Re: [Qemu-devel] [PATCH 15/17] migration: Test new fd infrastructure

[Daniel P. Berrange]

On Mon, Jan 23, 2017 at 10:32:19PM +0100, Juan Quintela wrote:
> We just send the address through the alternate channels and test that it
> is ok.
> 
> Signed-off-by: Juan Quintela <quint...@redhat.com>
> ---
>  migration/ram.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 4e530ea..95af694 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -432,8 +432,22 @@ static void *multifd_send_thread(void *opaque)
>      qemu_mutex_lock(&params->mutex);
>      while (!params->quit){
>          if (params->pages.num) {
> +            int i;
> +            int num;
> +
> +            num = params->pages.num;

Is this likely to be a small or a large value ? .....

>              params->pages.num = 0;
>              qemu_mutex_unlock(&params->mutex);
> +
> +            for(i=0; i < num; i++) {
> +                if (qio_channel_write(params->c,
> +                                      (const char 
> *)&params->pages.address[i],
> +                                      sizeof(uint8_t *), &error_abort)
> +                    != sizeof(uint8_t*)) {
> +                    /* Shuoudn't ever happen */
> +                    exit(-1);
> +                }
> +            }

If 'num' is large,then you would be better populating an iovec
and using qio_channel_writev() rather than sending one uint8_t *
at a time.


> @@ -605,8 +620,29 @@ static void *multifd_recv_thread(void *opaque)
>      qemu_mutex_lock(&params->mutex);
>      while (!params->quit){
>          if (params->pages.num) {
> +            int i;
> +            int num;
> +
> +            num = params->pages.num;
>              params->pages.num = 0;
>              qemu_mutex_unlock(&params->mutex);
> +
> +            for(i = 0; i < num; i++) {
> +                if (qio_channel_read(params->c,
> +                                     (char *)&recv_address,
> +                                     sizeof(uint8_t*), &error_abort)
> +                    != sizeof(uint8_t *)) {
> +                    /* shouldn't ever happen */
> +                    exit(-1);
> +                }
> +                if (recv_address != params->pages.address[i]) {
> +                    printf("We received %p what we were expecting %p (%d)\n",
> +                           recv_address,
> +                           params->pages.address[i], i);
> +                    exit(-1);
> +                }
> +            }

Same comment as above.

Regards,
Daniel
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