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authorPaolo Bonzini <pbonzini@redhat.com>2015-08-21 15:53:55 -0700
committerMichael S. Tsirkin <mst@redhat.com>2015-09-08 13:29:14 +0300
commit53eab6fd2777dc7cb338519827e23f8bf892903e (patch)
tree29fc9d97ab032f82cd49bad8737cd4c6d0ad223c /drivers/block/virtio_blk.c
parent64291f7db5bd8150a74ad2036f1037e6a0428df2 (diff)
virtio-blk: use VIRTIO_BLK_F_WCE and VIRTIO_BLK_F_CONFIG_WCE in virtio1
VIRTIO_BLK_F_CONFIG_WCE is important in order to achieve good performance (up to 2x, though more realistically +30-40%) in latency-bound workloads. However, it was removed by mistake together with VIRTIO_BLK_F_FLUSH. It will be restored in the next revision of the virtio 1.0 standard, so do the same in Linux. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/block/virtio_blk.c')
-rw-r--r--drivers/block/virtio_blk.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index d4d05f064d39..ea2c17c66dfb 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -478,8 +478,7 @@ static int virtblk_get_cache_mode(struct virtio_device *vdev)
struct virtio_blk_config, wce,
&writeback);
if (err)
- writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
- virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
+ writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
return writeback;
}
@@ -840,7 +839,7 @@ static unsigned int features_legacy[] = {
static unsigned int features[] = {
VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
- VIRTIO_BLK_F_TOPOLOGY,
+ VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_MQ,
};