Commit 68cb01c1 authored by Andy Grover's avatar Andy Grover Committed by David S. Miller
Browse files

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: default avatarAndy Grover <andy.grover@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e11d912a
...@@ -53,7 +53,17 @@ unsigned long rds_ib_sysctl_max_unsig_bytes = (16 << 20); ...@@ -53,7 +53,17 @@ unsigned long rds_ib_sysctl_max_unsig_bytes = (16 << 20);
static unsigned long rds_ib_sysctl_max_unsig_bytes_min = 1; static unsigned long rds_ib_sysctl_max_unsig_bytes_min = 1;
static unsigned long rds_ib_sysctl_max_unsig_bytes_max = ~0UL; static unsigned long rds_ib_sysctl_max_unsig_bytes_max = ~0UL;
unsigned int rds_ib_sysctl_flow_control = 1; /*
* This sysctl does nothing.
*
* Backwards compatibility with RDS 3.0 wire protocol
* disables initial FC credit exchange.
* If it's ever possible to drop 3.0 support,
* setting this to 1 and moving init/refill of send/recv
* rings from ib_cm_connect_complete() back into ib_setup_qp()
* will cause credits to be added before protocol negotiation.
*/
unsigned int rds_ib_sysctl_flow_control = 0;
ctl_table rds_ib_sysctl_table[] = { ctl_table rds_ib_sysctl_table[] = {
{ {
......
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