Since commit 833bac7ec3 ("net/smc: Fix setsockopt and sysctl to
specify same buffer size again") the SMC protocol uses its own
default values for the smc.rmem and smc.wmem sysctl variables
which are no longer derived from the TCP IPv4 buffer sizes.
Fixup the kernel documentation to reflect this change, too.
Fixes: 833bac7ec3 ("net/smc: Fix setsockopt and sysctl to specify same buffer size again")
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://lore.kernel.org/r/20231030170343.748097-1-gbayer@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Currently, SMC uses smc->sk.sk_{rcv|snd}buf to create buffers for
send buffer and RMB. And the values of buffer size are from tcp_{w|r}mem
in clcsock.
The buffer size from TCP socket doesn't fit SMC well. Generally, buffers
are usually larger than TCP for SMC-R/-D to get higher performance, for
they are different underlay devices and paths.
So this patch unbinds buffer size from TCP, and introduces two sysctl
knobs to tune them independently. Also, these knobs are per net
namespace and work for containers.
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
SMC-R tests the viability of link by sending out TEST_LINK LLC
messages over RoCE fabric when connections on link have been
idle for a time longer than keepalive interval (testlink time).
But using tcp_keepalive_time as testlink time maybe not quite
suitable because it is default no less than two hours[1], which
is too long for single link to find peer dead. The active host
will still use peer-dead link (QP) sending messages, and can't
find out until get IB_WC_RETRY_EXC_ERR error CQEs, which takes
more time than TEST_LINK timeout (SMC_LLC_WAIT_TIME) normally.
So this patch introduces a independent sysctl for SMC-R to set
link keepalive time, in order to detect link down in time. The
default value is 30 seconds.
[1] https://www.rfc-editor.org/rfc/rfc1122#page-101
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This patch introduces the sysctl smcr_buf_type for setting
the type of SMC-R sndbufs and RMBs.
Valid values includes:
- SMCR_PHYS_CONT_BUFS, which means use physically contiguous
buffers for better performance and is the default value.
- SMCR_VIRT_CONT_BUFS, which means use virtually contiguous
buffers in case of physically contiguous memory is scarce.
- SMCR_MIXED_BUFS, which means first try to use physically
contiguous buffers. If not available, then use virtually
contiguous buffers.
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stephen reported the following warning messages from smc-sysctl.rst
Documentation/networking/smc-sysctl.rst:3: WARNING: Title overline
too short.
Documentation/networking/smc-sysctl.rst: WARNING: document isn't
included in any toctree
Fix the title overline and add smc-sysctl entry into
Documentation/networking/index.rst
Fixes: 12bbb0d163 ("net/smc: add sysctl for autocorking")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220303113527.62047-1-dust.li@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This add a new sysctl: net.smc.autocorking_size
We can dynamically change the behaviour of autocorking
by change the value of autocorking_size.
Setting to 0 disables autocorking in SMC
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
