vm-virtio: Optimize vhost-user interrupt notification

Thanks to the recently introduced function notifier() in the
VirtioInterrupt trait, all vhost-user devices can now bypass
listening onto an intermediate event fd as they can provide the
actual fd responsible for triggering the interrupt directly to
the vhost-user backend.

In case the notifier does not provide the event fd, the code falls
back onto the creation of an intermediate event fd it needs to listen
to, so that it can trigger the interrupt on behalf of the backend.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit is contained in:
Sebastien Boeuf
2020-01-14 08:18:35 +01:00
committed by Samuel Ortiz
parent 1f029dd2dc
commit be421dccea
5 changed files with 41 additions and 26 deletions

View File

@@ -31,7 +31,7 @@ pub struct VhostUserEpollConfig<S: VhostUserMasterReqHandler> {
pub interrupt_cb: Arc<dyn VirtioInterrupt>,
pub kill_evt: EventFd,
pub pause_evt: EventFd,
pub vu_interrupt_list: Vec<(EventFd, Queue)>,
pub vu_interrupt_list: Vec<(Option<EventFd>, Queue)>,
pub slave_req_handler: Option<MasterReqHandler<S>>,
}
@@ -64,14 +64,16 @@ impl<S: VhostUserMasterReqHandler> VhostUserEpollHandler<S> {
for (index, vhost_user_interrupt) in self.vu_epoll_cfg.vu_interrupt_list.iter().enumerate()
{
// Add events
epoll::ctl(
epoll_fd,
epoll::ControlOptions::EPOLL_CTL_ADD,
vhost_user_interrupt.0.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, index as u64),
)
.map_err(Error::EpollCtl)?;
if let Some(eventfd) = &vhost_user_interrupt.0 {
// Add events
epoll::ctl(
epoll_fd,
epoll::ControlOptions::EPOLL_CTL_ADD,
eventfd.as_raw_fd(),
epoll::Event::new(epoll::Events::EPOLLIN, index as u64),
)
.map_err(Error::EpollCtl)?;
}
}
let kill_evt_index = self.vu_epoll_cfg.vu_interrupt_list.len();
@@ -136,15 +138,14 @@ impl<S: VhostUserMasterReqHandler> VhostUserEpollHandler<S> {
match ev_type {
x if x < kill_evt_index => {
self.vu_epoll_cfg.vu_interrupt_list[x]
.0
.read()
.map_err(Error::FailedReadingQueue)?;
if let Err(e) =
self.signal_used_queue(&self.vu_epoll_cfg.vu_interrupt_list[x].1)
{
error!("Failed to signal used queue: {:?}", e);
break 'poll;
if let Some(eventfd) = &self.vu_epoll_cfg.vu_interrupt_list[x].0 {
eventfd.read().map_err(Error::FailedReadingQueue)?;
if let Err(e) =
self.signal_used_queue(&self.vu_epoll_cfg.vu_interrupt_list[x].1)
{
error!("Failed to signal used queue: {:?}", e);
break 'poll;
}
}
}
x if kill_evt_index == x => {