Re: [PATCH 4/6] x86/cpu: Add platform ID to CPU info structure

From: Andy Shevchenko

Date: Tue Jan 20 2026 - 15:44:11 EST


On Tue, Jan 20, 2026 at 07:06:56AM -0800, Dave Hansen wrote:
> On 1/20/26 00:27, Andy Shevchenko wrote:
> ...
> >> Note: This should not grow the size of 'struct cpuinfo_x86' in
> >> practice since the u8 fits next to another u8 in the structure.
> >
> > Have you run `pahole` to confirm?
>
> I have not. If you'd like to contribute to the series by compiling this
> and running pahole on it, I'd very much appreciate it!

Okay, here is the diff:

--- old 2026-01-20 21:40:39.170530703 +0100
+++ new 2026-01-20 21:37:42.717138133 +0100
@@ -19,8 +19,9 @@
};

__u8 x86_stepping; /* 4 1 */
+ __u8 x86_platform_id; /* 5 1 */

- /* XXX 3 bytes hole, try to pack */
+ /* XXX 2 bytes hole, try to pack */

int x86_tlbsize; /* 8 4 */
__u32 vmx_capability[5]; /* 12 20 */
@@ -75,8 +76,8 @@

unsigned int initialized:1; /* 332: 8 4 */

- /* size: 336, cachelines: 6, members: 27 */
- /* sum members: 319, holes: 5, sum holes: 14 */
+ /* size: 336, cachelines: 6, members: 28 */
+ /* sum members: 320, holes: 5, sum holes: 13 */
/* sum bitfield members: 1 bits (0 bytes) */
/* bit_padding: 23 bits */
/* last cacheline: 16 bytes */

--
With Best Regards,
Andy Shevchenko