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@xxxxxxxxxx> 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]:
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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