Re: [PATCH bpf-next v2 11/26] rqspinlock: Add deadlock detection and recovery

[Kumar Kartikeya Dwivedi]

On Mon, 10 Feb 2025 at 11:21, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Thu, Feb 06, 2025 at 02:54:19AM -0800, Kumar Kartikeya Dwivedi wrote:
> > +#define RES_NR_HELD 32
> > +
> > +struct rqspinlock_held {
> > +     int cnt;
> > +     void *locks[RES_NR_HELD];
> > +};
>
> That cnt field makes the whole thing overflow a cacheline boundary.
> Making it 31 makes it fit again.

Makes sense, I can make RES_NR_HELD 31, it doesn't matter too much.
That's one less cacheline to pull into the local CPU during remote CPU reads.