From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH v8 05/11] xen: grant_table: implement
 grant_table_warn_active_grants()
Date: Mon, 13 Jul 2015 10:24:46 -0400
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To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu2@citrix.com>, Andrew Jones <drjones@redhat.com>, Keir Fraser <keir@xen.org>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>, Julien Grall <julien.grall@linaro.org>, Ian Jackson <ian.jackson@eu.citrix.com>, Olaf Hering <olaf@aepfle.de>, Tim Deegan <tim@xen.org>, David Vrabel <david.vrabel@citrix.com>, Jan Beulich <jbeulich@suse.com>, xen-devel@lists.xenproject.org, Daniel De Graaf <dgdegra@tycho.nsa.gov>
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On Mon, Jul 13, 2015 at 03:44:04PM +0200, Vitaly Kuznetsov wrote:
> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> writes:
> 
> > On Tue, Jun 23, 2015 at 06:11:47PM +0200, Vitaly Kuznetsov wrote:
> >> Log first 10 active grants of a domain. This function is going to be used
> >> for soft reset, active grants on this path usually mean misbehaving backends
> >> refusing to release their mappings on shutdown.
> >
> > Is there an particular reason 10 was choosen instead of 42 for example :-)
> >
> 
> I was inpired by dump_pageframe_info() :-)

Ah!
> 
> > Also the 10 should probably have an #define for it.
> >
> 
> Ok, any preferred place/name for such define?

I would say just include it at the start of the function (and #undef
at the end), and maybe later on (if you want to) do a cleanup patch for
this and dump_pageframe_info to be controlled by the same
'too long to display' logic.

Which I would say could be a function that :
 - if 'loglvl=info' is used would do the 10.
 - if 'loglvl=all', then there is no limit.

But that is such a minor thing.
> 
> > Not sure I understand the usage case - except for development uses
> > to report on the Xen console? But if that is the case why not
> > use the 'g' on the ring console?
> 
> If there is a misbehaving backend and this cases the domain to crash
> right after the soft reset 'g' option will not be available and it won't
> be clear what caused the domain to crash.

Aah, that is good information. Please include that in the commit.