Re: [PATCH 3/3] tools: introduce parameter max_ranges.

From: Wei Liu <wei.liu2@citrix.com>
To: Paul Durrant <Paul.Durrant@citrix.com>
Cc: Kevin Tian <kevin.tian@intel.com>,
	"Keir (Xen.org)" <keir@xen.org>,
	"jbeulich@suse.com" <jbeulich@suse.com>,
	Andrew Cooper <Andrew.Cooper3@citrix.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Yu Zhang <yu.c.zhang@linux.intel.com>,
	"zhiyuan.lv@intel.com" <zhiyuan.lv@intel.com>,
	Stefano Stabellini <Stefano.Stabellini@citrix.com>,
	Wei Liu <wei.liu2@citrix.com>
Subject: Re: [PATCH 3/3] tools: introduce parameter max_ranges.
Date: Tue, 19 Jan 2016 14:37:25 +0000	[thread overview]
Message-ID: <20160119143725.GI1691@citrix.com> (raw)
In-Reply-To: <7a1e981ca15b491e878fb32287f5ea7a@AMSPEX02CL03.citrite.net>

On Tue, Jan 19, 2016 at 01:54:42PM +0000, Paul Durrant wrote:
> > -----Original Message-----
> > From: Wei Liu [mailto:wei.liu2@citrix.com]
> > Sent: 19 January 2016 11:54
> > To: Yu Zhang
> > Cc: xen-devel@lists.xen.org; Kevin Tian; Keir (Xen.org); Stefano Stabellini;
> > Andrew Cooper; Paul Durrant; zhiyuan.lv@intel.com; jbeulich@suse.com;
> > Wei Liu
> > Subject: Re: [Xen-devel] [PATCH 3/3] tools: introduce parameter
> > max_ranges.
> > 
> > On Tue, Jan 19, 2016 at 05:27:58PM +0800, Yu Zhang wrote:
> > > A new parameter - max_ranges is added to set the upper limit of ranges
> > > to be tracked inside one ioreq server rangeset.
> > >
> > > Ioreq server uses a group of rangesets to track the I/O or memory
> > > resources to be emulated. The default value of this limit is set to
> > > 256. Yet there are circumstances under which the limit should exceed
> > > the default one. E.g. in XenGT, when tracking the per-process graphic
> > > translation tables on intel broadwell platforms, the number of page
> > > tables concerned will be several thousand(normally in this case, 8192
> > > could be a big enough value). Users who set his item explicitly are
> > > supposed to know the specific scenarios that necessitate this
> > > configuration.
> > >
> > > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> > > ---
> > >  docs/man/xl.cfg.pod.5           | 17 +++++++++++++++++
> > >  tools/libxl/libxl_dom.c         |  3 +++
> > >  tools/libxl/libxl_types.idl     |  1 +
> > >  tools/libxl/xl_cmdimpl.c        |  4 ++++
> > >  xen/arch/x86/hvm/hvm.c          |  7 ++++++-
> > >  xen/include/public/hvm/params.h |  5 ++++-
> > >  6 files changed, 35 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
> > > index 8899f75..562563d 100644
> > > --- a/docs/man/xl.cfg.pod.5
> > > +++ b/docs/man/xl.cfg.pod.5
> > > @@ -962,6 +962,23 @@ FIFO-based event channel ABI support up to
> > 131,071 event channels.
> > >  Other guests are limited to 4095 (64-bit x86 and ARM) or 1023 (32-bit
> > >  x86).
> > >
> > > +=item B<max_ranges=N>
> > > +
> > 
> > This name is too generic. I don't have better suggestion though.
> > 
> 
> I think the increased limit for XenGT need only be applied to wp mem ranges so perhaps the parameter name could be 'max_wp_memory_ranges'?
> 

What does "WP" mean? "Write Protected"?

Is this parameter closely related to IOREQ server? Should it contain
"ioreq" somehow?

Wei.