Re: [PATCH v8 05/11] xen: grant_table: implement grant_table_warn_active_grants()

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

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.