From: Longpeng Date: Tue, 27 Dec 2022 07:20:15 +0000 (+0800) Subject: vdpa: commit all host notifier MRs in a single MR transaction X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e66f2311d680de28e1cd95570822c4e17841120d;p=qemu.git vdpa: commit all host notifier MRs in a single MR transaction This allows the vhost-vdpa device to batch the setup of all its MRs of host notifiers. This significantly reduces the device starting time, e.g. the time spend on setup the host notifier MRs reduce from 423ms to 32ms for a VM with 64 vCPUs and 3 vhost-vDPA generic devices (vdpa_sim_blk, 64vq per device). Signed-off-by: Longpeng Message-Id: <20221227072015.3134-4-longpeng2@huawei.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Philippe Mathieu-Daudé --- diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index c295a8c917..542e003101 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -519,9 +519,18 @@ static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n) { int i; + /* + * Pack all the changes to the memory regions in a single + * transaction to avoid a few updating of the address space + * topology. + */ + memory_region_transaction_begin(); + for (i = dev->vq_index; i < dev->vq_index + n; i++) { vhost_vdpa_host_notifier_uninit(dev, i); } + + memory_region_transaction_commit(); } static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev) @@ -534,17 +543,21 @@ static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev) return; } + /* + * Pack all the changes to the memory regions in a single + * transaction to avoid a few updating of the address space + * topology. + */ + memory_region_transaction_begin(); + for (i = dev->vq_index; i < dev->vq_index + dev->nvqs; i++) { if (vhost_vdpa_host_notifier_init(dev, i)) { - goto err; + vhost_vdpa_host_notifiers_uninit(dev, i - dev->vq_index); + break; } } - return; - -err: - vhost_vdpa_host_notifiers_uninit(dev, i - dev->vq_index); - return; + memory_region_transaction_commit(); } static void vhost_vdpa_svq_cleanup(struct vhost_dev *dev)