| Message ID | 20240710212555.1617795-1-amery.hung@bytedance.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | virtio/vsock: support datagrams | expand |
Hi Amery, On Wed, Jul 10, 2024 at 09:25:41PM GMT, Amery Hung wrote: >Hey all! > >This series introduces support for datagrams to virtio/vsock. > >It is a spin-off (and smaller version) of this series from the summer: > https://lore.kernel.org/all/cover.1660362668.git.bobby.eshleman@bytedance.com/ Cool! Thanks for restarting this work! > >Please note that this is an RFC and should not be merged until >associated changes are made to the virtio specification, which will >follow after discussion from this series. > >Another aside, the v4 of the series has only been mildly tested with a >run of tools/testing/vsock/vsock_test. Some code likely needs cleaning >up, but I'm hoping to get some of the design choices agreed upon before >spending too much time making it pretty. What are the main points where you would like an agreement? > >This series first supports datagrams in a basic form for virtio, and >then optimizes the sendpath for all datagram transports. What kind of optimization? > >The result is a very fast datagram communication protocol that >outperforms even UDP on multi-queue virtio-net w/ vhost on a variety >of multi-threaded workload samples. > >For those that are curious, some summary data comparing UDP and VSOCK >DGRAM (N=5): > > vCPUS: 16 > virtio-net queues: 16 > payload size: 4KB > Setup: bare metal + vm (non-nested) > > UDP: 287.59 MB/s > VSOCK DGRAM: 509.2 MB/s Nice! I have not tested because the series does not compile as has already been pointed out, I will test the next version. > >Some notes about the implementation... > >This datagram implementation forces datagrams to self-throttle according >to the threshold set by sk_sndbuf. It behaves similar to the credits >used by streams in its effect on throughput and memory consumption, but >it is not influenced by the receiving socket as credits are. > >The device drops packets silently. > >As discussed previously, this series introduces datagrams and defers >fairness to future work. See discussion in v2 for more context around >datagrams, fairness, and this implementation. So IIUC we are re-using the same virtqueues used by stream/seqpacket, right? I did a fast review, there's something to fix, but it looks like this can work well, so I'd start to discuss virtio spec changes ASAP. Thanks, Stefano > >Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com> >Signed-off-by: Amery Hung <amery.hung@bytedance.com> >--- >Changes in v6: >- allow empty transport in datagram vsock >- add empty transport checks in various paths >- transport layer now saves source cid and port to control buffer of skb > to remove the dependency of transport in recvmsg() >- fix virtio dgram_enqueue() by looking up the transport to be used when > using sendto(2) >- fix skb memory leaks in two places >- add dgram auto-bind test >- Link to v5: https://lore.kernel.org/r/20230413-b4-vsock-dgram-v5-0-581bd37fdb26@bytedance.com > >Changes in v5: >- teach vhost to drop dgram when a datagram exceeds the receive buffer > - now uses MSG_ERRQUEUE and depends on Arseniy's zerocopy patch: > "vsock: read from socket's error queue" >- replace multiple ->dgram_* callbacks with single ->dgram_addr_init() > callback >- refactor virtio dgram skb allocator to reduce conflicts w/ zerocopy series >- add _fallback/_FALLBACK suffix to dgram transport variables/macros >- add WARN_ONCE() for table_size / VSOCK_HASH issue >- add static to vsock_find_bound_socket_common >- dedupe code in vsock_dgram_sendmsg() using module_got var >- drop concurrent sendmsg() for dgram and defer to future series >- Add more tests > - test EHOSTUNREACH in errqueue > - test stream + dgram address collision >- improve clarity of dgram msg bounds test code >- Link to v4: https://lore.kernel.org/r/20230413-b4-vsock-dgram-v4-0-0cebbb2ae899@bytedance.com > >Changes in v4: >- style changes > - vsock: use sk_vsock(vsk) in vsock_dgram_recvmsg instead of > &sk->vsk > - vsock: fix xmas tree declaration > - vsock: fix spacing issues > - virtio/vsock: virtio_transport_recv_dgram returns void because err > unused >- sparse analysis warnings/errors > - virtio/vsock: fix unitialized skerr on destroy > - virtio/vsock: fix uninitialized err var on goto out > - vsock: fix declarations that need static > - vsock: fix __rcu annotation order >- bugs > - vsock: fix null ptr in remote_info code > - vsock/dgram: make transport_dgram a fallback instead of first > priority > - vsock: remove redundant rcu read lock acquire in getname() >- tests > - add more tests (message bounds and more) > - add vsock_dgram_bind() helper > - add vsock_dgram_connect() helper > >Changes in v3: >- Support multi-transport dgram, changing logic in connect/bind > to support VMCI case >- Support per-pkt transport lookup for sendto() case >- Fix dgram_allow() implementation >- Fix dgram feature bit number (now it is 3) >- Fix binding so dgram and connectible (cid,port) spaces are > non-overlapping >- RCU protect transport ptr so connect() calls never leave > a lockless read of the transport and remote_addr are always > in sync >- Link to v2: https://lore.kernel.org/r/20230413-b4-vsock-dgram-v2-0-079cc7cee62e@bytedance.com > > >Bobby Eshleman (14): > af_vsock: generalize vsock_dgram_recvmsg() to all transports > af_vsock: refactor transport lookup code > af_vsock: support multi-transport datagrams > af_vsock: generalize bind table functions > af_vsock: use a separate dgram bind table > virtio/vsock: add VIRTIO_VSOCK_TYPE_DGRAM > virtio/vsock: add common datagram send path > af_vsock: add vsock_find_bound_dgram_socket() > virtio/vsock: add common datagram recv path > virtio/vsock: add VIRTIO_VSOCK_F_DGRAM feature bit > vhost/vsock: implement datagram support > vsock/loopback: implement datagram support > virtio/vsock: implement datagram support > test/vsock: add vsock dgram tests > > drivers/vhost/vsock.c | 62 +- > include/linux/virtio_vsock.h | 9 +- > include/net/af_vsock.h | 24 +- > include/uapi/linux/virtio_vsock.h | 2 + > net/vmw_vsock/af_vsock.c | 343 ++++++-- > net/vmw_vsock/hyperv_transport.c | 13 - > net/vmw_vsock/virtio_transport.c | 24 +- > net/vmw_vsock/virtio_transport_common.c | 188 ++++- > net/vmw_vsock/vmci_transport.c | 61 +- > net/vmw_vsock/vsock_loopback.c | 9 +- > tools/testing/vsock/util.c | 177 +++- > tools/testing/vsock/util.h | 10 + > tools/testing/vsock/vsock_test.c | 1032 ++++++++++++++++++++--- > 13 files changed, 1638 insertions(+), 316 deletions(-) > >-- >2.20.1 >