Re: [PATCH v2 3/3] xen/mm: limit non-scrubbed allocations to a specific order

[Jan Beulich <jbeulich@xxxxxxxx>]

On 22.01.2026 13:55, Roger Pau Monné wrote:
> On Mon, Jan 19, 2026 at 05:13:25PM +0100, Jan Beulich wrote:
>> On 15.01.2026 12:18, Roger Pau Monne wrote:
>>> --- a/docs/misc/xen-command-line.pandoc
>>> +++ b/docs/misc/xen-command-line.pandoc
>>> @@ -1822,6 +1822,15 @@ Specify the deepest C-state CPUs are permitted to be 
>>> placed in, and
>>>  optionally the maximum sub C-state to be used used.  The latter only 
>>> applies
>>>  to the highest permitted C-state.
>>>  
>>> +### max-order-dirty
>>> +> `= <integer>`
>>> +
>>> +Specify the maximum allocation order allowed when scrubbing allocated pages
>>> +in-place.  The allocation is non-preemptive, and hence the value must be 
>>> keep
>>> +low enough to avoid hogging the CPU for too long.
>>> +
>>> +Defaults to `CONFIG_DIRTY_MAX_ORDER` or if unset to 
>>> `CONFIG_DOMU_MAX_ORDER`.
>>
>> This may end up misleading, as - despite their names - these aren't really
>> Kconfig settings that people could easily control in their builds.
> 
> But those have different default values depending on the architecture,
> hence I didn't know what else to reference to as the default.  I'm
> open to suggestions, but I think we need to reference some default
> value so the user knows where to look for.

I agree something needs saying. In the absence of anything better we may be
able to think of, perhaps simply clarify that these are #define-s in source,
not Kconfig settings?

Jan