Re: [patch v5 06/19] x86/cpu: Provide a sane leaf 0xb/0x1f parser

From: Thomas Gleixner
Date: Mon Feb 12 2024 - 10:08:43 EST


On Mon, Feb 12 2024 at 16:00, Borislav Petkov wrote:
> On Mon, Feb 12, 2024 at 03:17:45PM +0100, Thomas Gleixner wrote:
>> Especially x2apic_shift is horrible and the comments of EBX are visually
>> impaired while with the C++ comments x2apic_shift looks natural and the
>> EBX comments are just open to the right and therefore simpler.
>
> I'd say, put comments *above* the member versus on the side. We don't
> like side comments, if you remember. :-)

In code, no. For struct definitions if they are strictly tabular
formatted, they are actually nice as they are more compact and take less
space than the above member variant.

// eax
u32 x2apic_shift : 5, // Number of bits to shift APIC ID right
// for the topology ID at the next level
: 27; // Reserved
// ebx
u32 num_processors : 16, // Number of processors at current level
: 16; // Reserved

versus:

/* eax */
/*
* Number of bits to shift APIC ID right for the topology ID
* at the next level
*/
u32 x2apic_shift : 5,
/* Reserved */
: 27;

/* ebx */
/* Number of processors at current level */
u32 num_processors : 16,
/* Reserved */
: 16;

This really makes my eyes bleed.