Re: [PATCH v4 10/17] preempt: Introduce HAS_SEPARATE_PREEMPT_RESCHED_BITS

[Boqun Feng]

On Wed, Aug 05, 2026 at 12:45:04PM +0530, Shrikanth Hegde wrote:
> 
> Hi Boqun.
> 
> > > nit: This limit is because to have the same behavior as other case when
> > > NMI_BITS=4 right?
> > > It is not easy to infer that from comment.
> > > 
> > 
> > It's sort of design by implementation IIUC, previously because of
> > NMI_BITS=4, we could only support nesting level being 15. And here we
> > just want to keep the same behavior here.
> 
> That I understood.
> 
> > 
> > If your question is why 15 was a good number before this change, I guess
> > would be it's just a number that is neither too big or too small.
> 
> Its more about below comment. Something like below is better?
> 
> /* NMI nesting is represented in 4 bits. */
> 

Sounds good, I will apply this, thank you!

Regards,
Boqun

> > 
> > > > +		/* Maximum NMI nesting is 15. */		\
> > > > +		BUG_ON(__this_cpu_read(nmi_nesting) >= 15);	\
> > > > +		__this_cpu_inc(nmi_nesting);			\
> > > > +		preempt_count_set(preempt_count() | NMI_MASK);  \