From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Wang Subject: [PATCH v1 1/2] virtio-balloon: tweak config_changed implementation Date: Thu, 3 Jan 2019 13:31:01 +0800 Message-ID: <1546493462-32244-2-git-send-email-wei.w.wang@intel.com> References: <1546493462-32244-1-git-send-email-wei.w.wang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1546493462-32244-1-git-send-email-wei.w.wang@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com Cc: pasic@linux.ibm.com, dgilbert@redhat.com, pbonzini@redhat.com List-Id: virtualization@lists.linuxfoundation.org virtio-ccw has deadlock issues with reading config registers inside the interrupt context, so we tweak the virtballoon_changed implementation by moving the config read operations into the related workqueue contexts. Signed-off-by: Wei Wang --- drivers/virtio/virtio_balloon.c | 54 ++++++++++++++++++++--------------------- 1 file changed, 26 insertions(+), 28 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 728ecd1..9a82a11 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -394,33 +394,15 @@ static void virtballoon_changed(struct virtio_device *vdev) { struct virtio_balloon *vb = vdev->priv; unsigned long flags; - s64 diff = towards_target(vb); - - if (diff) { - spin_lock_irqsave(&vb->stop_update_lock, flags); - if (!vb->stop_update) - queue_work(system_freezable_wq, - &vb->update_balloon_size_work); - spin_unlock_irqrestore(&vb->stop_update_lock, flags); - } - if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { - virtio_cread(vdev, struct virtio_balloon_config, - free_page_report_cmd_id, &vb->cmd_id_received); - if (vb->cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { - /* Pass ULONG_MAX to give back all the free pages */ - return_free_pages_to_mm(vb, ULONG_MAX); - } else if (vb->cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && - vb->cmd_id_received != - virtio32_to_cpu(vdev, vb->cmd_id_active)) { - spin_lock_irqsave(&vb->stop_update_lock, flags); - if (!vb->stop_update) { - queue_work(vb->balloon_wq, - &vb->report_free_page_work); - } - spin_unlock_irqrestore(&vb->stop_update_lock, flags); - } + spin_lock_irqsave(&vb->stop_update_lock, flags); + if (!vb->stop_update) { + queue_work(system_freezable_wq, + &vb->update_balloon_size_work); + if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) + queue_work(vb->balloon_wq, &vb->report_free_page_work); } + spin_unlock_irqrestore(&vb->stop_update_lock, flags); } static void update_balloon_size(struct virtio_balloon *vb) @@ -637,11 +619,9 @@ static int send_free_pages(struct virtio_balloon *vb) return 0; } -static void report_free_page_func(struct work_struct *work) +static void virtio_balloon_report_free_page(struct virtio_balloon *vb) { int err; - struct virtio_balloon *vb = container_of(work, struct virtio_balloon, - report_free_page_work); struct device *dev = &vb->vdev->dev; /* Start by sending the received cmd id to host with an outbuf. */ @@ -659,6 +639,24 @@ static void report_free_page_func(struct work_struct *work) dev_err(dev, "Failed to send a stop id, err = %d\n", err); } +static void report_free_page_func(struct work_struct *work) +{ + struct virtio_balloon *vb = container_of(work, struct virtio_balloon, + report_free_page_work); + + virtio_cread(vb->vdev, struct virtio_balloon_config, + free_page_report_cmd_id, &vb->cmd_id_received); + + if (vb->cmd_id_received == VIRTIO_BALLOON_CMD_ID_DONE) { + /* Pass ULONG_MAX to give back all the free pages */ + return_free_pages_to_mm(vb, ULONG_MAX); + } else if (vb->cmd_id_received != VIRTIO_BALLOON_CMD_ID_STOP && + vb->cmd_id_received != + virtio32_to_cpu(vb->vdev, vb->cmd_id_active)) { + virtio_balloon_report_free_page(vb); + } +} + #ifdef CONFIG_BALLOON_COMPACTION /* * virtballoon_migratepage - perform the balloon page migration on behalf of -- 2.7.4