From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kai Huang Subject: Re: PML (Page Modification Logging) design for Xen Date: Tue, 24 Mar 2015 16:06:00 +0800 Message-ID: <55111AE8.1040603@linux.intel.com> References: <54DB129D.3060102@linux.intel.com> <54DB4294.1080406@citrix.com> <54DC1249.60507@linux.intel.com> <54E323C7020000780006089B@mail.emea.novell.com> <5511075D.8010006@linux.intel.com> <55112601020000780006CD5B@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55112601020000780006CD5B@mail.emea.novell.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: Jan Beulich Cc: Andrew Cooper , kevin.tian@intel.com, keir@xen.org, tim@xen.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 03/24/2015 03:53 PM, Jan Beulich wrote: >>>> On 24.03.15 at 07:42, wrote: >> On 02/17/2015 06:19 PM, Jan Beulich wrote: >>>>>> On 12.02.15 at 03:39, wrote: >>>> On 02/11/2015 07:52 PM, Andrew Cooper wrote: >>>>> On 11/02/15 08:28, Kai Huang wrote: >>>>>> Design >>>>>> ====== >>>>>> >>>>>> - PML feature is used globally >>>>>> >>>>>> A new Xen boot parameter, say 'opt_enable_pml', will be introduced to >>>>>> control PML feature detection, and PML feature will only be detected >>>>>> if opt_enable_pml = 1. Once PML feature is detected, it will be used >>>>>> for dirty logging for all domains globally. Currently we don't support >>>>>> to use PML on basis of per-domain as it will require additional >>>>>> control from XL tool. >>>>> Rather than adding in a new top level command line option for an ept >>>>> subfeature, it would be preferable to add an "ept=" option which has >>>>> "pml" as a sub boolean. >>>> Which is good to me, if Jan agrees. >>>> >>>> Jan, which do you prefer here? >>> A single "ept=" option as Andrew suggested. >> Hi Andrew, Jan, Tim, >> >> Sorry to bring this thread back. >> >> Regarding to the parameter to control PML, I plan to enable PML by >> default, in which case would a "ept=no-pml" be more reasonable to >> disable it manually? > Imo the default should be off at least initially. OK. > The command line > option parsing is (and should be) independent of the chosen > default anyway, i.e. overrides in either direction should be > possible. While the parse_ept_param function does support "ept=pml" and "ept=no-pml" both, I think in the comments of the function we should explicitly tell whether to use "ept=pml" (in case PML is off by default), or "ept=no-pml" (in case PML is on by default), otherwise "ept=pml,no-pml" is legal but obviously it doesn't make any sense (and looks this issue also exists in parse_iommu_param?). Thanks, -Kai > >> Actually by referring to "iommu=" parameter, I would like to do below >> changes. Is it good to you? > Looks okay. > > Jan > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel