On Sun, 2011-12-04 at 20:23 +0200, Sasha Levin wrote: [snip] Rusty, Michael, does the below looks a reasonable optimization for you? should I send it as a patch? > Something like the following patch: > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index c7a2c20..3166ca0 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -82,6 +82,7 @@ struct vring_virtqueue > > /* Host supports indirect buffers */ > bool indirect; > + struct kmem_cache *indirect_cache; > > /* Host publishes avail event idx */ > bool event; > @@ -110,6 +111,9 @@ struct vring_virtqueue > > #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) > > +static unsigned int ind_alloc_thresh = 0; > +module_param(ind_alloc_thresh, uint, S_IRUGO); > + > /* Set up an indirect table of descriptors and add it to the queue. */ > static int vring_add_indirect(struct vring_virtqueue *vq, > struct scatterlist sg[], > @@ -121,7 +125,10 @@ static int vring_add_indirect(struct vring_virtqueue *vq, > unsigned head; > int i; > > - desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > + if ((out + in) <= ind_alloc_thresh) > + desc = kmem_cache_alloc(vq->indirect_cache, gfp); > + else > + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > if (!desc) > return -ENOMEM; > > @@ -479,6 +486,9 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, > vq->broken = false; > vq->last_used_idx = 0; > vq->num_added = 0; > + if (ind_alloc_thresh) > + vq->indirect_cache = KMEM_CACHE(vring_desc[ind_alloc_thresh], 0); > list_add_tail(&vq->vq.list, &vdev->vqs); > #ifdef DEBUG > vq->in_use = false; > -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
