Re: [Xen-devel] [RFC PATCH COLO v5 03/29] tools: libxl: introduce a new API libxl__domain_restore() to read qemu state

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Wed, Apr 01, 2015 at 02:41:39PM +0800, Yang Hongyang wrote:
> From: Wen Congyang <wency@xxxxxxxxxxxxxx>
> 
> Secondary vm is running in colo mode. So we will do
> the following things again and again:
> 1. suspend both primay vm and secondary vm
> 2. sync the state
> 3. resume both primary vm and secondary vm
> We will send qemu's state each time in step2, and
> slave's qemu should read it each time before resuming
> secondary vm. Introduce a new API libxl__domain_restore()
> to do it. This API should be called before resuming
> secondary vm.
> 
> Note: we should update qemu to support it.
> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> ---
>  tools/libxl/libxl.c          | 18 ++++++++++++++++++
>  tools/libxl/libxl_dom.c      | 26 ++++++++++++++++++++++++++
>  tools/libxl/libxl_internal.h |  4 ++++
>  tools/libxl/libxl_qmp.c      | 10 ++++++++++
>  4 files changed, 58 insertions(+)
> 
> diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> index 2a735b3..6e55afc 100644
> --- a/tools/libxl/libxl.c
> +++ b/tools/libxl/libxl.c
> @@ -510,6 +510,24 @@ int libxl_domain_rename(libxl_ctx *ctx, uint32_t domid,
>      return rc;
>  }
>  
> +int libxl__domain_restore(libxl__gc *gc, uint32_t domid)
> +{
> +    int rc = 0;
> +
> +    libxl_domain_type type = libxl__domain_type(gc, domid);
> +    if (type != LIBXL_DOMAIN_TYPE_HVM) {
> +        rc = ERROR_FAIL;

ERROR_INVAL?

> +        goto out;
> +    }
> +
> +    rc = libxl__domain_restore_device_model(gc, domid);
> +    if (rc)
> +        LOG(ERROR, "failed to restore device mode for domain %u:%d",
> +            domid, rc);
> +out:
> +    return rc;
> +}
> +
>  int libxl__domain_resume(libxl__gc *gc, uint32_t domid, int suspend_cancel)
>  {
>      int rc = 0;
> diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
> index d286851..fd0c5c2 100644
> --- a/tools/libxl/libxl_dom.c
> +++ b/tools/libxl/libxl_dom.c
> @@ -1343,6 +1343,32 @@ int libxl__domain_suspend_device_model(libxl__gc *gc,
>      return ret;
>  }
>  
> +int libxl__domain_restore_device_model(libxl__gc *gc, uint32_t domid)
> +{
> +    char *state_file;
> +    int rc;
> +
> +    switch (libxl__device_model_version_running(gc, domid)) {
> +    case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
> +        /* not supported now */
> +        return ERROR_FAIL;

           rc = ERROR_FAIL;
           break;


Please return rc at the end of this function.

> +    case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
> +        /*
> +         * This function may be called too many times for the same gc,
> +         * so we use NOGC, and free the memory before return to avoid
> +         * OOM.
> +         */

Hmm...

> +        state_file = libxl__sprintf(NOGC,
> +                                    XC_DEVICE_MODEL_RESTORE_FILE".%d",
> +                                    domid);
> +        rc = libxl__qmp_restore(gc, domid, state_file);
> +        free(state_file);
> +        return rc;
> +    default:
> +        return ERROR_INVAL;
> +    }
> +}
> +
>  int libxl__domain_resume_device_model(libxl__gc *gc, uint32_t domid)
>  {
>  
> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> index c1ea498..3b4e6c4 100644
[...]
> +int libxl__qmp_restore(libxl__gc *gc, int domid, const char *state_file)
> +{
> +    libxl__json_object *args = NULL;
> +
> +    qmp_parameters_add_string(gc, &args, "filename", (char *)state_file);

No need to cast state_file to char *.

Wei.

> +
> +    return qmp_run_command(gc, domid, "xen-load-devices-state", args,
> +                           NULL, NULL);
> +}
> +
>  static int qmp_change(libxl__gc *gc, libxl__qmp_handler *qmp,
>                        char *device, char *target, char *arg)
>  {
> -- 
> 1.9.1

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel