Jia He 336c7260a7 vhost: vsock: kick send_pkt worker once device is started ... commit 0b84103062 upstream. Ning Bo reported an abnormal 2-second gap when booting Kata container [1]. The unconditional timeout was caused by VSOCK_DEFAULT_CONNECT_TIMEOUT of connecting from the client side. The vhost vsock client tries to connect an initializing virtio vsock server. The abnormal flow looks like: host-userspace vhost vsock guest vsock ============== =========== ============ connect() --------> vhost_transport_send_pkt_work() initializing | vq->private_data==NULL | will not be queued V schedule_timeout(2s) vhost_vsock_start() <--------- device ready set vq->private_data wait for 2s and failed connect() again vq->private_data!=NULL recv connecting pkt Details: 1. Host userspace sends a connect pkt, at that time, guest vsock is under initializing, hence the vhost_vsock_start has not been called. So vq->private_data==NULL, and the pkt is not been queued to send to guest 2. Then it sleeps for 2s 3. After guest vsock finishes initializing, vq->private_data is set 4. When host userspace wakes up after 2s, send connecting pkt again, everything is fine. As suggested by Stefano Garzarella, this fixes it by additional kicking the send_pkt worker in vhost_vsock_start once the virtio device is started. This makes the pending pkt sent again. After this patch, kata-runtime (with vsock enabled) boot time is reduced from 3s to 1s on a ThunderX2 arm64 server. [1] https://github.com/kata-containers/runtime/issues/1917 Reported-by: Ning Bo <n.b@live.com> Suggested-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Jia He <justin.he@arm.com> Link: https://lore.kernel.org/r/20200501043840.186557-1-justin.he@arm.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-05-10 10:31:21 +02:00
..
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Kconfig.vringh	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
net.c	vhost: Check docket sk_family instead of call getname	2020-03-05 16:43:44 +01:00
scsi.c	vhost: scsi: add weight support	2019-05-27 11:08:23 -04:00
test.c	vhost/test: stop device before reset	2019-10-13 09:38:27 -04:00
test.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
vhost.c	Revert "vhost: block speculation of translated descriptors"	2019-09-14 15:21:51 -04:00
vhost.h	Revert "vhost: access vq metadata through kernel virtual address"	2019-09-04 07:39:48 -04:00
vringh.c	vringh: fix copy direction of vringh_iov_push_kern()	2019-10-28 04:25:04 -04:00
vsock.c	vhost: vsock: kick send_pkt worker once device is started	2020-05-10 10:31:21 +02:00