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RE: [Xen-devel] Re: [PATCH] libxl: fix xenstore connection when run in d

To: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Re: [PATCH] libxl: fix xenstore connection when run in domU
From: "Jun Zhu (Intern)" <Jun.Zhu@xxxxxxxxxx>
Date: Tue, 31 Aug 2010 10:36:41 +0100
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Thread-topic: [Xen-devel] Re: [PATCH] libxl: fix xenstore connection when run in domU

I don't think it is a good idea to let users decide which "open". If we check 
if it is in Dom0, it uses xs_daemon_open; if in DomU, it uses xs_domain_open. 
Is it better?

If it is always preferring xs_domain_open, the performance is not better than 
that of xs_daemon_open when running in Dom0.

Jun Zhu
Citrix Systems UK
From: Ian Campbell
Sent: Tuesday, August 31, 2010 5:15 AM
To: Jun Zhu (Intern)
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; dgdegra@xxxxxxxxxxxxx
Subject: Re: [Xen-devel] Re: [PATCH] libxl: fix xenstore connection when run in 

On Tue, 2010-08-31 at 10:05 +0100, Jun Zhu (Intern) wrote:
> Hi
> There are other places that use the xs_daemon_open in libxl. Is it necessory 
> to change them as follows?
>      ctx->xsh = xs_daemon_open();
> +    if (!ctx->xsh)
> +        ctx->xsh = xs_domain_open();
>      if (!ctx->xsh) {
>          XL_LOG_ERRNOVAL(ctx, XL_LOG_ERROR, errno,
>                          "cannot connect to xenstore");

I think we'd be better off introducing "libxl__xs_open" which does the
right thing and make the users to all use it.

Is there any harm in always preferring xs_domain_open, even if the
xenstore daemon happens to be co-located in the same domain?


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