Hi Xiangxia, > -----Original Message----- > From: [email protected] [mailto:[email protected]] > Sent: Wednesday, March 28, 2018 1:49 PM > To: Tan, Jianfeng > Cc: [email protected]; Tonghao Zhang > Subject: [PATCH 2/2] vhost: add pipe event for optimizing negotiating > > From: Tonghao Zhang <[email protected]> > > When vhost—user connects qemu successfully, dpdk will call
Typo: "-" > the vhost_user_add_connection to add unix socket fd to poll. > And fdset_add only set the socket fd to a fdentry while poll > may sleep now. In a general case, this is no problem. But if > we use hot update for vhost-user, most downtime of VMs network > is 750+ms. This patch adds pipe event, so after connections are > ok, dpdk rebuild the poll immediately. With this patch, the > most downtime is 20~30ms. > > Signed-off-by: Tonghao Zhang <[email protected]> > --- > lib/librte_vhost/fd_man.c | 49 > +++++++++++++++++++++++++++++++++++++++++++++++ > lib/librte_vhost/fd_man.h | 16 ++++++++++++++++ > lib/librte_vhost/socket.c | 14 ++++++++++++++ > 3 files changed, 79 insertions(+) > > diff --git a/lib/librte_vhost/fd_man.c b/lib/librte_vhost/fd_man.c > index 181711c..7716757 100644 > --- a/lib/librte_vhost/fd_man.c > +++ b/lib/librte_vhost/fd_man.c > @@ -15,6 +15,7 @@ > #include <rte_log.h> > > #include "fd_man.h" > +#include "vhost.h" This is a nice finding and solution, however, I don't think we shall include vhost header file in fd related files. Actually, I did not find out why you need to include this header file. Thanks, Jianfeng > > #define FDPOLLERR (POLLERR | POLLHUP | POLLNVAL) > > @@ -272,3 +273,51 @@ > > return NULL; > } > + > +static void > +fdset_pipe_read_cb(int readfd, void *dat __rte_unused, > + int *remove __rte_unused) > +{ > + char charbuf[16]; > + read(readfd, charbuf, sizeof(charbuf)); > +} > + > +void > +fdset_pipe_uninit(struct fdset *fdset) > +{ > + fdset_del(fdset, fdset->u.readfd); > + close(fdset->u.readfd); > + close(fdset->u.writefd); > +} > + > +int > +fdset_pipe_init(struct fdset *fdset) > +{ > + int ret; > + > + if (pipe(fdset->u.pipefd) < 0) { > + RTE_LOG(ERR, VHOST_CONFIG, > + "failed to create pipe for vhost fdset\n"); > + return -1; > + } > + > + ret = fdset_add(fdset, fdset->u.readfd, > + fdset_pipe_read_cb, NULL, NULL); > + > + if (ret < 0) { > + RTE_LOG(ERR, VHOST_CONFIG, > + "failed to add pipe readfd %d into vhost server > fdset\n", > + fdset->u.readfd); > + > + fdset_pipe_uninit(fdset); > + return -1; > + } > + > + return 0; > +} > + > +void > +fdset_pipe_notify(struct fdset *fdset) > +{ > + write(fdset->u.writefd, "1", 1); > +} > diff --git a/lib/librte_vhost/fd_man.h b/lib/librte_vhost/fd_man.h > index 3a9276c..76a42fb 100644 > --- a/lib/librte_vhost/fd_man.h > +++ b/lib/librte_vhost/fd_man.h > @@ -25,6 +25,16 @@ struct fdset { > struct fdentry fd[MAX_FDS]; > pthread_mutex_t fd_mutex; > int num; /* current fd number of this fdset */ > + > + union pipefds { > + struct { > + int pipefd[2]; > + }; > + struct { > + int readfd; > + int writefd; > + }; > + } u; > }; > > > @@ -37,4 +47,10 @@ int fdset_add(struct fdset *pfdset, int fd, > > void *fdset_event_dispatch(void *arg); > > +int fdset_pipe_init(struct fdset *fdset); > + > +void fdset_pipe_uninit(struct fdset *fdset); > + > +void fdset_pipe_notify(struct fdset *fdset); > + > #endif > diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c > index 95bed78..795239c 100644 > --- a/lib/librte_vhost/socket.c > +++ b/lib/librte_vhost/socket.c > @@ -231,6 +231,8 @@ struct vhost_user { > pthread_mutex_lock(&vsocket->conn_mutex); > TAILQ_INSERT_TAIL(&vsocket->conn_list, conn, next); > pthread_mutex_unlock(&vsocket->conn_mutex); > + > + fdset_pipe_notify(&vhost_user.fdset); > return; > > err: > @@ -829,11 +831,23 @@ struct vhost_device_ops const * > return -1; > > if (fdset_tid == 0) { > + /** > + * create a pipe which will be waited by poll and notified to > + * rebuild the wait list of poll. > + */ > + if (fdset_pipe_init(&vhost_user.fdset) < 0) { > + RTE_LOG(ERR, VHOST_CONFIG, > + "failed to create pipe for vhost fdset\n"); > + return -1; > + } > + > int ret = pthread_create(&fdset_tid, NULL, fdset_event_dispatch, > &vhost_user.fdset); > if (ret != 0) { > RTE_LOG(ERR, VHOST_CONFIG, > "failed to create fdset handling thread"); > + > + fdset_pipe_uninit(&vhost_user.fdset); > return -1; > } else { > snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN, > -- > 1.8.3.1
