|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH] xen/grants: repurpose command line max options
On 14.03.2023 11:25, Roger Pau Monné wrote: > On Tue, Mar 14, 2023 at 11:04:21AM +0100, Jan Beulich wrote: >> On 14.03.2023 10:22, Roger Pau Monné wrote: >>> On Mon, Mar 13, 2023 at 05:55:09PM +0100, Jan Beulich wrote: >>>> On 13.03.2023 13:16, Roger Pau Monne wrote: >>>>> --- a/docs/misc/xen-command-line.pandoc >>>>> +++ b/docs/misc/xen-command-line.pandoc >>>>> @@ -1232,9 +1232,8 @@ The usage of gnttab v2 is not security supported on >>>>> ARM platforms. >>>>> >>>>> > Can be modified at runtime >>>>> >>>>> -Specify the maximum number of frames which any domain may use as part >>>>> -of its grant table. This value is an upper boundary of the per-domain >>>>> -value settable via Xen tools. >>>>> +Specify the default maximum number of frames which any domain may use as >>>>> part >>>>> +of its grant table unless a different value is specified at domain >>>>> creation. >>>>> >>>>> Dom0 is using this value for sizing its grant table. >>>> >>>> dom0less DomU-s do as well, at the very least, also ... >>>> >>>>> @@ -1245,9 +1244,10 @@ Dom0 is using this value for sizing its grant >>>>> table. >>>>> >>>>> > Can be modified at runtime >>>>> >>>>> -Specify the maximum number of frames to use as part of a domains >>>>> -maptrack array. This value is an upper boundary of the per-domain >>>>> -value settable via Xen tools. >>>>> +Specify the default maximum number of frames to use as part of a domains >>>>> +maptrack array unless a different value is specified at domain creation. >>>>> + >>>>> +Dom0 is using this value for sizing its maptrack array. >>>> >>>> ... here. And even ordinary DomU-s appear to default to that in the >>>> absence of a specific value in the guest config. IOW at the very least >>>> the info you add should not be misleading. Better would be if the pre- >>>> existing info was adjusted at the same time. >>> >>> Aren't domUs already clearly covered by the sentence: >>> >>> "Specify the default maximum number of frames to use as part of a >>> domains..." >> >> Hmm, yes, my attention was caught too much by the Dom0 statement. While ... >> >>> IMO dom0 needs to be explicitly mentioned because in that case the >>> value provided is not the one used by default, but rather the one that >>> gets used. >> >> ... explicitly mentioning Dom0 is fine, I still think this needs wording >> differently here, because Dom0 doesn't actively do anything with this >> value (and, as said, it can't even obtain it other than by probing how >> many mappings it can create). >> >>>> I also wonder about the specific wording down here: While the max grant >>>> table size can indeed be queried, this isn't the case for the maptrack >>>> array. A domain also doesn't need to know its size, so maybe "This value >>>> is used to size all domains' maptrack arrays, unless overridden by their >>>> guest config"? >>> >>> I think the wording I've added already conveys this meaning: >>> >>> "Specify the default maximum number of frames to use as part of a domains >>> maptrack array unless a different value is specified at domain creation." >> >> Well, I mean specifically the Dom0 related statement. >> >> Also to me "default maximum" reads odd (and slightly ambiguous). Would >> "default upper bound on the number of ..." perhaps be a little better? > > So what about using: > > "Specify the default upper bound on the number of frames which any > domain may use as part of its grant table unless a different value is > specified at domain creation. > > Note this value is the enforced upper bound for dom0." > > And similar for the maptrack option. SGTM. (Maybe soften a little by using "effective" instead of "enforced", but only if you don't mean to emphasize the "enforce" aspect.) Jan
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |