Re: [PATCH] CHANGELOG.md: Make PV shim smaller by factoring out HVM-specific shadow code

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.03.2021 11:56, George Dunlap wrote:
> 
> 
>> On Mar 29, 2021, at 6:26 PM, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>>
>> On 29/03/2021 17:23, Jan Beulich wrote:
>>> On 29.03.2021 18:12, George Dunlap wrote:
>>>>> On Mar 25, 2021, at 7:08 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>>> On 24.03.2021 18:26, George Dunlap wrote:
>>>>>> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>>>>>> ---
>>>>>> Missed one from my list when creating the other series
>>>>>>
>>>>>> CC: Ian Jackson <ian.jackson@xxxxxxxxxx>
>>>>>> CC: Jan Beulich <jbeulich@xxxxxxxx>
>>>>>> CC: Roger Pau Monne <roger.pau@xxxxxxxxxx>
>>>>>> ---
>>>>>> CHANGELOG.md | 1 +
>>>>>> 1 file changed, 1 insertion(+)
>>>>>>
>>>>>> diff --git a/CHANGELOG.md b/CHANGELOG.md
>>>>>> index 15a22d6bde..49832ae017 100644
>>>>>> --- a/CHANGELOG.md
>>>>>> +++ b/CHANGELOG.md
>>>>>> @@ -18,6 +18,7 @@ The format is based on [Keep a 
>>>>>> Changelog](https://keepachangelog.com/en/1.0.0/)
>>>>>> - x86_emulate: Expanded testing for several instruction classes
>>>>>> - CI loop: Add Alpine Linux, Ubuntu Focal targets; drop CentOS 6
>>>>>> - CI loop: Add dom0less aarch64 smoke test
>>>>>> + - Factored out HVM-specific shadow code, allowing PV shim to be slimmer
>>>>> But shadow code doesn't get included by default in shim-exclusive
>>>>> builds (and others are unlikely to disable HVM).
>>>> Can you propose some better text please?
>>> Does this need mentioning here in the first place?
>>
>> I would recommend not.
>>
>> We've been doing incremental improvements for the shim for several
>> releases now, and in this case, we're literally talking a few kb of
>> code.  As we already align to 2M boundaries for superpage reasons, there
>> almost certainly isn't actually a reduction in runtime size.
> 
> I don’t understand why the two of you are downplaying your work so much.  
> Yes, these are all only incremental improvements; but they are improvements; 
> and the cumulative effect of loads of incremental improvements can be 
> significant.  Communicating to people just what the nature of all these 
> incremental improvements are is important.
> 
> I mean, look at the release notes for Go 1.15 [1].  It includes things like 
> this:
> 
> "JSEscape now consistently uses Unicode escapes (\u00XX), which are 
> compatible with JSON."
> 
> "go test -v now groups output by test name, rather than printing the test 
> name on each line."
> 
> Those sound far more trivial than “Even more shadow code has been moved to an 
> HVM-specific file”.
> 
> If the approach is going to be “SUPER IMPORTANT SPECIAL STUFF ONLY", I’d 
> recommend removing CHANGELOG.md.  Having an official list that says, “Well, 
> really, we only did 2 things this release” is going to be actively harmful.  

I don't think it needs to be "super important" only, but it ought to
be at least user visible / user recognizable imo.

Jan