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[for-6.1 4/4] virtio-scsi: Configure all host notifiers in a single MR t
From: |
Greg Kurz |
Subject: |
[for-6.1 4/4] virtio-scsi: Configure all host notifiers in a single MR transaction |
Date: |
Wed, 7 Apr 2021 16:35:01 +0200 |
This allows the virtio-scsi-pci device to batch the setup of all its
host notifiers. This significantly improves boot time of VMs with a
high number of vCPUs, e.g. from 6m5.563s down to 1m2.884s for a
pseries machine with 384 vCPUs.
Note that memory_region_transaction_commit() must be called before
virtio_bus_cleanup_host_notifier() because the latter might close
ioeventfds that the transaction still assumes to be around when it
commits.
Signed-off-by: Greg Kurz <groug@kaod.org>
---
hw/scsi/virtio-scsi-dataplane.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index b2cb3d9dcc64..28e003250a11 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -152,6 +152,8 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
goto fail_guest_notifiers;
}
+ memory_region_transaction_begin();
+
rc = virtio_scsi_set_host_notifier(s, vs->ctrl_vq, 0);
if (rc != 0) {
goto fail_host_notifiers;
@@ -173,6 +175,8 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
vq_init_count++;
}
+ memory_region_transaction_commit();
+
aio_context_acquire(s->ctx);
virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx,
virtio_scsi_data_plane_handle_ctrl);
@@ -192,6 +196,11 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
fail_host_notifiers:
for (i = 0; i < vq_init_count; i++) {
virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false);
+ }
+
+ memory_region_transaction_commit();
+
+ for (i = 0; i < vq_init_count; i++) {
virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
}
k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false);
@@ -229,8 +238,15 @@ void virtio_scsi_dataplane_stop(VirtIODevice *vdev)
blk_drain_all(); /* ensure there are no in-flight requests */
+ memory_region_transaction_begin();
+
for (i = 0; i < vs->conf.num_queues + 2; i++) {
virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false);
+ }
+
+ memory_region_transaction_commit();
+
+ for (i = 0; i < vs->conf.num_queues + 2; i++) {
virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
}
--
2.26.3
- [for-6.1 0/4] virtio: Improve boot time of virtio-scsi-pci and virtio-blk-pci, Greg Kurz, 2021/04/07
- [for-6.1 1/4] virtio-blk: Fix rollback path in virtio_blk_data_plane_start(), Greg Kurz, 2021/04/07
- [for-6.1 2/4] virtio-blk: Configure all host notifiers in a single MR transaction, Greg Kurz, 2021/04/07
- [for-6.1 3/4] virtio-scsi: Set host notifiers and callbacks separately, Greg Kurz, 2021/04/07
- [for-6.1 4/4] virtio-scsi: Configure all host notifiers in a single MR transaction,
Greg Kurz <=
- Re: [for-6.1 0/4] virtio: Improve boot time of virtio-scsi-pci and virtio-blk-pci, Greg Kurz, 2021/04/19
- Re: [for-6.1 0/4] virtio: Improve boot time of virtio-scsi-pci and virtio-blk-pci, Michael S. Tsirkin, 2021/04/19