From: Andy Grover Date: Fri, 17 Jul 2009 13:13:30 +0000 (+0000) Subject: RDS/IB: Disable flow control in sysctl and explain why X-Git-Tag: v2.6.32-rc1~703^2~596 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=68cb01c1ba312add7c7cc7da1bbe98b3071904d1;p=~shefty%2Frdma-dev.git 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 Signed-off-by: David S. Miller --- diff --git a/net/rds/ib_sysctl.c b/net/rds/ib_sysctl.c index d87830db93a..84b5ffcb280 100644 --- a/net/rds/ib_sysctl.c +++ b/net/rds/ib_sysctl.c @@ -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[] = { {