From: Vivek Goyal <vgoyal@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com,
Stefan Hajnoczi <stefanha@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
chirantan@chromium.org,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 1/5] virtiofs: Do not end request in submission context
Date: Mon, 21 Oct 2019 07:52:24 -0400 [thread overview]
Message-ID: <20191021115224.GA13573@redhat.com> (raw)
In-Reply-To: <CAJfpegtrFvuBUuQ7B+ynCLVmgZ8zRjbUYZYg+BzG6HDmt5RyXw@mail.gmail.com>
On Mon, Oct 21, 2019 at 10:03:39AM +0200, Miklos Szeredi wrote:
[..]
> > static void virtio_fs_hiprio_dispatch_work(struct work_struct *work)
> > @@ -502,6 +522,7 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev,
> > names[VQ_HIPRIO] = fs->vqs[VQ_HIPRIO].name;
> > INIT_WORK(&fs->vqs[VQ_HIPRIO].done_work, virtio_fs_hiprio_done_work);
> > INIT_LIST_HEAD(&fs->vqs[VQ_HIPRIO].queued_reqs);
> > + INIT_LIST_HEAD(&fs->vqs[VQ_HIPRIO].end_reqs);
> > INIT_DELAYED_WORK(&fs->vqs[VQ_HIPRIO].dispatch_work,
> > virtio_fs_hiprio_dispatch_work);
> > spin_lock_init(&fs->vqs[VQ_HIPRIO].lock);
> > @@ -511,8 +532,9 @@ static int virtio_fs_setup_vqs(struct virtio_device *vdev,
> > spin_lock_init(&fs->vqs[i].lock);
> > INIT_WORK(&fs->vqs[i].done_work, virtio_fs_requests_done_work);
> > INIT_DELAYED_WORK(&fs->vqs[i].dispatch_work,
> > - virtio_fs_dummy_dispatch_work);
> > + virtio_fs_request_dispatch_work);
> > INIT_LIST_HEAD(&fs->vqs[i].queued_reqs);
> > + INIT_LIST_HEAD(&fs->vqs[i].end_reqs);
> > snprintf(fs->vqs[i].name, sizeof(fs->vqs[i].name),
> > "requests.%u", i - VQ_REQUEST);
> > callbacks[i] = virtio_fs_vq_done;
> > @@ -918,6 +940,7 @@ __releases(fiq->lock)
> > struct fuse_conn *fc;
> > struct fuse_req *req;
> > struct fuse_pqueue *fpq;
> > + struct virtio_fs_vq *fsvq;
> > int ret;
> >
> > WARN_ON(list_empty(&fiq->pending));
> > @@ -951,7 +974,8 @@ __releases(fiq->lock)
> > smp_mb__after_atomic();
> >
> > retry:
> > - ret = virtio_fs_enqueue_req(&fs->vqs[queue_id], req);
> > + fsvq = &fs->vqs[queue_id];
> > + ret = virtio_fs_enqueue_req(fsvq, req);
> > if (ret < 0) {
> > if (ret == -ENOMEM || ret == -ENOSPC) {
> > /* Virtqueue full. Retry submission */
> > @@ -965,7 +989,13 @@ __releases(fiq->lock)
> > clear_bit(FR_SENT, &req->flags);
> > list_del_init(&req->list);
> > spin_unlock(&fpq->lock);
> > - fuse_request_end(fc, req);
> > +
> > + /* Can't end request in submission context. Use a worker */
> > + spin_lock(&fsvq->lock);
> > + list_add_tail(&req->list, &fsvq->end_reqs);
> > + schedule_delayed_work(&fsvq->dispatch_work,
> > + msecs_to_jiffies(1));
>
> What's the reason to delay by one msec? If this is purely for
> deadlock avoidance, then a zero delay would work better, no?
Hi Miklos,
I have no good reason to do that. Will change it to zero delay.
Thanks
Vivek
next prev parent reply other threads:[~2019-10-21 11:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-15 17:46 [PATCH 0/5] virtiofs: Fix couple of deadlocks Vivek Goyal
2019-10-15 17:46 ` [PATCH 1/5] virtiofs: Do not end request in submission context Vivek Goyal
2019-10-21 8:03 ` Miklos Szeredi
2019-10-21 11:52 ` Vivek Goyal [this message]
2019-10-21 13:58 ` Miklos Szeredi
2019-10-15 17:46 ` [PATCH 2/5] virtiofs: No need to check fpq->connected state Vivek Goyal
2019-10-15 17:46 ` [PATCH 3/5] virtiofs: Set FR_SENT flag only after request has been sent Vivek Goyal
2019-10-15 17:46 ` [PATCH 4/5] virtiofs: Count pending forgets as in_flight forgets Vivek Goyal
2019-10-15 17:46 ` [PATCH 5/5] virtiofs: Retry request submission from worker context Vivek Goyal
2019-10-21 8:15 ` Miklos Szeredi
2019-10-21 13:01 ` Vivek Goyal
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