RDS/IB: Disable flow control in sysctl and explain why (68cb01c1) · Commits · 戴 / test

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>

net/rds/ib_sysctl.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -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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