Re: [PATCH for-4.19?] xen/x86: pretty print interrupt CPU affinity masks

[Jan Beulich <jbeulich@xxxxxxxx>]

On 16.05.2024 19:13, Andrew Cooper wrote:
> On 15/05/2024 4:29 pm, Roger Pau Monne wrote:
>> Print the CPU affinity masks as numeric ranges instead of plain hexadecimal
>> bitfields.
>>
>> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>> ---
>>  xen/arch/x86/irq.c | 10 +++++-----
>>  1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
>> index 80ba8d9fe912..3b951d81bd6d 100644
>> --- a/xen/arch/x86/irq.c
>> +++ b/xen/arch/x86/irq.c
>> @@ -1934,10 +1934,10 @@ void do_IRQ(struct cpu_user_regs *regs)
>>                  if ( ~irq < nr_irqs && irq_desc_initialized(desc) )
>>                  {
>>                      spin_lock(&desc->lock);
>> -                    printk("IRQ%d a=%04lx[%04lx,%04lx] v=%02x[%02x] t=%s 
>> s=%08x\n",
>> -                           ~irq, *cpumask_bits(desc->affinity),
>> -                           *cpumask_bits(desc->arch.cpu_mask),
>> -                           *cpumask_bits(desc->arch.old_cpu_mask),
>> +                    printk("IRQ%d a={%*pbl}[{%*pbl},{%*pbl}] v=%02x[%02x] 
>> t=%s s=%08x\n",
> 
> Looking at this more closely, there's still some information obfuscation
> going on.
> 
> How about "... a={} o={} n={} v=..."
> 
> so affinity, old and new masks are all stated explicitly, instead of
> having to remember what the square brackets mean, and in particular that
> the masks are backwards?

Just one question: Why put old ahead of new? Aiui that's what you refer to
with "backwards", yet I don't see what's backwards about it. Old would
possibly matter only when the IRQ was recently moved, whereas new (actually:
Why "new"?) would matter at all times. I'd see "... a={} m={} o={} v=..."
as more appropriate.

Jan