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  1. 19 11月, 2016 36 次提交
  3. 18 11月, 2016 4 次提交
    • A
      netns: make struct pernet_operations::id unsigned int · c7d03a00
      由 Alexey Dobriyan 提交于 
      Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

	void f(long *p, int i)
	{
		g(p[i]);
	}

  roughly translates to

	movsx	rsi, esi
	mov	rdi, [rsi+...]
	call 	g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

	static inline void *net_generic(const struct net *net, int id)
	{
		...
		ptr = ng->ptr[id - 1];
		...
	}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
	function                                     old     new   delta
	nfsd4_lock                                  3886    3959     +73
	tipc_link_build_proto_msg                   1096    1140     +44
	mac80211_hwsim_new_radio                    2776    2808     +32
	tipc_mon_rcv                                1032    1058     +26
	svcauth_gss_legacy_init                     1413    1429     +16
	tipc_bcbase_select_primary                   379     392     +13
	nfsd4_exchange_id                           1247    1260     +13
	nfsd4_setclientid_confirm                    782     793     +11
		...
	put_client_renew_locked                      494     480     -14
	ip_set_sockfn_get                            730     716     -14
	geneve_sock_add                              829     813     -16
	nfsd4_sequence_done                          721     703     -18
	nlmclnt_lookup_host                          708     686     -22
	nfsd4_lockt                                 1085    1063     -22
	nfs_get_client                              1077    1050     -27
	tcf_bpf_init                                1106    1076     -30
	nfsd4_encode_fattr                          5997    5930     -67
	Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c7d03a00
    • E
      udp: enable busy polling for all sockets · e68b6e50
      由 Eric Dumazet 提交于 
      UDP busy polling is restricted to connected UDP sockets.

This is because sk_busy_loop() only takes care of one NAPI context.

There are cases where it could be extended.

1) Some hosts receive traffic on a single NIC, with one RX queue.

2) Some applications use SO_REUSEPORT and associated BPF filter
   to split the incoming traffic on one UDP socket per RX
queue/thread/cpu

3) Some UDP sockets are used to send/receive traffic for one flow, but
they do not bother with connect()

This patch records the napi_id of first received skb, giving more
reach to busy polling.

Tested:

lpaa23:~# echo 70 >/proc/sys/net/core/busy_read
lpaa24:~# echo 70 >/proc/sys/net/core/busy_read

lpaa23:~# for f in `seq 1 10`; do ./super_netperf 1 -H lpaa24 -t UDP_RR -l 5; done

Before patch :
   27867   28870   37324   41060   41215
   36764   36838   44455   41282   43843
After patch :
   73920   73213   70147   74845   71697
   68315   68028   75219   70082   73707
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e68b6e50
    • D
      Merge branch 'rds-ha-failover-fixes' · fcd2b0da
      由 David S. Miller 提交于 
      Sowmini Varadhan says:

====================
RDS: TCP: HA/Failover fixes

This series contains a set of fixes for bugs exposed when
we ran the following in a loop between a test machine pair:

 while (1); do
   # modprobe rds-tcp on test nodes
   # run rds-stress in bi-dir mode between test machine pair
   # modprobe -r rds-tcp on test nodes
 done

rds-stress in bi-dir mode will cause both nodes to initiate
RDS-TCP connections at almost the same instant, exposing the
bugs fixed in this series.

Without the fixes, rds-stress reports sporadic packet drops,
and packets arriving out of sequence. After the fixes,we have
been able to run the  test overnight, without any issues.

Each patch has a detailed description of the root-cause fixed
by the patch.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      fcd2b0da
    • S
      RDS: TCP: Force every connection to be initiated by numerically smaller IP address · 1a0e100f
      由 Sowmini Varadhan 提交于 
      When 2 RDS peers initiate an RDS-TCP connection simultaneously,
there is a potential for "duelling syns" on either/both sides.
See commit 241b2719 ("RDS-TCP: Reset tcp callbacks if re-using an
outgoing socket in rds_tcp_accept_one()") for a description of this
condition, and the arbitration logic which ensures that the
numerically large IP address in the TCP connection is bound to the
RDS_TCP_PORT ("canonical ordering").

The rds_connection should not be marked as RDS_CONN_UP until the
arbitration logic has converged for the following reason. The sender
may start transmitting RDS datagrams as soon as RDS_CONN_UP is set,
and since the sender removes all datagrams from the rds_connection's
cp_retrans queue based on TCP acks. If the TCP ack was sent from
a tcp socket that got reset as part of duel aribitration (but
before data was delivered to the receivers RDS socket layer),
the sender may end up prematurely freeing the datagram, and
the datagram is no longer reliably deliverable.

This patch remedies that condition by making sure that, upon
receipt of 3WH completion state change notification of TCP_ESTABLISHED
in rds_tcp_state_change, we mark the rds_connection as RDS_CONN_UP
if, and only if, the IP addresses and ports for the connection are
canonically ordered. In all other cases, rds_tcp_state_change will
force an rds_conn_path_drop(), and rds_queue_reconnect() on
both peers will restart the connection to ensure canonical ordering.

A side-effect of enforcing this condition in rds_tcp_state_change()
is that rds_tcp_accept_one_path() can now be refactored for simplicity.
It is also no longer possible to encounter an RDS_CONN_UP connection in
the arbitration logic in rds_tcp_accept_one().
Signed-off-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1a0e100f