Re: [Qemu-devel] [PATCH 1/5] virtiofsd: skip unnecessary vu_queue_get_avail_bytes()

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Stefan Hajnoczi (stefanha@redhat.com) wrote:
> When debug output is disabled there is no need to calculate the number
> of in/out bytes available.
> 
> There is also no need to skip a request if there are 0 out bytes.  The
> request parsing code already handles invalid requests.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Thanks, I've squashed this in to existing commits.

Dave

> ---
>  contrib/virtiofsd/fuse_virtio.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/contrib/virtiofsd/fuse_virtio.c b/contrib/virtiofsd/fuse_virtio.c
> index 083e4fc317..d543c6d30f 100644
> --- a/contrib/virtiofsd/fuse_virtio.c
> +++ b/contrib/virtiofsd/fuse_virtio.c
> @@ -507,18 +507,16 @@ static void *fv_queue_thread(void *opaque)
>                 ret = pthread_rwlock_rdlock(&qi->virtio_dev->vu_dispatch_rwlock);
>                 assert(ret == 0); /* there is no possible error case */
>  
> -               /* out is from guest, in is too guest */
> -               unsigned int in_bytes, out_bytes;
> -               vu_queue_get_avail_bytes(dev, q, &in_bytes, &out_bytes, ~0, ~0);
> +               if (se->debug) {
> +                       /* out is from guest, in is too guest */
> +                       unsigned int in_bytes, out_bytes;
> +                       vu_queue_get_avail_bytes(dev, q, &in_bytes, &out_bytes, ~0, ~0);
>  
> -               if (se->debug)
>                         fuse_debug("%s: Queue %d gave evalue: %zx available: in: %u out: %u\n",
>  				  __func__, qi->qidx, (size_t)evalue, in_bytes,
>  				  out_bytes);
> -
> -               if (!out_bytes) {
> -                       goto next;
>                 }
> +
>                 while (1) {
>                         bool allocated_bufv = false;
>                         struct fuse_bufvec bufv;
> @@ -708,7 +706,6 @@ static void *fv_queue_thread(void *opaque)
>                         elem = NULL;
>                  }
>  
> -next:
>                  pthread_rwlock_unlock(&qi->virtio_dev->vu_dispatch_rwlock);
>          }
>          pthread_mutex_destroy(&ch.lock);
> -- 
> 2.21.0
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK