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| author | Fam Zheng <famz@redhat.com> | 2017-02-09 16:40:47 +0800 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2017-02-17 21:52:30 +0200 |
| commit | 0793169870f376bc9959b7d81df48ab4a90dcceb (patch) | |
| tree | 706cd7d990534f97bcf1dd9ca8ca09c4e7d350ff /hw/block | |
| parent | 4bb571d857d973d9308d9fdb1f48d983d6639bd4 (diff) | |
| download | qemu-0793169870f376bc9959b7d81df48ab4a90dcceb.zip qemu-0793169870f376bc9959b7d81df48ab4a90dcceb.tar.gz qemu-0793169870f376bc9959b7d81df48ab4a90dcceb.tar.bz2 | |
virtio: Report real progress in VQ aio poll handler
In virtio_queue_host_notifier_aio_poll, not all "!virtio_queue_empty()"
cases are making true progress.
Currently the offending one is virtio-scsi event queue, whose handler
does nothing if no event is pending. As a result aio_poll() will spin on
the "non-empty" VQ and take 100% host CPU.
Fix this by reporting actual progress from virtio queue aio handlers.
Reported-by: Ed Swierk <eswierk@skyportsystems.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Tested-by: Ed Swierk <eswierk@skyportsystems.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/block')
| -rw-r--r-- | hw/block/dataplane/virtio-blk.c | 4 | ||||
| -rw-r--r-- | hw/block/virtio-blk.c | 12 |
2 files changed, 12 insertions, 4 deletions
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index d1f9f63..5556f0e 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -147,7 +147,7 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s) g_free(s); } -static void virtio_blk_data_plane_handle_output(VirtIODevice *vdev, +static bool virtio_blk_data_plane_handle_output(VirtIODevice *vdev, VirtQueue *vq) { VirtIOBlock *s = (VirtIOBlock *)vdev; @@ -155,7 +155,7 @@ static void virtio_blk_data_plane_handle_output(VirtIODevice *vdev, assert(s->dataplane); assert(s->dataplane_started); - virtio_blk_handle_vq(s, vq); + return virtio_blk_handle_vq(s, vq); } /* Context: QEMU global mutex held */ diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 702eda8..baaa195 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -581,10 +581,11 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) return 0; } -void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq) +bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq) { VirtIOBlockReq *req; MultiReqBuffer mrb = {}; + bool progress = false; blk_io_plug(s->blk); @@ -592,6 +593,7 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq) virtio_queue_set_notification(vq, 0); while ((req = virtio_blk_get_request(s, vq))) { + progress = true; if (virtio_blk_handle_request(req, &mrb)) { virtqueue_detach_element(req->vq, &req->elem, 0); virtio_blk_free_request(req); @@ -607,6 +609,12 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq) } blk_io_unplug(s->blk); + return progress; +} + +static void virtio_blk_handle_output_do(VirtIOBlock *s, VirtQueue *vq) +{ + virtio_blk_handle_vq(s, vq); } static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) @@ -622,7 +630,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) return; } } - virtio_blk_handle_vq(s, vq); + virtio_blk_handle_output_do(s, vq); } static void virtio_blk_dma_restart_bh(void *opaque) |