraction of total memory
is now a continuous function of memory size, and independent of page
size.
Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
The locking calls assumed that these code paths were only
invoked in software interrupt context, but that isn't true.
Therefore we need to use spin_{lock,unlock}_bh() throughout.
Signed-off-by: David S. Miller <davem@davemloft.net>
ehash table layout is currently this one :
First half of this table is used by sockets not in TIME_WAIT state
Second half of it is used by sockets in TIME_WAIT state.
This is non optimal because of for a given hash or socket, the two chain heads
are located in separate cache lines.
Moreover the locks of the second half are never used.
If instead of this halving, we use two list heads in inet_ehash_bucket instead
of only one, we probably can avoid one cache miss, and reduce ram usage,
particularly if sizeof(rwlock_t) is big (various CONFIG_DEBUG_SPINLOCK,
CONFIG_DEBUG_LOCK_ALLOC settings). So we still halves the table but we keep
together related chains to speedup lookups and socket state change.
In this patch I did not try to align struct inet_ehash_bucket, but a future
patch could try to make this structure have a convenient size (a power of two
or a multiple of L1_CACHE_SIZE).
I guess rwlock will just vanish as soon as RCU is plugged into ehash :) , so
maybe we dont need to scratch our heads to align the bucket...
Note : In case struct inet_ehash_bucket is not a power of two, we could
probably change alloc_large_system_hash() (in case it use __get_free_pages())
to free the unused space. It currently allocates a big zone, but the last
quarter of it could be freed. Again, this should be a temporary 'problem'.
Patch tested on ipv4 tcp only, but should be OK for IPV6 and DCCP.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It should call tcp_free_md5sig_pool() not __tcp_free_md5sig_pool()
so that it does proper refcounting.
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch contains the following possible cleanups:
- make the following needlessly global functions statis:
- ipv4/tcp.c: __tcp_alloc_md5sig_pool()
- ipv4/tcp_ipv4.c: tcp_v4_reqsk_md5_lookup()
- ipv4/udplite.c: udplite_rcv()
- ipv4/udplite.c: udplite_err()
- make the following needlessly global structs static:
- ipv4/tcp_ipv4.c: tcp_request_sock_ipv4_ops
- ipv4/tcp_ipv4.c: tcp_sock_ipv4_specific
- ipv6/tcp_ipv6.c: tcp_request_sock_ipv6_ops
- net/ipv{4,6}/udplite.c: remove inline's from static functions
(gcc should know best when to inline them)
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix up tcp_mem initial settings to take into account the size of the
hash entries (different on SMP and non-SMP systems).
Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes consideration of high memory when determining TCP
hash table sizes. Taking into account high memory results in tcp_mem
values that are too large.
Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
It does not affect either mss-sized connections (obviously) or
connections controlled by Nagle (because there is only one small
segment in flight).
The idea is to record the fact that a small segment arrives on a
connection, where one small segment has already been received and
still not-ACKed. In this case ACK is forced after tcp_recvmsg() drains
receive buffer.
In other words, it is a "soft" each-2nd-segment ACK, which is enough
to preserve ACK clock even when ABC is enabled.
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change net/core, ipv4 and ipv6 sysctl variables to __read_mostly.
Couldn't actually measure any performance increase while testing (.3%
I consider noise), but seems like the right thing to do.
Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace CHECKSUM_HW by CHECKSUM_PARTIAL (for outgoing packets, whose
checksum still needs to be completed) and CHECKSUM_COMPLETE (for
incoming packets, device supplied full checksum).
Patch originally from Herbert Xu, updated by myself for 2.6.18-rc3.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based upon guidance from Alexey Kuznetsov.
When linger2 is active, we check to see if the fin_wait2
timeout is longer than the timewait. If it is, we schedule
the keepalive timer for the difference between the timewait
timeout and the fin_wait2 timeout.
When this orphan socket is seen by tcp_keepalive_timer()
it will try to transform this fin_wait2 socket into a
fin_wait2 mini-socket, again if linger2 is active.
Not all paths were setting this initial keepalive timer correctly.
The tcp input path was doing it correctly, but tcp_close() wasn't,
potentially making the socket linger longer than it really needs to.
Signed-off-by: David S. Miller <davem@davemloft.net>
We don't want nasty Xen guests to pass a TCPv6 packet in with gso_type set
to TCPv4 or even UDP (or a packet that's both TCP and UDP).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
[IPV6]: Added GSO support for TCPv6
[NET]: Generalise TSO-specific bits from skb_setup_caps
[IPV6]: Added GSO support for TCPv6
[IPV6]: Remove redundant length check on input
[NETFILTER]: SCTP conntrack: fix crash triggered by packet without chunks
[TG3]: Update version and reldate
[TG3]: Add TSO workaround using GSO
[TG3]: Turn on hw fix for ASF problems
[TG3]: Add rx BD workaround
[TG3]: Add tg3_netif_stop() in vlan functions
[TCP]: Reset gso_segs if packet is dodgy
This patch generalises the TSO-specific bits from sk_setup_caps by adding
the sk_gso_type member to struct sock. This makes sk_setup_caps generic
so that it can be used by TCPv6 or UFO.
The only catch is that whoever uses this must provide a GSO implementation
for their protocol which I think is a fair deal :) For now UFO continues to
live without a GSO implementation which is OK since it doesn't use the sock
caps field at the moment.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds GSO support for IPv6 and TCPv6.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
I wasn't paranoid enough in verifying GSO information. A bogus gso_segs
could upset drivers as much as a bogus header would. Let's reset it in
the per-protocol gso_segment functions.
I didn't verify gso_size because that can be verified by the source of
the dodgy packets.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
When GSO packets come from an untrusted source (e.g., a Xen guest domain),
we need to verify the header integrity before passing it to the hardware.
Since the first step in GSO is to verify the header, we can reuse that
code by adding a new bit to gso_type: SKB_GSO_DODGY. Packets with this
bit set can only be fed directly to devices with the corresponding bit
NETIF_F_GSO_ROBUST. If the device doesn't have that bit, then the skb
is fed to the GSO engine which will allow the packet to be sent to the
hardware if it passes the header check.
This patch changes the sg flag to a full features flag. The same method
can be used to implement TSO ECN support. We simply have to mark packets
with CWR set with SKB_GSO_ECN so that only hardware with a corresponding
NETIF_F_TSO_ECN can accept them. The GSO engine can either fully segment
the packet, or segment the first MTU and pass the rest to the hardware for
further segmentation.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix checksum problems in the GSO code path for CHECKSUM_HW packets.
The ipv4 TCP pseudo header checksum has to be adjusted for GSO
segmented packets.
The adjustment is needed because the length field in the pseudo-header
changes. However, because we have the inequality oldlen > newlen, we
know that delta = (u16)~oldlen + newlen is still a 16-bit quantity.
This also means that htonl(delta) + th->check still fits in 32 bits.
Therefore we don't have to use csum_add on this operations.
This is based on a patch by Michael Chan <mchan@broadcom.com>.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the GSO implementation for IPv4 TCP.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet
Patrick McHardy