Re: [PATCH v2] arch_topology: Introduce nr_possible_packages

On Tue, Jul 21, 2026 at 03:32:03PM +0100, Sudeep Holla wrote:
> On Tue, Jul 14, 2026 at 01:43:17PM +0800, Feng Tang wrote:
> > For multi-sockets platforms kernel or driver code may need the number
> > of packages to chose different code directions. Some architecture
> > already provides such kind of interface like x86, which is being used
> > in its architecture code and drivers.
> > 
> > Add similar interface 'nr_possible_packages' for platforms which can
> > get package topology information by parsing ACPI tables in boot phase,
> > which was verified to show the correct number of packages on some
> > 1-socket and 2-sockets production arm64 servers from different vendors.
> > 
> > It has been used locally by some arm64 PMU driver, and cross-socket
> > timer-consistency check code, which are to be posted.
> > 
> > Signed-off-by: Feng Tang <[email protected]>
> > ---
> >   since v1:
> >       * fix the potential overflow issue for 32b package ID (Sudeep)
> > 	  * add real use case in commit log (Sudeep)
> > 
> >   since RFC:
> >       * use EXPORT_SYMBOL_GPL instead of EXPORT_SYMBOL (Greg)
> 
> This is undone in this version, why ?
> 
> > 	  * change the possible max package ID to 2047 (Greg)
> > 	  * remove the CONFIG_ARM64/RISCV limit for 'nr_possible_packages' (Greg)
> 
> Again this is still there, misleading or v2 is back to RFC, /me confused.

Thanks for the review!

My fault! that I messed up with the locally saved RFC and V1 patch. I was
focusing on fixing the problems you mentioned.

> > 
> >   v1:  https://lore.kernel.org/lkml/[email protected]/ 
> 
> Comments about users is still ignored.

I described the user case in commit log of this version. It was
locally used by several drivers and other code, maybe I should
repost it together with those code.

btw, is there any problem with the new package accounting code?  

Thanks,
Feng

> -- 
> Regards,
> Sudeep
> 
> P.S.: Please avoid personal pings as it will not gain attention from other
> interested parties.