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| author | Andy Grover <andy.grover@oracle.com> | 2009-07-17 13:13:30 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-07-20 08:03:10 -0700 |
| commit | 68cb01c1ba312add7c7cc7da1bbe98b3071904d1 (patch) | |
| tree | 2630e1ed3d2101ae88b267888621c035ca901a99 /net/rds | |
| parent | e11d912a7dd4dfe388f38ba3080a6d067a57b23d (diff) | |
| download | lwn-68cb01c1ba312add7c7cc7da1bbe98b3071904d1.tar.gz lwn-68cb01c1ba312add7c7cc7da1bbe98b3071904d1.zip | |
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>
Diffstat (limited to 'net/rds')
| -rw-r--r-- | net/rds/ib_sysctl.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/net/rds/ib_sysctl.c b/net/rds/ib_sysctl.c index d87830db93a0..84b5ffcb280f 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[] = { { |