Hi Miklos, Here are few small cleanups for virtiofs for 5.5. I had received some comments from Michael Tsirkin on original virtiofs patches and these cleanups are result of these comments. Thanks Vivek Vivek Goyal (3): virtiofs: Use a common function to send forget virtiofs: Do not send forget request "struct list_head" element virtiofs: Use completions while waiting for queue to be drained fs/fuse/virtio_fs.c | 204 ++++++++++++++++++++++---------------------- 1 file changed, 103 insertions(+), 101 deletions(-) -- 2.20.1
Vivek Goyal
2019-Oct-30 15:07 UTC
[PATCH 1/3] virtiofs: Use a common function to send forget
Currently we are duplicating logic to send forgets at two places. Consolidate the code by calling one helper function. This also uses virtqueue_add_outbuf() instead of virtqueue_add_sgs(). Former is simpler to call. Signed-off-by: Vivek Goyal <vgoyal at redhat.com> --- fs/fuse/virtio_fs.c | 150 +++++++++++++++++++------------------------- 1 file changed, 63 insertions(+), 87 deletions(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index a5c86048b96e..6cc7be170cb8 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -313,17 +313,71 @@ static void virtio_fs_request_dispatch_work(struct work_struct *work) } } +/* + * Returns 1 if queue is full and sender should wait a bit before sending + * next request, 0 otherwise. + */ +static int send_forget_request(struct virtio_fs_vq *fsvq, + struct virtio_fs_forget *forget, + bool in_flight) +{ + struct scatterlist sg; + struct virtqueue *vq; + int ret = 0; + bool notify; + + spin_lock(&fsvq->lock); + if (!fsvq->connected) { + if (in_flight) + dec_in_flight_req(fsvq); + kfree(forget); + goto out; + } + + sg_init_one(&sg, forget, sizeof(*forget)); + vq = fsvq->vq; + dev_dbg(&vq->vdev->dev, "%s\n", __func__); + + ret = virtqueue_add_outbuf(vq, &sg, 1, forget, GFP_ATOMIC); + if (ret < 0) { + if (ret == -ENOMEM || ret == -ENOSPC) { + pr_debug("virtio-fs: Could not queue FORGET: err=%d." + " Will try later\n", ret); + list_add_tail(&forget->list, &fsvq->queued_reqs); + schedule_delayed_work(&fsvq->dispatch_work, + msecs_to_jiffies(1)); + if (!in_flight) + inc_in_flight_req(fsvq); + /* Queue is full */ + ret = 1; + } else { + pr_debug("virtio-fs: Could not queue FORGET: err=%d." + " Dropping it.\n", ret); + kfree(forget); + if (in_flight) + dec_in_flight_req(fsvq); + } + goto out; + } + + if (!in_flight) + inc_in_flight_req(fsvq); + notify = virtqueue_kick_prepare(vq); + spin_unlock(&fsvq->lock); + + if (notify) + virtqueue_notify(vq); + return ret; +out: + spin_unlock(&fsvq->lock); + return ret; +} + static void virtio_fs_hiprio_dispatch_work(struct work_struct *work) { struct virtio_fs_forget *forget; struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq, dispatch_work.work); - struct virtqueue *vq = fsvq->vq; - struct scatterlist sg; - struct scatterlist *sgs[] = {&sg}; - bool notify; - int ret; - pr_debug("virtio-fs: worker %s called.\n", __func__); while (1) { spin_lock(&fsvq->lock); @@ -335,43 +389,9 @@ static void virtio_fs_hiprio_dispatch_work(struct work_struct *work) } list_del(&forget->list); - if (!fsvq->connected) { - dec_in_flight_req(fsvq); - spin_unlock(&fsvq->lock); - kfree(forget); - continue; - } - - sg_init_one(&sg, forget, sizeof(*forget)); - - /* Enqueue the request */ - dev_dbg(&vq->vdev->dev, "%s\n", __func__); - ret = virtqueue_add_sgs(vq, sgs, 1, 0, forget, GFP_ATOMIC); - if (ret < 0) { - if (ret == -ENOMEM || ret == -ENOSPC) { - pr_debug("virtio-fs: Could not queue FORGET: err=%d. Will try later\n", - ret); - list_add_tail(&forget->list, - &fsvq->queued_reqs); - schedule_delayed_work(&fsvq->dispatch_work, - msecs_to_jiffies(1)); - } else { - pr_debug("virtio-fs: Could not queue FORGET: err=%d. Dropping it.\n", - ret); - dec_in_flight_req(fsvq); - kfree(forget); - } - spin_unlock(&fsvq->lock); - return; - } - - notify = virtqueue_kick_prepare(vq); spin_unlock(&fsvq->lock); - - if (notify) - virtqueue_notify(vq); - pr_debug("virtio-fs: worker %s dispatched one forget request.\n", - __func__); + if (send_forget_request(fsvq, forget, true)) + return; } } @@ -710,14 +730,9 @@ __releases(fiq->lock) { struct fuse_forget_link *link; struct virtio_fs_forget *forget; - struct scatterlist sg; - struct scatterlist *sgs[] = {&sg}; struct virtio_fs *fs; - struct virtqueue *vq; struct virtio_fs_vq *fsvq; - bool notify; u64 unique; - int ret; link = fuse_dequeue_forget(fiq, 1, NULL); unique = fuse_get_unique(fiq); @@ -739,46 +754,7 @@ __releases(fiq->lock) .nlookup = link->forget_one.nlookup, }; - sg_init_one(&sg, forget, sizeof(*forget)); - - /* Enqueue the request */ - spin_lock(&fsvq->lock); - - if (!fsvq->connected) { - kfree(forget); - spin_unlock(&fsvq->lock); - goto out; - } - - vq = fsvq->vq; - dev_dbg(&vq->vdev->dev, "%s\n", __func__); - - ret = virtqueue_add_sgs(vq, sgs, 1, 0, forget, GFP_ATOMIC); - if (ret < 0) { - if (ret == -ENOMEM || ret == -ENOSPC) { - pr_debug("virtio-fs: Could not queue FORGET: err=%d. Will try later.\n", - ret); - list_add_tail(&forget->list, &fsvq->queued_reqs); - schedule_delayed_work(&fsvq->dispatch_work, - msecs_to_jiffies(1)); - inc_in_flight_req(fsvq); - } else { - pr_debug("virtio-fs: Could not queue FORGET: err=%d. Dropping it.\n", - ret); - kfree(forget); - } - spin_unlock(&fsvq->lock); - goto out; - } - - inc_in_flight_req(fsvq); - notify = virtqueue_kick_prepare(vq); - - spin_unlock(&fsvq->lock); - - if (notify) - virtqueue_notify(vq); -out: + send_forget_request(fsvq, forget, false); kfree(link); } -- 2.20.1
Vivek Goyal
2019-Oct-30 15:07 UTC
[PATCH 2/3] virtiofs: Do not send forget request "struct list_head" element
We are sending whole of virtio_fs_foreget struct to the other end over virtqueue. Other end does not need to see elements like "struct list". That's internal detail of guest kernel. Fix it. Signed-off-by: Vivek Goyal <vgoyal at redhat.com> --- fs/fuse/virtio_fs.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 6cc7be170cb8..43224db8d9ed 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -48,11 +48,15 @@ struct virtio_fs { unsigned int num_request_queues; /* number of request queues */ }; -struct virtio_fs_forget { +struct virtio_fs_forget_req { struct fuse_in_header ih; struct fuse_forget_in arg; +}; + +struct virtio_fs_forget { /* This request can be temporarily queued on virt queue */ struct list_head list; + struct virtio_fs_forget_req req; }; static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, @@ -325,6 +329,7 @@ static int send_forget_request(struct virtio_fs_vq *fsvq, struct virtqueue *vq; int ret = 0; bool notify; + struct virtio_fs_forget_req *req = &forget->req; spin_lock(&fsvq->lock); if (!fsvq->connected) { @@ -334,7 +339,7 @@ static int send_forget_request(struct virtio_fs_vq *fsvq, goto out; } - sg_init_one(&sg, forget, sizeof(*forget)); + sg_init_one(&sg, req, sizeof(*req)); vq = fsvq->vq; dev_dbg(&vq->vdev->dev, "%s\n", __func__); @@ -730,6 +735,7 @@ __releases(fiq->lock) { struct fuse_forget_link *link; struct virtio_fs_forget *forget; + struct virtio_fs_forget_req *req; struct virtio_fs *fs; struct virtio_fs_vq *fsvq; u64 unique; @@ -743,14 +749,15 @@ __releases(fiq->lock) /* Allocate a buffer for the request */ forget = kmalloc(sizeof(*forget), GFP_NOFS | __GFP_NOFAIL); + req = &forget->req; - forget->ih = (struct fuse_in_header){ + req->ih = (struct fuse_in_header){ .opcode = FUSE_FORGET, .nodeid = link->forget_one.nodeid, .unique = unique, - .len = sizeof(*forget), + .len = sizeof(*req), }; - forget->arg = (struct fuse_forget_in){ + req->arg = (struct fuse_forget_in){ .nlookup = link->forget_one.nlookup, }; -- 2.20.1
Vivek Goyal
2019-Oct-30 15:07 UTC
[PATCH 3/3] virtiofs: Use completions while waiting for queue to be drained
While we wait for queue to finish draining, use completions instead of uslee_range(). This is better way of waiting for event. Signed-off-by: Vivek Goyal <vgoyal at redhat.com> --- fs/fuse/virtio_fs.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 43224db8d9ed..b5ba83ef1914 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -35,6 +35,7 @@ struct virtio_fs_vq { struct fuse_dev *fud; bool connected; long in_flight; + struct completion in_flight_zero; /* No inflight requests */ char name[24]; } ____cacheline_aligned_in_smp; @@ -85,6 +86,8 @@ static inline void dec_in_flight_req(struct virtio_fs_vq *fsvq) { WARN_ON(fsvq->in_flight <= 0); fsvq->in_flight--; + if (!fsvq->in_flight) + complete(&fsvq->in_flight_zero); } static void release_virtio_fs_obj(struct kref *ref) @@ -115,22 +118,23 @@ static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq) WARN_ON(fsvq->in_flight < 0); /* Wait for in flight requests to finish.*/ - while (1) { - spin_lock(&fsvq->lock); - if (!fsvq->in_flight) { - spin_unlock(&fsvq->lock); - break; - } + spin_lock(&fsvq->lock); + if (fsvq->in_flight) { + /* We are holding virtio_fs_mutex. There should not be any + * waiters waiting for completion. + */ + reinit_completion(&fsvq->in_flight_zero); + spin_unlock(&fsvq->lock); + wait_for_completion(&fsvq->in_flight_zero); + } else { spin_unlock(&fsvq->lock); - /* TODO use completion instead of timeout */ - usleep_range(1000, 2000); } flush_work(&fsvq->done_work); flush_delayed_work(&fsvq->dispatch_work); } -static void virtio_fs_drain_all_queues(struct virtio_fs *fs) +static void virtio_fs_drain_all_queues_locked(struct virtio_fs *fs) { struct virtio_fs_vq *fsvq; int i; @@ -141,6 +145,19 @@ static void virtio_fs_drain_all_queues(struct virtio_fs *fs) } } +static void virtio_fs_drain_all_queues(struct virtio_fs *fs) +{ + /* Provides mutual exclusion between ->remove and ->kill_sb + * paths. We don't want both of these draining queue at the + * same time. Current completion logic reinits completion + * and that means there should not be any other thread + * doing reinit or waiting for completion already. + */ + mutex_lock(&virtio_fs_mutex); + virtio_fs_drain_all_queues_locked(fs); + mutex_unlock(&virtio_fs_mutex); +} + static void virtio_fs_start_all_queues(struct virtio_fs *fs) { struct virtio_fs_vq *fsvq; @@ -581,6 +598,7 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev, INIT_LIST_HEAD(&fs->vqs[VQ_HIPRIO].end_reqs); INIT_DELAYED_WORK(&fs->vqs[VQ_HIPRIO].dispatch_work, virtio_fs_hiprio_dispatch_work); + init_completion(&fs->vqs[VQ_HIPRIO].in_flight_zero); spin_lock_init(&fs->vqs[VQ_HIPRIO].lock); /* Initialize the requests virtqueues */ @@ -591,6 +609,7 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev, virtio_fs_request_dispatch_work); INIT_LIST_HEAD(&fs->vqs[i].queued_reqs); INIT_LIST_HEAD(&fs->vqs[i].end_reqs); + init_completion(&fs->vqs[i].in_flight_zero); snprintf(fs->vqs[i].name, sizeof(fs->vqs[i].name), "requests.%u", i - VQ_REQUEST); callbacks[i] = virtio_fs_vq_done; @@ -684,7 +703,7 @@ static void virtio_fs_remove(struct virtio_device *vdev) /* This device is going away. No one should get new reference */ list_del_init(&fs->list); virtio_fs_stop_all_queues(fs); - virtio_fs_drain_all_queues(fs); + virtio_fs_drain_all_queues_locked(fs); vdev->config->reset(vdev); virtio_fs_cleanup_vqs(vdev, fs); -- 2.20.1
Stefan Hajnoczi
2019-Nov-13 14:30 UTC
[PATCH 2/3] virtiofs: Do not send forget request "struct list_head" element
On Wed, Oct 30, 2019 at 11:07:18AM -0400, Vivek Goyal wrote:> We are sending whole of virtio_fs_foreget struct to the other end overs/foreget/forget/ -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20191113/274e7775/attachment.sig>
Stefan Hajnoczi
2019-Nov-13 14:40 UTC
[PATCH 3/3] virtiofs: Use completions while waiting for queue to be drained
On Wed, Oct 30, 2019 at 11:07:19AM -0400, Vivek Goyal wrote:> While we wait for queue to finish draining, use completions instead of > uslee_range(). This is better way of waiting for event.s/uslee_range()/usleep_range()/ -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20191113/b18e28ad/attachment.sig>
On Wed, Oct 30, 2019 at 11:07:16AM -0400, Vivek Goyal wrote:> Hi Miklos, > > Here are few small cleanups for virtiofs for 5.5. I had received some > comments from Michael Tsirkin on original virtiofs patches and these > cleanups are result of these comments. > > Thanks > Vivek > > Vivek Goyal (3): > virtiofs: Use a common function to send forget > virtiofs: Do not send forget request "struct list_head" element > virtiofs: Use completions while waiting for queue to be drained > > fs/fuse/virtio_fs.c | 204 ++++++++++++++++++++++---------------------- > 1 file changed, 103 insertions(+), 101 deletions(-) > > -- > 2.20.1 >There are typos in the commit descriptions but the code looks fine: Reviewed-by: Stefan Hajnoczi <stefanha at redhat.com> -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 488 bytes Desc: not available URL: <http://lists.linuxfoundation.org/pipermail/virtualization/attachments/20191113/26efed48/attachment.sig>
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