From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Tiejun" Subject: Re: [v4][PATCH 11/19] tools: introduce some new parameters to set rdm policy Date: Fri, 26 Jun 2015 17:36:19 +0800 Message-ID: <558D1D13.2010208@intel.com> References: <1435053450-25131-1-git-send-email-tiejun.chen@intel.com> <1435053450-25131-12-git-send-email-tiejun.chen@intel.com> <1435234395.32500.73.camel@citrix.com> <558D0F98.7020107@intel.com> <1435309027.32500.142.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1435309027.32500.142.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: Wei Liu , Stefano Stabellini , Ian Jackson , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org >> TODO: in the future this parameter may be further extended to allow >> specifying arbitrary regions, e.g. even those belonging to another >> platform as a preparation for live migration with passthrough devices. > > I don't think this needs to be explained in this document at all. > Whenever someone does that work they can update the docs to describe the > new functionality. Okay. > >> >> ... >> >>> >>>> + >>>> +"none" means we have nothing to do all reserved regions and ignore all policies, [snip] >> Just let me rephrase this, >> >> "none" means we don't check any reserved regions and then all rdm >> policies would be ignored, so guest just work as before. > > When or why would I write: > rdm = "none" > in my configuration file instead of just not saying anything? As you know we just have two options, "none" vs. "host". So we need a explicit flag as a default libxl value to work out our mechanism. +libxl_rdm_reserve_type = Enumeration("rdm_reserve_type", [ + (0, "none"), + (1, "host"), + ]) + We just think this name can make sense, right? > > >>> Having read all these docs I now know what all the options are, but I >>> still don't really know what I should write. I think an example or two >>> of real world usage would be helpful. >> >> Here I picked some code fragments to help you understand this, > > I meant an example or two in the documentation. > > The code fragment didn't answer my question either, but that's not > really the point. Do you mean I should write two example, respectively? #1. What is one actual conflict? #2. After we're trying to fix this conflict, #2.1 How will "strict" fail a VM? #2.2 How will "relaxed" impact on a VM? > >>> >>>> +Note this may be overridden by rdm_reserve option in PCI device configuration. >>>> + [snip] >>> Rather than "above" (which is quite a large block of text) you should >>> specifically mention the rdm option. >>> >> >> What about this? >> >> (HVM/x86 only) This is same as reserve option inside the rdm option >> but just specific to a given device, and "strict" is default here. > > Is strict the default everywhere or does it differ depending on the > context? The latter. We have two cases, a global case and a per device case, and they're different at this point. Thanks Tiejun