Messages in this thread | | | Date | Thu, 13 Apr 2023 15:05:48 +0200 | Subject | Re: [PATCH net-next V2 0/2] virtio-net: don't busy poll for cvq command | From | Maxime Coquelin <> |
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On 4/13/23 15:02, Maxime Coquelin wrote: > Hi Jason, > > On 4/13/23 08:40, Jason Wang wrote: >> Hi all: >> >> The code used to busy poll for cvq command which turns out to have >> several side effects: >> >> 1) infinite poll for buggy devices >> 2) bad interaction with scheduler >> >> So this series tries to use sleep instead of busy polling. In this >> version, I take a step back: the hardening part is not implemented and >> leave for future investigation. We use to aggree to use interruptible >> sleep but it doesn't work for a general workqueue. >> >> Please review. > > Thanks for working on this. > My DPDK VDUSE RFC missed to set the interrupt, as Xuan Zhou highlighted > it makes the vdpa dev add/del commands to freeze: > [<0>] device_del+0x37/0x3d0 > [<0>] device_unregister+0x13/0x60 > [<0>] unregister_virtio_device+0x11/0x20 > [<0>] device_release_driver_internal+0x193/0x200 > [<0>] bus_remove_device+0xbf/0x130 > [<0>] device_del+0x174/0x3d0 > [<0>] device_unregister+0x13/0x60 > [<0>] vdpa_nl_cmd_dev_del_set_doit+0x66/0xe0 [vdpa] > [<0>] genl_family_rcv_msg_doit.isra.0+0xb8/0x100 > [<0>] genl_rcv_msg+0x151/0x290 > [<0>] netlink_rcv_skb+0x54/0x100 > [<0>] genl_rcv+0x24/0x40 > [<0>] netlink_unicast+0x217/0x340 > [<0>] netlink_sendmsg+0x23e/0x4a0 > [<0>] sock_sendmsg+0x8f/0xa0 > [<0>] __sys_sendto+0xfc/0x170 > [<0>] __x64_sys_sendto+0x20/0x30 > [<0>] do_syscall_64+0x59/0x90 > [<0>] entry_SYSCALL_64_after_hwframe+0x72/0xdc > > Once fixed on DPDK side (you can use my vduse_v1 branch [0] for > testing), it works fine: > > Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com> > > For the potential missing interrupt with non-compliant devices, I guess > it could be handled with the hardening work as same thing could happen > if the VDUSE application crashed for example. > > Regards, > Maxime > > [0]:
Better with the link...
[0]: https://gitlab.com/mcoquelin/dpdk-next-virtio/-/commits/vduse_v1/
>> Thanks >> >> Changes since V1: >> - use RTNL to synchronize rx mode worker >> - use completion for simplicity >> - don't try to harden CVQ command >> >> Changes since RFC: >> >> - switch to use BAD_RING in virtio_break_device() >> - check virtqueue_is_broken() after being woken up >> - use more_used() instead of virtqueue_get_buf() to allow caller to >> get buffers afterwards >> - break the virtio-net device when timeout >> - get buffer manually since the virtio core check more_used() instead >> >> Jason Wang (2): >> virtio-net: convert rx mode setting to use workqueue >> virtio-net: sleep instead of busy waiting for cvq command >> >> drivers/net/virtio_net.c | 76 ++++++++++++++++++++++++++++++++++------ >> 1 file changed, 66 insertions(+), 10 deletions(-) >>
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