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 <>
Signed-off-by: default avatarDavid S. Miller <>
parent e11d912a
......@@ -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_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[] = {
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