Commit Graph

54 Commits

Author SHA1 Message Date
Adam Langley 4389dded77 tcp: Remove redundant checks when setting eff_sacks
Remove redundant checks when setting eff_sacks and make the number of SACKs a
compile time constant. Now that the options code knows how many SACK blocks can
fit in the header, we don't need to have the SACK code guessing at it.

Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-19 00:07:02 -07:00
David S. Miller 4ae127d1b6 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:

	drivers/net/smc911x.c
2008-06-13 20:52:39 -07:00
David S. Miller ec0a196626 tcp: Revert 'process defer accept as established' changes.
This reverts two changesets, ec3c0982a2
("[TCP]: TCP_DEFER_ACCEPT updates - process as established") and
the follow-on bug fix 9ae27e0adb
("tcp: Fix slab corruption with ipv6 and tcp6fuzz").

This change causes several problems, first reported by Ingo Molnar
as a distcc-over-loopback regression where connections were getting
stuck.

Ilpo Järvinen first spotted the locking problems.  The new function
added by this code, tcp_defer_accept_check(), only has the
child socket locked, yet it is modifying state of the parent
listening socket.

Fixing that is non-trivial at best, because we can't simply just grab
the parent listening socket lock at this point, because it would
create an ABBA deadlock.  The normal ordering is parent listening
socket --> child socket, but this code path would require the
reverse lock ordering.

Next is a problem noticed by Vitaliy Gusev, he noted:

----------------------------------------
>--- a/net/ipv4/tcp_timer.c
>+++ b/net/ipv4/tcp_timer.c
>@@ -481,6 +481,11 @@ static void tcp_keepalive_timer (unsigned long data)
> 		goto death;
> 	}
>
>+	if (tp->defer_tcp_accept.request && sk->sk_state == TCP_ESTABLISHED) {
>+		tcp_send_active_reset(sk, GFP_ATOMIC);
>+		goto death;

Here socket sk is not attached to listening socket's request queue. tcp_done()
will not call inet_csk_destroy_sock() (and tcp_v4_destroy_sock() which should
release this sk) as socket is not DEAD. Therefore socket sk will be lost for
freeing.
----------------------------------------

Finally, Alexey Kuznetsov argues that there might not even be any
real value or advantage to these new semantics even if we fix all
of the bugs:

----------------------------------------
Hiding from accept() sockets with only out-of-order data only
is the only thing which is impossible with old approach. Is this really
so valuable? My opinion: no, this is nothing but a new loophole
to consume memory without control.
----------------------------------------

So revert this thing for now.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-12 16:34:35 -07:00
Ilpo Järvinen b79eeeb9e4 tcp: Reorganize tcp_sock to fill 64-bit holes & improve locality
I tried to group recovery related fields nearby (non-CA_Open related
variables, to be more accurate) so that one to three cachelines would
not be necessary in CA_Open. These are now contiguously deployed:

  struct sk_buff_head        out_of_order_queue;   /*  1968    80 */
  /* --- cacheline 32 boundary (2048 bytes) --- */
  struct tcp_sack_block      duplicate_sack[1];    /*  2048     8 */
  struct tcp_sack_block      selective_acks[4];    /*  2056    32 */
  struct tcp_sack_block      recv_sack_cache[4];   /*  2088    32 */
  /* --- cacheline 33 boundary (2112 bytes) was 8 bytes ago --- */
  struct sk_buff *           highest_sack;         /*  2120     8 */
  int                        lost_cnt_hint;        /*  2128     4 */
  int                        retransmit_cnt_hint;  /*  2132     4 */
  u32                        lost_retrans_low;     /*  2136     4 */
  u8                         reordering;           /*  2140     1 */
  u8                         keepalive_probes;     /*  2141     1 */

  /* XXX 2 bytes hole, try to pack */

  u32                        prior_ssthresh;       /*  2144     4 */
  u32                        high_seq;             /*  2148     4 */
  u32                        retrans_stamp;        /*  2152     4 */
  u32                        undo_marker;          /*  2156     4 */
  int                        undo_retrans;         /*  2160     4 */
  u32                        total_retrans;        /*  2164     4 */

...and they're then followed by URG slowpath & keepalive related
variables.

Head of the out_of_order_queue always needed for empty checks, if
that's empty (and TCP is in CA_Open), following ~200 bytes (in 64-bit)
shouldn't be necessary for anything. If only OFO queue exists but TCP
is in CA_Open, selective_acks (and possibly duplicate_sack) are
necessary besides the out_of_order_queue but the rest of the block
again shouldn't be (ie., the other direction had losses).

As the cacheline boundaries depend on many factors in the preceeding
stuff, trying to align considering them doesn't make too much sense.

Commented one ordering hazard.

There are number of low utilized u8/16s that could be combined get 2
bytes less in total so that the hole could be made to vanish (includes
at least ecn_flags, urg_data, urg_mode, frto_counter, nonagle).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-29 03:25:23 -07:00
Ilpo Järvinen 4b74944044 tcp: Make prior_ssthresh a u32
If previous window was above representable values of u16,
strange things will happen if undo with the truncated value
is called for. Alternatively, this could be fixed by some
max trickery but that would limit undoing high-speed undos.

Adds 16-bit hole but there isn't anything to fill it with.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-21 17:40:05 -07:00
Patrick McManus ec3c0982a2 [TCP]: TCP_DEFER_ACCEPT updates - process as established
Change TCP_DEFER_ACCEPT implementation so that it transitions a
connection to ESTABLISHED after handshake is complete instead of
leaving it in SYN-RECV until some data arrvies. Place connection in
accept queue when first data packet arrives from slow path.

Benefits:
  - established connection is now reset if it never makes it
   to the accept queue

 - diagnostic state of established matches with the packet traces
   showing completed handshake

 - TCP_DEFER_ACCEPT timeouts are expressed in seconds and can now be
   enforced with reasonable accuracy instead of rounding up to next
   exponential back-off of syn-ack retry.

Signed-off-by: Patrick McManus <mcmanus@ducksong.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-21 16:33:01 -07:00
Ilpo Järvinen 68f8353b48 [TCP]: Rewrite SACK block processing & sack_recv_cache use
Key points of this patch are:

  - In case new SACK information is advance only type, no skb
    processing below previously discovered highest point is done
  - Optimize cases below highest point too since there's no need
    to always go up to highest point (which is very likely still
    present in that SACK), this is not entirely true though
    because I'm dropping the fastpath_skb_hint which could
    previously optimize those cases even better. Whether that's
    significant, I'm not too sure.

Currently it will provide skipping by walking. Combined with
RB-tree, all skipping would become fast too regardless of window
size (can be done incrementally later).

Previously a number of cases in TCP SACK processing fails to
take advantage of costly stored information in sack_recv_cache,
most importantly, expected events such as cumulative ACK and new
hole ACKs. Processing on such ACKs result in rather long walks
building up latencies (which easily gets nasty when window is
huge). Those latencies are often completely unnecessary
compared with the amount of _new_ information received, usually
for cumulative ACK there's no new information at all, yet TCP
walks whole queue unnecessary potentially taking a number of
costly cache misses on the way, etc.!

Since the inclusion of highest_sack, there's a lot information
that is very likely redundant (SACK fastpath hint stuff,
fackets_out, highest_sack), though there's no ultimate guarantee
that they'll remain the same whole the time (in all unearthly
scenarios). Take advantage of this knowledge here and drop
fastpath hint and use direct access to highest SACKed skb as
a replacement.

Effectively "special cased" fastpath is dropped. This change
adds some complexity to introduce better coveraged "fastpath",
though the added complexity should make TCP behave more cache
friendly.

The current ACK's SACK blocks are compared against each cached
block individially and only ranges that are new are then scanned
by the high constant walk. For other parts of write queue, even
when in previously known part of the SACK blocks, a faster skip
function is used (if necessary at all). In addition, whenever
possible, TCP fast-forwards to highest_sack skb that was made
available by an earlier patch. In typical case, no other things
but this fast-forward and mandatory markings after that occur
making the access pattern quite similar to the former fastpath
"special case".

DSACKs are special case that must always be walked.

The local to recv_sack_cache copying could be more intelligent
w.r.t DSACKs which are likely to be there only once but that
is left to a separate patch.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:54:07 -08:00
Ilpo Järvinen fd6dad616d [TCP]: Earlier SACK block verification & simplify access to them
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:54:07 -08:00
Ilpo Järvinen a47e5a988a [TCP]: Convert highest_sack to sk_buff to allow direct access
It is going to replace the sack fastpath hint quite soon... :-)

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:54:03 -08:00
Ilpo Järvinen f78a1b3892 [TCP]: Make snd_cwnd_cnt 32-bit
Very little point of having 32-bit snd_cnwd if this is not
32-bit as well, as a number of snd_cwnd incrementation formulas
assume that snd_cwnd_cnt can be at least as large as snd_cwnd.

Whether 32-bit is useful was discussed when e0ef57cc56
was made:
  http://marc.info/?l=linux-netdev&m=117218144409825&w=2

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15 12:59:43 -07:00
Ilpo Järvinen b08d6cb22c [TCP]: Limit processing lost_retrans loop to work-to-do cases
This addition of lost_retrans_low to tcp_sock might be
unnecessary, it's not clear how often lost_retrans worker is
executed when there wasn't work to do.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11 17:36:13 -07:00
Ilpo Järvinen c79e335716 [TCP]: Comment fastpath_cnt_hint off-by-one trap
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:54:47 -07:00
Ilpo Järvinen 13dae42631 [TCP]: Update comment about highest_sack validity
This stale info came from the original idea, which proved to be
unnecessarily complex, sacked_out > 0 is easy to do and that when
it's going to be needed anyway (it _can_ be valid also when
sacked_out == 0 but there's not going to be a guarantee about it
for now).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:48:00 -07:00
Ilpo Järvinen b5860bbac7 [TCP]: Tighten tcp_sock's belt, drop left_out
It is easily calculable when needed and user are not that many
after all.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:47:55 -07:00
Ilpo Järvinen 539d243fdd [TCP]: Access to highest_sack obsoletes forward_cnt_hint
In addition, added a reference about the purpose of the loop.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:47:53 -07:00
Ilpo Järvinen d738cd8fca [TCP]: Add highest_sack seqno, points to globally highest SACK
It is guaranteed to be valid only when !tp->sacked_out. In most
cases this seqno is available in the last ACK but there is no
guarantee for that. The new fast recovery loss marking algorithm
needs this as entry point.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:47:50 -07:00
Arnaldo Carvalho de Melo 9c70220b73 [SK_BUFF]: Introduce skb_transport_header(skb)
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>
2007-04-25 22:25:31 -07:00
Arnaldo Carvalho de Melo aa8223c7bb [SK_BUFF]: Introduce tcp_hdr(), remove skb->h.th
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:25:26 -07:00
Arnaldo Carvalho de Melo ab6a5bb6b2 [TCP]: Introduce tcp_hdrlen() and tcp_optlen()
The ip_hdrlen() buddy, created to reduce the number of skb->h.th-> uses and to
avoid the longer, open coded equivalent.

Ditched a no-op in bnx2 in the process.

I wonder if we should have a BUG_ON(skb->h.th->doff < 5) in tcp_optlen()...

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:25:24 -07:00
David S. Miller e0ef57cc56 [TCP]: Make snd_cwnd_clamp a u32.
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:23:21 -07:00
Eric Dumazet 54287cc178 [TCP]: Keep copied_seq, rcv_wup and rcv_next together.
I noticed in oprofile study a cache miss in tcp_rcv_established() to read
copied_seq.

ffffffff80400a80 <tcp_rcv_established>: /* tcp_rcv_established total: 4034293  
2.0400 */

 55493  0.0281 :ffffffff80400bc9:   mov    0x4c8(%r12),%eax copied_seq
543103  0.2746 :ffffffff80400bd1:   cmp    0x3e0(%r12),%eax   rcv_nxt    

if (tp->copied_seq == tp->rcv_nxt &&
        len - tcp_header_len <= tp->ucopy.len) {

In this function, the cache line 0x4c0 -> 0x500 is used only for this
reading 'copied_seq' field.

rcv_wup and copied_seq should be next to rcv_nxt field, to lower number of
active cache lines in hot paths. (tcp_rcv_established(), tcp_poll(), ...)

As you suggested, I changed tcp_create_openreq_child() so that these fields
are changed together, to avoid adding a new store buffer stall.

Patch is 64bit friendly (no new hole because of alignment constraints)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25 22:23:21 -07:00
Baruch Even 6f74651ae6 [TCP]: Seperate DSACK from SACK fast path
Move DSACK code outside the SACK fast-path checking code. If the DSACK
determined that the information was too old we stayed with a partial cache
copied. Most likely this matters very little since the next packet will not be
DSACK and we will find it in the cache. but it's still not good form and there
is little reason to couple the two checks.

Since the SACK receive cache doesn't need the data to be in host order we also
remove the ntohl in the checking loop.

Signed-off-by: Baruch Even <baruch@ev-en.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-02-08 12:38:49 -08:00
Arnaldo Carvalho de Melo 3a137d2065 [TCP]: Renove the __ prefix on the struct tcp_sock members
As this struct is not userland visible at all.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:30:54 -08:00
Arnaldo Carvalho de Melo 2ff52f282c [TCP]: Change tcp_header_len member in tcp_sock to u16
With this we eliminate the last hole in struct tcp_sock.

End result:

[acme@newtoy net-2.6.20]$ codiff -sV /tmp/tcp.o.before net/ipv4/tcp.o
/pub/scm/linux/kernel/git/acme/net-2.6.20/net/ipv4/tcp.c:
  struct tcp_sock |   -4
    tcp_header_len;
     from: int                   /*  1000(0)     4(0) */
     to:   u16                   /*  1000(0)     2(0) */
 1 struct changed
[acme@newtoy net-2.6.20]$

Now sizeof(tcp_sock) is just...

[acme@newtoy net-2.6.20]$ pahole --sizes ../OUTPUT/qemu/net-2.6.20/net/ipv4/tcp.o | grep -w tcp_sock
struct tcp_sock: 1500 0

1500 bytes ;-)

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:30:53 -08:00
Al Viro 9981a0e36a [NET]: Annotate checksums in on-the-wire packets.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:23:26 -08:00
YOSHIFUJI Hideaki cfb6eeb4c8 [TCP]: MD5 Signature Option (RFC2385) support.
Based on implementation by Rick Payne.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:22:39 -08:00
John Heffner ae8064ac32 [TCP]: Bound TSO defer time
This patch limits the amount of time you will defer sending a TSO segment
to less than two clock ticks, or the time between two acks, whichever is
longer.

On slow links, deferring causes significant bursts.  See attached plots,
which show RTT through a 1 Mbps link with a 100 ms RTT and ~100 ms queue
for (a) non-TSO, (b) currnet TSO, and (c) patched TSO.  This burstiness
causes significant jitter, tends to overflow queues early (bad for short
queues), and makes delay-based congestion control more difficult.

Deferring by a couple clock ticks I believe will have a relatively small
impact on performance.

Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-10-18 20:36:48 -07:00
Al Viro dddc93c05d [TCP]: struct tcp_sock .pred_flags is net-endian
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-28 18:02:05 -07:00
Al Viro 269bd27e66 [TCP]: struct tcp_sack_block annotations
Some of the instances of tcp_sack_block are host-endian, some - net-endian.
Define struct tcp_sack_block_wire identical to struct tcp_sack_block
with u32 replaced with __be32; annotate uses of tcp_sack_block replacing
net-endian ones with tcp_sack_block_wire.  Change is obviously safe since
for cc(1) __be32 is typedefed to u32.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-28 18:02:04 -07:00
Al Viro 46a97324a5 [IPV4]: TCP headers annotated
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-28 18:02:03 -07:00
David Woodhouse c8a553ad7f [TCP]: Move inclusion of <linux/dmaengine.h> to correct place in <linux/tcp.h>
The new <linux/dmaengine.h> header shouldn't be included from
the !__KERNEL__ portion of tcp.h

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-23 02:07:40 -07:00
Linus Torvalds cee4cca740 Merge git://git.infradead.org/hdrcleanup-2.6
* git://git.infradead.org/hdrcleanup-2.6: (63 commits)
  [S390] __FD_foo definitions.
  Switch to __s32 types in joystick.h instead of C99 types for consistency.
  Add <sys/types.h> to headers included for userspace in <linux/input.h>
  Move inclusion of <linux/compat.h> out of user scope in asm-x86_64/mtrr.h
  Remove struct fddi_statistics from user view in <linux/if_fddi.h>
  Move user-visible parts of drivers/s390/crypto/z90crypt.h to include/asm-s390
  Revert include/media changes: Mauro says those ioctls are only used in-kernel(!)
  Include <linux/types.h> and use __uXX types in <linux/cramfs_fs.h>
  Use __uXX types in <linux/i2o_dev.h>, include <linux/ioctl.h> too
  Remove private struct dx_hash_info from public view in <linux/ext3_fs.h>
  Include <linux/types.h> and use __uXX types in <linux/affs_hardblocks.h>
  Use __uXX types in <linux/divert.h> for struct divert_blk et al.
  Use __u32 for elf_addr_t in <asm-powerpc/elf.h>, not u32. It's user-visible.
  Remove PPP_FCS from user view in <linux/ppp_defs.h>, remove __P mess entirely
  Use __uXX types in user-visible structures in <linux/nbd.h>
  Don't use 'u32' in user-visible struct ip_conntrack_old_tuple.
  Use __uXX types for S390 DASD volume label definitions which are user-visible
  S390 BIODASDREADCMB ioctl should use __u64 not u64 type.
  Remove unneeded inclusion of <linux/time.h> from <linux/ufs_fs.h>
  Fix private integer types used in V4L2 ioctls.
  ...

Manually resolve conflict in include/linux/mtd/physmap.h
2006-06-20 15:10:08 -07:00
Chris Leech 97fc2f0848 [I/OAT]: Structure changes for TCP recv offload to I/OAT
Adds an async_wait_queue and some additional fields to tcp_sock, and a
dma_cookie_t to sk_buff.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:25:48 -07:00
David Woodhouse 62c4f0a2d5 Don't include linux/config.h from anywhere else in include/
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-26 12:56:16 +01:00
John Heffner 0e7b13685f [TCP] mtu probing: move tcp-specific data out of inet_connection_sock
This moves some TCP-specific MTU probing state out of
inet_connection_sock back to tcp_sock.

Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 21:32:58 -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 2271281362 [TCP]: Move the TCPF_ enum to tcp_states.h
Upcoming patches will make, for instance, ip_sockglue.c need just this enum
and not all of tcp.h.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:57 -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
Stephen Hemminger 6a438bbe68 [TCP]: speed up SACK processing
Use "hints" to speed up the SACK processing. Various forms 
of this have been used by TCP developers (Web100, STCP, BIC)
to avoid the 2x linear search of outstanding segments.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10 17:14:59 -08:00
Stephen Hemminger 9772efb970 [TCP]: Appropriate Byte Count support
This is an updated version of the RFC3465 ABC patch originally
for Linux 2.6.11-rc4 by Yee-Ting Li. ABC is a way of counting
bytes ack'd rather than packets when updating congestion control.

The orignal ABC described in the RFC applied to a Reno style
algorithm. For advanced congestion control there is little
change after leaving slow start.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10 17:09:53 -08:00
Arnaldo Carvalho de Melo 6687e988d9 [ICSK]: Move TCP congestion avoidance members to icsk
This changeset basically moves tcp_sk()->{ca_ops,ca_state,etc} to inet_csk(),
minimal renaming/moving done in this changeset to ease review.

Most of it is just changes of struct tcp_sock * to struct sock * parameters.

With this we move to a state closer to two interesting goals:

1. Generalisation of net/ipv4/tcp_diag.c, becoming inet_diag.c, being used
   for any INET transport protocol that has struct inet_hashinfo and are
   derived from struct inet_connection_sock. Keeps the userspace API, that will
   just not display DCCP sockets, while newer versions of tools can support
   DCCP.

2. INET generic transport pluggable Congestion Avoidance infrastructure, using
   the current TCP CA infrastructure with DCCP.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:56:18 -07:00
Arnaldo Carvalho de Melo 295f7324ff [ICSK]: Introduce reqsk_queue_prune from code in tcp_synack_timer
With this we're very close to getting all of the current TCP
refactorings in my dccp-2.6 tree merged, next changeset will export
some functions needed by the current DCCP code and then dccp-2.6.git
will be born!

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:49:29 -07:00
Arnaldo Carvalho de Melo 463c84b97f [NET]: Introduce inet_connection_sock
This creates struct inet_connection_sock, moving members out of struct
tcp_sock that are shareable with other INET connection oriented
protocols, such as DCCP, that in my private tree already uses most of
these members.

The functions that operate on these members were renamed, using a
inet_csk_ prefix while not being moved yet to a new file, so as to
ease the review of these changes.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:43:19 -07:00
Arnaldo Carvalho de Melo 8feaf0c0a5 [INET]: Generalise tcp_tw_bucket, aka TIME_WAIT sockets
This paves the way to generalise the rest of the sock ID lookup
routines and saves some bytes in TCPv4 TIME_WAIT sockets on distro
kernels (where IPv6 is always built as a module):

[root@qemu ~]# grep tw_sock /proc/slabinfo
tw_sock_TCPv6  0  0  128  31  1
tw_sock_TCP    0  0   96  41  1
[root@qemu ~]#

Now if a protocol wants to use the TIME_WAIT generic infrastructure it
only has to set the sk_prot->twsk_obj_size field with the size of its
inet_timewait_sock derived sock and proto_register will create
sk_prot->twsk_slab, for now its only for INET sockets, but we can
introduce timewait_sock later if some non INET transport protocolo
wants to use this stuff.

Next changesets will take advantage of this new infrastructure to
generalise even more TCP code.

[acme@toy net-2.6.14]$ grep built-in /tmp/before.size /tmp/after.size
/tmp/before.size: 188646   11764    5068  205478   322a6 net/ipv4/built-in.o
/tmp/after.size:  188144   11764    5068  204976   320b0 net/ipv4/built-in.o
[acme@toy net-2.6.14]$

Tested with both IPv4 & IPv6 (::1 (localhost) & ::ffff:172.20.0.1
(qemu host)).

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:42:13 -07:00
Arnaldo Carvalho de Melo c752f0739f [TCP]: Move the tcp sock states to net/tcp_states.h
Lots of places just needs the states, not even linux/tcp.h, where this
enum was, needs it.

This speeds up development of the refactorings as less sources are
rebuilt when things get moved from net/tcp.h.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:41:54 -07:00
Arnaldo Carvalho de Melo a55ebcc4c4 [INET]: Move bind_hash from tcp_sk to inet_sk
This should really be in a inet_connection_sock, but I'm leaving it
for a later optimization, when some more fields common to INET
transport protocols now in tcp_sk or inet_sk will be chunked out into
inet_connection_sock, for now its better to concentrate on getting the
changes in the core merged to leave the DCCP tree with only DCCP
specific code.

Next changesets will take advantage of this move to generalise things
like tcp_bind_hash, tcp_put_port, tcp_inherit_port, making the later
receive a inet_hashinfo parameter, and even __tcp_tw_hashdance, etc in
the future, when tcp_tw_bucket gets transformed into the struct
timewait_sock hierarchy.

tcp_destroy_sock also is eligible as soon as tcp_orphan_count gets
moved to sk_prot.

A cascade of incremental changes will ultimately make the tcp_lookup
functions be fully generic.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:38:48 -07:00
Arnaldo Carvalho de Melo 0f7ff9274e [INET]: Just rename the TCP hashtable functions/structs to inet_
This is to break down the complexity of the series of patches,
making it very clear that this one just does:

1. renames tcp_ prefixed hashtable functions and data structures that
   were already mostly generic to inet_ to share it with DCCP and
   other INET transport protocols.

2. Removes not used functions (__tb_head & tb_head)

3. Removes some leftover prototypes in the headers (tcp_bucket_unlock &
   tcp_v4_build_header)

Next changesets will move tcp_sk(sk)->bind_hash to inet_sock so that we can
make functions such as tcp_inherit_port, __tcp_inherit_port, tcp_v4_get_port,
__tcp_put_port,  generic and get others like tcp_destroy_sock closer to generic
(tcp_orphan_count will go to sk->sk_prot to allow this).

Eventually most of these functions will be used passing the transport protocol
inet_hashinfo structure.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:38:32 -07:00
David S. Miller c1b4a7e695 [TCP]: Move to new TSO segmenting scheme.
Make TSO segment transmit size decisions at send time not earlier.

The basic scheme is that we try to build as large a TSO frame as
possible when pulling in the user data, but the size of the TSO frame
output to the card is determined at transmit time.

This is guided by tp->xmit_size_goal.  It is always set to a multiple
of MSS and tells sendmsg/sendpage how large an SKB to try and build.

Later, tcp_write_xmit() and tcp_push_one() chop up the packet if
necessary and conditions warrant.  These routines can also decide to
"defer" in order to wait for more ACKs to arrive and thus allow larger
TSO frames to be emitted.

A general observation is that TSO elongates the pipe, thus requiring a
larger congestion window and larger buffering especially at the sender
side.  Therefore, it is important that applications 1) get a large
enough socket send buffer (this is accomplished by our dynamic send
buffer expansion code) 2) do large enough writes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-05 15:24:38 -07:00
Stephen Hemminger 5f8ef48d24 [TCP]: Allow choosing TCP congestion control via sockopt.
Allow using setsockopt to set TCP congestion control to use on a per
socket basis.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-23 20:37:36 -07:00
Stephen Hemminger 317a76f9a4 [TCP]: Add pluggable congestion control algorithm infrastructure.
Allow TCP to have multiple pluggable congestion control algorithms.
Algorithms are defined by a set of operations and can be built in
or modules.  The legacy "new RENO" algorithm is used as a starting
point and fallback.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-23 12:19:55 -07:00