On 29.05.2024 11:01, Roger Pau Monne wrote:
> When adjusting move_cleanup_count to account for CPUs that are offline also
> adjust old_cpu_mask, otherwise further calls to fixup_irqs() could subtract
> those again creating and create an imbalance in move_cleanup_count.
I'm in trouble with "creating"; I can't seem to be able to guess what you may
have meant.
> Fixes: 472e0b74c5c4 ('x86/IRQ: deal with move cleanup count state in
> fixup_irqs()')
> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
With the above clarified (adjustment can be done while committing)
Reviewed-by: Jan Beulich <jbeul...@suse.com>
> --- a/xen/arch/x86/irq.c
> +++ b/xen/arch/x86/irq.c
> @@ -2572,6 +2572,14 @@ void fixup_irqs(const cpumask_t *mask, bool verbose)
> desc->arch.move_cleanup_count -= cpumask_weight(affinity);
> if ( !desc->arch.move_cleanup_count )
> release_old_vec(desc);
> + else
> + /*
> + * Adjust old_cpu_mask to account for the offline CPUs,
> + * otherwise further calls to fixup_irqs() could subtract
> those
> + * again and possibly underflow the counter.
> + */
> + cpumask_and(desc->arch.old_cpu_mask, desc->arch.old_cpu_mask,
> + &cpu_online_map);
> }
While functionality-wise okay, imo it would be slightly better to use
"affinity" here as well, so that even without looking at context beyond
what's shown here there is a direct connection to the cpumask_weight()
call. I.e.
cpumask_andnot(desc->arch.old_cpu_mask, desc->arch.old_cpu_mask,
affinity);
Thoughts?
Jan
