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e6db5df7e2
With the introduction of the batch hinting, meaningless batches can be
created with no IOTLB updates if the memory region was skipped by
vhost_vdpa_listener_skipped_section. This is the case of host notifiers
memory regions, device un/realize, and others. This causes the vdpa
device to receive dma mapping settings with no changes, a possibly
expensive operation for nothing.
To avoid that, VHOST_IOTLB_BATCH_BEGIN hint is delayed until we have a
meaningful (not skipped section) mapping or unmapping operation, and
VHOST_IOTLB_BATCH_END is not written unless at least one of _UPDATE /
_INVALIDATE has been issued.
v3:
* Use a bool instead of a counter avoiding potential number wrapping
* Fix bad check on _commit
* Move VHOST_BACKEND_F_IOTLB_BATCH check to
vhost_vdpa_iotlb_batch_begin_once
v2 (from RFC):
* Rename misleading name
* Abstract start batching function for listener_add/del
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20210812140933.226288-1-eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| .. | ||
| vhost-backend.h | ||
| vhost-scsi-common.h | ||
| vhost-scsi.h | ||
| vhost-user-blk.h | ||
| vhost-user-fs.h | ||
| vhost-user-i2c.h | ||
| vhost-user-scsi.h | ||
| vhost-user-vsock.h | ||
| vhost-user.h | ||
| vhost-vdpa.h | ||
| vhost-vsock-common.h | ||
| vhost-vsock.h | ||
| vhost.h | ||
| virtio-access.h | ||
| virtio-balloon.h | ||
| virtio-blk.h | ||
| virtio-bus.h | ||
| virtio-crypto.h | ||
| virtio-gpu-bswap.h | ||
| virtio-gpu-pci.h | ||
| virtio-gpu-pixman.h | ||
| virtio-gpu.h | ||
| virtio-input.h | ||
| virtio-iommu.h | ||
| virtio-mem.h | ||
| virtio-mmio.h | ||
| virtio-net.h | ||
| virtio-pmem.h | ||
| virtio-rng.h | ||
| virtio-scsi.h | ||
| virtio-serial.h | ||
| virtio.h | ||