Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit 68cb01c1ba312add7c7cc7da1bbe98b3071904d1

Authored by Andy Grover
Committed by David S. Miller
1 parent e11d912a7d
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

RDS/IB: Disable flow control in sysctl and explain why 

Backwards compatibility with rds 3.0 causes protocol-
based flow control to be disabled as a side-effect.

I don't want to pull out FC support from the IB transport
but I do want to document and keep the sysctl consistent
if possible.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Showing 1 changed file with 11 additions and 1 deletions Side-by-side Diff

... ... @@ -53,7 +53,17 @@
53 53 static unsigned long rds_ib_sysctl_max_unsig_bytes_min = 1;
54 54 static unsigned long rds_ib_sysctl_max_unsig_bytes_max = ~0UL;
55 55  
56   -unsigned int rds_ib_sysctl_flow_control = 1;
  56 +/*
  57 + * This sysctl does nothing.
  58 + *
  59 + * Backwards compatibility with RDS 3.0 wire protocol
  60 + * disables initial FC credit exchange.
  61 + * If it's ever possible to drop 3.0 support,
  62 + * setting this to 1 and moving init/refill of send/recv
  63 + * rings from ib_cm_connect_complete() back into ib_setup_qp()
  64 + * will cause credits to be added before protocol negotiation.
  65 + */
  66 +unsigned int rds_ib_sysctl_flow_control = 0;
57 67  
58 68 ctl_table rds_ib_sysctl_table[] = {
59 69 {