On Sun, Dec 11, 2022 at 6:40 PM Jiachen Zhang <zhangjiachen.jaycee@xxxxxxxxxxxxx> wrote: > > Support virtio-fs multiple virtqueues and distribute requests across the > multiqueue complex automatically based on the IRQ affinity. > > This commit is based on Connor's patch in the virtio-fs mailing-list, > and additionally intergates cpu-to-vq map into struct virtio_fs so that > this virtio-fs multi-queue feature can fit into multiple virtio-fs mounts. > > Link: https://www.mail-archive.com/virtio-fs@xxxxxxxxxx/msg03320.html > Suggested-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > Cc: Connor Kuehl <ckuehl@xxxxxxxxxx> > Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@xxxxxxxxxxxxx> > --- Hi all, The corresponding QEMU virtiofsd changes can be found in the qemu-devel mailing list. The mail link is https://lore.kernel.org/qemu-devel/20221211104743.27333-1-zhangjiachen.jaycee@xxxxxxxxxxxxx/ . To enable this multi-queue feature with QEMU emulated virtio-fs devices, you should specify both the qemu-system-x86_64 vhost-user-fs parameter and the virtiofsd parameter. For example, to setup 16 virtio-fs request queues, you should apply the kernel patch in this mail, the QEMU vhost-user-fs device should be like '-device vhost-user-fs-pci,chardev=char0,tag=myfs,num-request-queues=16', and for the virtiofsd you should specify '-o num_request_queues=16'. Thanks, Jiachen > fs/fuse/virtio_fs.c | 37 +++++++++++++++++++++++++++++-------- > 1 file changed, 29 insertions(+), 8 deletions(-) > > diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c > index 4d8d4f16c727..410968dede0c 100644 > --- a/fs/fuse/virtio_fs.c > +++ b/fs/fuse/virtio_fs.c > @@ -32,8 +32,9 @@ static DEFINE_MUTEX(virtio_fs_mutex); > static LIST_HEAD(virtio_fs_instances); > > enum { > - VQ_HIPRIO, > - VQ_REQUEST > + VQ_HIPRIO = 0, > + /* TODO add VQ_NOTIFICATION according to the virtio 1.2 spec. */ > + VQ_REQUEST = 1, > }; > > #define VQ_NAME_LEN 24 > @@ -59,6 +60,7 @@ struct virtio_fs { > struct list_head list; /* on virtio_fs_instances */ > char *tag; > struct virtio_fs_vq *vqs; > + struct virtio_fs_vq * __percpu *vq_proxy; > unsigned int nvqs; /* number of virtqueues */ > unsigned int num_request_queues; /* number of request queues */ > struct dax_device *dax_dev; > @@ -686,6 +688,7 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev, > struct virtqueue **vqs; > vq_callback_t **callbacks; > const char **names; > + struct irq_affinity desc = { .pre_vectors = 1, .nr_sets = 1, }; > unsigned int i; > int ret = 0; > > @@ -694,11 +697,16 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev, > if (fs->num_request_queues == 0) > return -EINVAL; > > + fs->num_request_queues = min_t(unsigned int, nr_cpu_ids, > + fs->num_request_queues); > + > fs->nvqs = VQ_REQUEST + fs->num_request_queues; > fs->vqs = kcalloc(fs->nvqs, sizeof(fs->vqs[VQ_HIPRIO]), GFP_KERNEL); > if (!fs->vqs) > return -ENOMEM; > > + pr_debug("virtio-fs: number of vqs: %d\n", fs->nvqs); > + > vqs = kmalloc_array(fs->nvqs, sizeof(vqs[VQ_HIPRIO]), GFP_KERNEL); > callbacks = kmalloc_array(fs->nvqs, sizeof(callbacks[VQ_HIPRIO]), > GFP_KERNEL); > @@ -723,12 +731,26 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev, > names[i] = fs->vqs[i].name; > } > > - ret = virtio_find_vqs(vdev, fs->nvqs, vqs, callbacks, names, NULL); > + ret = virtio_find_vqs(vdev, fs->nvqs, vqs, callbacks, names, &desc); > if (ret < 0) > goto out; > > - for (i = 0; i < fs->nvqs; i++) > + fs->vq_proxy = alloc_percpu(struct virtio_fs_vq *); > + for (i = 0; i < fs->nvqs; i++) { > + const struct cpumask *mask; > + unsigned int cpu; > + > fs->vqs[i].vq = vqs[i]; > + if (i == VQ_HIPRIO) > + continue; > + > + mask = vdev->config->get_vq_affinity(vdev, i); > + for_each_cpu(cpu, mask) { > + struct virtio_fs_vq **cpu_vq = per_cpu_ptr(fs->vq_proxy, cpu); > + *cpu_vq = &fs->vqs[i]; > + pr_debug("virtio-fs: map cpu %d to vq%d\n", cpu, i); > + } > + } > > virtio_fs_start_all_queues(fs); > out: > @@ -875,8 +897,6 @@ static int virtio_fs_probe(struct virtio_device *vdev) > if (ret < 0) > goto out; > > - /* TODO vq affinity */ > - > ret = virtio_fs_setup_dax(vdev, fs); > if (ret < 0) > goto out_vqs; > @@ -926,6 +946,7 @@ static void virtio_fs_remove(struct virtio_device *vdev) > virtio_fs_stop_all_queues(fs); > virtio_fs_drain_all_queues_locked(fs); > virtio_reset_device(vdev); > + free_percpu(fs->vq_proxy); > virtio_fs_cleanup_vqs(vdev); > > vdev->priv = NULL; > @@ -1223,7 +1244,6 @@ static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, > static void virtio_fs_wake_pending_and_unlock(struct fuse_iqueue *fiq) > __releases(fiq->lock) > { > - unsigned int queue_id = VQ_REQUEST; /* TODO multiqueue */ > struct virtio_fs *fs; > struct fuse_req *req; > struct virtio_fs_vq *fsvq; > @@ -1243,7 +1263,8 @@ __releases(fiq->lock) > req->in.h.nodeid, req->in.h.len, > fuse_len_args(req->args->out_numargs, req->args->out_args)); > > - fsvq = &fs->vqs[queue_id]; > + fsvq = this_cpu_read(*fs->vq_proxy); > + > ret = virtio_fs_enqueue_req(fsvq, req, false); > if (ret < 0) { > if (ret == -ENOMEM || ret == -ENOSPC) { > -- > 2.20.1 >
