Re: [Multiple reverts] [RFC PATCH] build: include/compat: figure out which other compat headers are needed

[Jan Beulich <jbeulich@suse.com>]

On 12.01.2023 10:27, Anthony PERARD wrote:
> On Thu, Jan 12, 2023 at 08:46:23AM +0100, Jan Beulich wrote:
>> On 11.01.2023 23:29, Andrew Cooper wrote:
>>> The real hvm_op.h legitimately includes the real trace.h, therefore the
>>> compat hvm_op.h legitimately includes the compat trace.h too.  But
>>> generation of compat trace.h was made asymmetric because of 2c8fabb223.
>>>
>>> In hindsight, that's a public ABI breakage.  The current configuration
>>> of this build of the hypervisor has no legitimate bearing on the headers
>>> needing to be installed to /usr/include/xen.
>>>
>>> Or put another way, it is a breakage to require Xen to have
>>> CONFIG_COMPAT+CONFIG_TRACEBUFFER enabled in the build simply to get the
>>> public API headers generated properly.
>>
>> There are no public API headers which are generated. The compat headers
>> are generate solely for Xen's internal purposes (and hence there's also
>> no public ABI breakage). Since generation is slow, avoiding to generate
>> ones not needed during the build is helpful.
> 
> If only we could do the generation faster:
>     https://lore.kernel.org/xen-devel/20220614162248.40278-5-anthony.perard@citrix.com/
>     patch which takes care of the slower part of the generation (slower
>     at least for some compat headers).

Right, and I still have this in my folder waiting for a review (by someone
knowing Perl better than e.g. I do). Maybe you want to put on the agenda
of today's community call an item to see whether we can nominate someone
with enough Perl knowledge?

Jan