Re: [PATCH] tools/xl: Remove the filelock when building VM if autoballooning is off

[Ian Jackson <ian.jackson@xxxxxxxxxx>]

Dmitry Isaykin writes ("[PATCH] tools/xl: Remove the filelock when building VM 
if autoballooning is off"):
> The presence of this filelock does not allow building several VMs at the same
> time. This filelock was added to prevent other xl instances from using memory
> freeed for the currently building VM in autoballoon mode.
> 
> Signed-off-by: Dmitry Isaykin <isaikin-dmitry@xxxxxxxxx>

Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>

This was deferred due to the Xen 4.13 freeze.  I found it in a todo
list of mine.  I think it should be committed and I will do so soon
unless someone objects.

Sorry for the delay, Dmitry!

Regards,
Ian.

>  tools/xl/xl_vmcontrol.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/xl/xl_vmcontrol.c b/tools/xl/xl_vmcontrol.c
> index a1d633795c..2b42bb487d 100644
> --- a/tools/xl/xl_vmcontrol.c
> +++ b/tools/xl/xl_vmcontrol.c
> @@ -873,9 +873,11 @@ int create_domain(struct domain_create *dom_info)
>  start:
>      assert(domid == INVALID_DOMID);
>  
> -    rc = acquire_lock();
> -    if (rc < 0)
> -        goto error_out;
> +    if (autoballoon) {
> +        rc = acquire_lock();
> +        if (rc < 0)
> +            goto error_out;
> +    }
>  
>      if (domid_soft_reset == INVALID_DOMID) {
>          if (!freemem(domid, &d_config.b_info)) {
> @@ -935,7 +937,8 @@ start:
>      if ( ret )
>          goto error_out;
>  
> -    release_lock();
> +    if (autoballoon)
> +        release_lock();
>  
>      if (restore_fd_to_close >= 0) {
>          if (close(restore_fd_to_close))
> @@ -1109,7 +1112,8 @@ start:
>      }
>  
>  error_out:
> -    release_lock();
> +    if (autoballoon)
> +        release_lock();
>      if (libxl_domid_valid_guest(domid)) {
>          libxl_domain_destroy(ctx, domid, 0);
>          domid = INVALID_DOMID;
> -- 
> 2.17.1
>