kernel/linux.git/include/net/netns/smc.h, branch linux-7.0.y

net/smc: bpf: Introduce generic hook for handshake flow

2025-11-10T19:19:41+00:00

The introduction of IPPROTO_SMC enables eBPF programs to determine whether to use SMC based on the context of socket creation, such as network namespaces, PID and comm name, etc. As a subsequent enhancement, to introduce a new generic hook that allows decisions on whether to use SMC or not at runtime, including but not limited to local/remote IP address or ports. User can write their own implememtion via bpf_struct_ops now to choose whether to use SMC or not before TCP 3rd handshake to be comleted. Signed-off-by: D. Wythe Signed-off-by: Martin KaFai Lau Reviewed-by: Dust Li Link: https://patch.msgid.link/20251107035632.115950-3-alibuda@linux.alibaba.com

net/smc: make wr buffer count configurable

2025-10-30T12:31:43+00:00

Think SMC_WR_BUF_CNT_SEND := SMC_WR_BUF_CNT used in send context and SMC_WR_BUF_CNT_RECV := 3 * SMC_WR_BUF_CNT used in recv context. Those get replaced with lgr->max_send_wr and lgr->max_recv_wr respective. Please note that although with the default sysctl values qp_attr.cap.max_send_wr == qp_attr.cap.max_recv_wr is maintained but can not be assumed to be generally true any more. I see no downside to that, but my confidence level is rather modest. Signed-off-by: Halil Pasic Reviewed-by: Sidraya Jayagond Reviewed-by: Dust Li Tested-by: Mahanta Jambigi Link: https://patch.msgid.link/20251027224856.2970019-2-pasic@linux.ibm.com Signed-off-by: Paolo Abeni

net/smc: add sysctl for max conns per lgr for SMC-R v2.1

2023-11-24T12:13:14+00:00

Add a new sysctl: net.smc.smcr_max_conns_per_lgr, which is used to control the preferred max connections per lgr for SMC-R v2.1. The default value of this sysctl is 255, and the acceptable value ranges from 16 to 255. Signed-off-by: Guangguan Wang Reviewed-by: Dust Li Signed-off-by: David S. Miller

net/smc: add sysctl for max links per lgr for SMC-R v2.1

2023-11-24T12:13:14+00:00

Add a new sysctl: net.smc.smcr_max_links_per_lgr, which is used to control the preferred max links per lgr for SMC-R v2.1. The default value of this sysctl is 2, and the acceptable value ranges from 1 to 2. Signed-off-by: Guangguan Wang Reviewed-by: Dust Li Signed-off-by: David S. Miller

net/smc: Unbind r/w buffer size from clcsock and make them tunable

2022-09-22T10:58:21+00:00

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 Signed-off-by: Paolo Abeni

net/smc: Introduce a specific sysctl for TEST_LINK time

2022-09-22T10:58:21+00:00

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 Signed-off-by: Paolo Abeni

net/smc: Introduce a sysctl for setting SMC-R buffer type

2022-07-18T10:19:17+00:00

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 Signed-off-by: David S. Miller

net/smc: add sysctl for autocorking

2022-03-01T14:25:12+00:00

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 Signed-off-by: David S. Miller

net/smc: add sysctl interface for SMC

2022-03-01T14:25:12+00:00

This patch add sysctl interface to support container environment for SMC as we talk in the mail list. Link: https://lore.kernel.org/netdev/20220224020253.GF5443@linux.alibaba.com Co-developed-by: Tony Lu Signed-off-by: Tony Lu Signed-off-by: Dust Li Signed-off-by: David S. Miller

net/smc: Add global configure for handshake limitation by netlink

2022-02-11T11:14:58+00:00

Although we can control SMC handshake limitation through socket options, which means that applications who need it must modify their code. It's quite troublesome for many existing applications. This patch modifies the global default value of SMC handshake limitation through netlink, providing a way to put constraint on handshake without modifies any code for applications. Suggested-by: Tony Lu Signed-off-by: D. Wythe Reviewed-by: Tony Lu Signed-off-by: David S. Miller