Skip to content

cloud-kernel
cloud-kernel

openanolis / cloud-kernel
1 年多 前同步成功

通知 160
Star 36
Fork 7
cloud-kernel
cloud-kernel
切换分支/标签
  1. 17 9月, 2010 2 次提交
  3. 16 9月, 2010 30 次提交
  5. 15 9月, 2010 8 次提交
    • G
      dccp ccid-3: Simplify and consolidate tx_parse_options · 37efb03f
      由 Gerrit Renker 提交于 
      This simplifies and consolidates the TX option-parsing code:

 1. The Loss Intervals option is not currently used, so dead code related to
    this option is removed. I am aware of no plans to support the option, but
    if someone wants to implement it (e.g. for inter-op tests), it is better
    to start afresh than having to also update currently unused code.

 2. The Loss Event and Receive Rate options have a lot of code in common (both
    are 32 bit, both have same length etc.), so this is consolidated.

 3. The test against GSR is not necessary, because
    - on first loading CCID3, ccid_new() zeroes out all fields in the socket;
    - ccid3_hc_tx_packet_recv() treats 0 and ~0U equivalently, due to

	pinv = opt_recv->ccid3or_loss_event_rate;
	if (pinv == ~0U || pinv == 0)
		hctx->p = 0;

    - as a result, the sequence number field is removed from opt_recv.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      37efb03f
    • G
      dccp ccid-3: remove buggy RTT-sampling history lookup · d2c72630
      由 Gerrit Renker 提交于 
      This removes the RTT-sampling function tfrc_tx_hist_rtt(), since

 1. it suffered from complex passing of return values (the return value both
    indicated successful lookup while the value doubled as RTT sample);

 2. when for some odd reason the sample value equalled 0, this triggered a bug
    warning about "bogus Ack", due to the ambiguity of the return value;

 3. on a passive host which has not sent anything the TX history is empty and
    thus will lead to unwanted "bogus Ack" warnings such as
    ccid3_hc_tx_packet_recv: server(e7b7d518): DATAACK with bogus ACK-28197148
    ccid3_hc_tx_packet_recv: server(e7b7d518): DATAACK with bogus ACK-26641606.

The fix is to replace the implicit encoding by performing the steps manually.

Furthermore, the "bogus Ack" warning has been removed, since it can actually be
triggered due to several reasons (network reordering, old packet, (3) above),
hence it is not very useful.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      d2c72630
    • G
      dccp ccid-3: A lower bound for the inter-packet scheduling algorithm · 20cbd3e1
      由 Gerrit Renker 提交于 
      This fixes a subtle bug in the calculation of the inter-packet gap and shows
that t_delta, as it is currently used, is not needed.

The algorithm from RFC 5348, 8.3 below continually computes a send time t_nom,
which is initialised with the current time t_now; t_gran = 1E6 / HZ specifies
the scheduling granularity, s the packet size, and X the sending rate:

  t_distance = t_nom - t_now;		// in microseconds
  t_delta    = min(t_ipi, t_gran) / 2;	// `delta' parameter in microseconds

  if (t_distance >= t_delta) {
	reschedule after (t_distance / 1000) milliseconds;
  } else {
  	t_ipi  = s / X;			// inter-packet interval in usec
	t_nom += t_ipi;			// compute the next send time
	send packet now;
  }

Problem:
--------
Rescheduling requires a conversion into milliseconds (sk_reset_timer()). The
highest jiffy resolution with HZ=1000 is 1 millisecond, so using a higher
granularity does not make much sense here.

As a consequence, values of t_distance < 1000 are truncated to 0. This issue
has so far been resolved by using instead

  if (t_distance >= t_delta + 1000)
	reschedule after (t_distance / 1000) milliseconds;

This is unnecessarily large, a lower bound is t_delta' = max(t_delta, 1000).
And it implies a further simplification:

 a) when HZ >= 500, then t_delta <= t_gran/2 = 10^6/(2*HZ) <= 1000, so that
    t_delta' = MAX(1000, t_delta) = 1000 (constant value);

 b) when HZ < 500, then t_delta = 1/2*MIN(rtt, t_ipi, t_gran) <= t_gran/2,
    so that 1000 <= t_delta' <= t_gran/2.

The maximum error of using a constant t_delta in (b) is less than half a jiffy.

Fix:
----
The patch replaces t_delta with a constant, whose value depends on CONFIG_HZ,
changing the above algorithm to:

  if (t_distance >= t_delta')
	reschedule after (t_distance / 1000) milliseconds;

where t_delta' = 10^6/(2*HZ) if HZ < 500, and t_delta' = 1000 otherwise.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      20cbd3e1
    • A
      X.25 remove bkl in connect · 21a45917
      由 andrew hendry 提交于 
      Connect already has socket locking.
Signed-off-by: NAndrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      21a45917
    • A
      X.25 remove bkl in accept · 141646ce
      由 Andrew Hendry 提交于 
      Accept already has socket locking.

[ Extend socket locking over TCP_LISTEN state test. -DaveM ]
Signed-off-by: NAndrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      141646ce
    • A
      X.25 remove bkl in bind · 90c27297
      由 andrew hendry 提交于 
      Accept updates socket values in 3 lines so wrapped with lock_sock.
Signed-off-by: NAndrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      90c27297
    • A
      X.25 remove bkl in listen · 25aa4efe
      由 andrew hendry 提交于 
      Listen updates socket values and needs lock_sock.
Signed-off-by: NAndrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      25aa4efe
    • J
      net/irda: Use static const char * const where possible · 55b1804c
      由 Joe Perches 提交于 
      Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      55b1804c