kernel.git/net/rds/rds.h, branch linux-4.5.y

RDS: convert bind hash table to re-sizable hashtable

2015-11-02T20:36:23Z

To further improve the RDS connection scalabilty on massive systems where number of sockets grows into tens of thousands of sockets, there is a need of larger bind hashtable. Pre-allocated 8K or 16K table is not very flexible in terms of memory utilisation. The rhashtable infrastructure gives us the flexibility to grow the hashtbable based on use and also comes up with inbuilt efficient bucket(chain) handling. Reviewed-by: David Miller Signed-off-by: Santosh Shilimkar Signed-off-by: Santosh Shilimkar Signed-off-by: David S. Miller

Merge branch 'net/rds/4.3-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux

2015-10-08T11:38:37Z

Santosh Shilimkar says: ==================== RDS: connection scalability and performance improvements [v4] Re-sending the same patches from v3 again since my repost of patch 05/14 from v3 was whitespace damaged. [v3] Updated patch "[PATCH v2 05/14] RDS: defer the over_batch work to send worker" as per David Miller's comment [4] to avoid the magic value usage. Patch now makes use of already available but unused send_batch_count module parameter. Rest of the patches are same as earlier version v2 [3] [v2]: Dropped "[PATCH 05/15] RDS: increase size of hash-table to 8K" from earlier version [1]. I plan to address the hash table scalability using re-sizable hash tables as suggested by David Laight and David Miller [2] This series addresses RDS connection bottlenecks on massive workloads and improve the RDMA performance almost by 3X. RDS TCP also gets a small gain of about 12%. RDS is being used in massive systems with high scalability where several hundred thousand end points and tens of thousands of local processes are operating in tens of thousand sockets. Being RC(reliable connection), socket bind and release happens very often and any inefficiencies in bind hash look ups hurts the overall system performance. RDS bin hash-table uses global spin-lock which is the biggest bottleneck. To make matter worst, it uses rcu inside global lock for hash buckets. This is being addressed by simply using per bucket rw lock which makes the locking simple and very efficient. The hash table size is still an issue and I plan to address it by using re-sizable hash tables as suggested on the list. For RDS RDMA improvement, the completion handling is revamped so that we can do batch completions. Both send and receive completion handlers are split logically to achieve the same. RDS 8K messages being one of the key usecase, mr pool is adapted to have the 8K mrs along with default 1M mrs. And while doing this, few fixes and couple of bottlenecks seen with rds_sendmsg() are addressed. Series applies against 4.3-rc1 as well net-next. Its tested on Oracle hardware with IB fabric for both bcopy as well as RDMA mode. RDS TCP is tested with iXGB NIC. Like last time, iWARP transport is untested with these changes. The patchset is also available at below git repo: git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux.git net/rds/4.3-v3 As a side note, the IB HCA driver I used for testing misses at least 3 important patches in upstream to see the full blown IB performance and am hoping to get that in mainline with help of them. ==================== Signed-off-by: David S. Miller

RDS: Use a single TCP socket for both send and receive.

2015-10-05T10:34:51Z

Commit f711a6ae062c ("net/rds: RDS-TCP: Always create a new rds_sock for an incoming connection.") modified rds-tcp so that an incoming SYN would ignore an existing "client" TCP connection which had the local port set to the transient port. The motivation for ignoring the existing "client" connection in f711a6ae was to avoid race conditions and an endless duel of reconnect attempts triggered by a restart/abort of one of the nodes in the TCP connection. However, having separate sockets for active and passive sides is avoidable, and the simpler model of a single TCP socket for both send and receives of all RDS connections associated with that tcp socket makes for easier observability. We avoid the race conditions from f711a6ae by attempting reconnects in rds_conn_shutdown if, and only if, the (new) c_outgoing bit is set for RDS_TRANS_TCP. The c_outgoing bit is initialized in __rds_conn_create(). A side-effect of re-using the client rds_connection for an incoming SYN is the potential of encountering duelling SYNs, i.e., we have an outgoing RDS_CONN_CONNECTING socket when we get the incoming SYN. The logic to arbitrate this criss-crossing SYN exchange in rds_tcp_accept_one() has been modified to emulate the BGP state machine: the smaller IP address should back off from the connection attempt. Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller

RDS: Use per-bucket rw lock for bind hash-table

2015-09-30T16:43:25Z

One global lock protecting hash-tables with 1024 buckets isn't efficient and it shows up in a massive systems with truck loads of RDS sockets serving multiple databases. The perf data clearly highlights the contention on the rw lock in these massive workloads. When the contention gets worse, the code gets into a state where it decides to back off on the lock. So while it has disabled interrupts, it sits and backs off on this lock get. This causes the system to become sluggish and eventually all sorts of bad things happen. The simple fix is to move the lock into the hash bucket and use per-bucket lock to improve the scalability. Signed-off-by: Santosh Shilimkar Signed-off-by: Santosh Shilimkar

RDS: make sure we post recv buffers

2015-08-25T20:35:30Z

If we get an ENOMEM during rds_ib_recv_refill, we might never come back and refill again later. Patch makes sure to kick krdsd into helping out. To achieve this we add RDS_RECV_REFILL flag and update in the refill path based on that so that at least some therad will keep posting receive buffers. Since krdsd and softirq both might race for refill, we decide to schedule on work queue based on ring_low instead of ring_empty. Reviewed-by: Ajaykumar Hotchandani Signed-off-by: Santosh Shilimkar Signed-off-by: Santosh Shilimkar Signed-off-by: David S. Miller

RDS-TCP: Make RDS-TCP work correctly when it is set up in a netns other than init_net

2015-08-07T18:29:57Z

Open the sockets calling sock_create_kern() with the correct struct net pointer, and use that struct net pointer when verifying the address passed to rds_bind(). Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2015-06-24T23:49:49Z

Pull networking updates from David Miller: 1) Add TX fast path in mac80211, from Johannes Berg. 2) Add TSO/GRO support to ibmveth, from Thomas Falcon 3) Move away from cached routes in ipv6, just like ipv4, from Martin KaFai Lau. 4) Lots of new rhashtable tests, from Thomas Graf. 5) Run ingress qdisc lockless, from Alexei Starovoitov. 6) Allow servers to fetch TCP packet headers for SYN packets of new connections, for fingerprinting. From Eric Dumazet. 7) Add mode parameter to pktgen, for testing receive. From Alexei Starovoitov. 8) Cache access optimizations via simplifications of build_skb(), from Alexander Duyck. 9) Move page frag allocator under mm/, also from Alexander. 10) Add xmit_more support to hv_netvsc, from KY Srinivasan. 11) Add a counter guard in case we try to perform endless reclassify loops in the packet scheduler. 12) Extern flow dissector to be programmable and use it in new "Flower" classifier. From Jiri Pirko. 13) AF_PACKET fanout rollover fixes, performance improvements, and new statistics. From Willem de Bruijn. 14) Add netdev driver for GENEVE tunnels, from John W Linville. 15) Add ingress netfilter hooks and filtering, from Pablo Neira Ayuso. 16) Fix handling of epoll edge triggers in TCP, from Eric Dumazet. 17) Add an ECN retry fallback for the initial TCP handshake, from Daniel Borkmann. 18) Add tail call support to BPF, from Alexei Starovoitov. 19) Add several pktgen helper scripts, from Jesper Dangaard Brouer. 20) Add zerocopy support to AF_UNIX, from Hannes Frederic Sowa. 21) Favor even port numbers for allocation to connect() requests, and odd port numbers for bind(0), in an effort to help avoid ip_local_port_range exhaustion. From Eric Dumazet. 22) Add Cavium ThunderX driver, from Sunil Goutham. 23) Allow bpf programs to access skb_iif and dev->ifindex SKB metadata, from Alexei Starovoitov. 24) Add support for T6 chips in cxgb4vf driver, from Hariprasad Shenai. 25) Double TCP Small Queues default to 256K to accomodate situations like the XEN driver and wireless aggregation. From Wei Liu. 26) Add more entropy inputs to flow dissector, from Tom Herbert. 27) Add CDG congestion control algorithm to TCP, from Kenneth Klette Jonassen. 28) Convert ipset over to RCU locking, from Jozsef Kadlecsik. 29) Track and act upon link status of ipv4 route nexthops, from Andy Gospodarek. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1670 commits) bridge: vlan: flush the dynamically learned entries on port vlan delete bridge: multicast: add a comment to br_port_state_selection about blocking state net: inet_diag: export IPV6_V6ONLY sockopt stmmac: troubleshoot unexpected bits in des0 & des1 net: ipv4 sysctl option to ignore routes when nexthop link is down net: track link-status of ipv4 nexthops net: switchdev: ignore unsupported bridge flags net: Cavium: Fix MAC address setting in shutdown state drivers: net: xgene: fix for ACPI support without ACPI ip: report the original address of ICMP messages net/mlx5e: Prefetch skb data on RX net/mlx5e: Pop cq outside mlx5e_get_cqe net/mlx5e: Remove mlx5e_cq.sqrq back-pointer net/mlx5e: Remove extra spaces net/mlx5e: Avoid TX CQE generation if more xmit packets expected net/mlx5e: Avoid redundant dev_kfree_skb() upon NOP completion net/mlx5e: Remove re-assignment of wq type in mlx5e_enable_rq() net/mlx5e: Use skb_shinfo(skb)->gso_segs rather than counting them net/mlx5e: Static mapping of netdev priv resources to/from netdev TX queues net/mlx4_en: Use HW counters for rx/tx bytes/packets in PF device ...

Merge branch 'for-4.2-misc' into k.o/for-4.2

2015-06-02T13:33:22Z

rds: re-entry of rds_ib_xmit/rds_iw_xmit

2015-06-02T13:22:31Z

The BUG_ON at line 452/453 is triggered in function rds_send_xmit. 441 while (ret) { 442 tmp = min_t(int, ret, sg->length - 443 conn->c_xmit_data_off); 444 conn->c_xmit_data_off += tmp; 445 ret -= tmp; 446 if (conn->c_xmit_data_off == sg->length) { 447 conn->c_xmit_data_off = 0; 448 sg++; 449 conn->c_xmit_sg++; 450 if (ret != 0 && conn->c_xmit_sg == rm->data.op_nents) 451 printk(KERN_ERR "conn %p rm %p sg %p ret %d\n", conn, rm, sg, ret); 452 BUG_ON(ret != 0 && 453 conn->c_xmit_sg == rm->data.op_nents); 454 } 455 } it is complaining the total sent length is bigger that we want to send. rds_ib_xmit() is wrong for the second entry for the same rds_message returning wrong value. the sg and off passed by rds_send_xmit to rds_ib_xmit is based on scatterlist.offset/length, but the rds_ib_xmit action is based on scatterlist.dma_address/dma_length. in case dma_length is larger than length there is problem. for the 2nd and later entries of rds_ib_xmit for same rds_message, at least one of the following two is wrong: 1) the scatterlist to start with, the choosen one can far beyond the correct one. 2) the offset to start with within the scatterlist. fix: add op_dmasg and op_dmaoff to rm_data_op structure indicating the scatterlist and offset within the it to start with for rds_ib_xmit respectively. op_dmasg and op_dmaoff are initialized to zero when doing dma mapping for the first see of the message and are changed when filling send slots. the same applies to rds_iw_xmit too. Signed-off-by: Wengang Wang Signed-off-by: Doug Ledford

net/rds: Add setsockopt support for SO_RDS_TRANSPORT

2015-06-01T04:47:23Z

An application may deterministically attach the underlying transport for a PF_RDS socket by invoking setsockopt(2) with the SO_RDS_TRANSPORT option at the SOL_RDS level. The integer argument to setsockopt must be one of the RDS_TRANS_* transport types, e.g., RDS_TRANS_TCP. The option must be specified before invoking bind(2) on the socket, and may only be used once on the socket. An attempt to set the option on a bound socket, or to invoke the option after a successful SO_RDS_TRANSPORT attachment, will return EOPNOTSUPP. Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller