Re: [PATCH 3/4] block/mq-deadline: Stop using per-CPU counters

[Bart Van Assche <bvanassche@xxxxxxx>]

On 9/24/21 03:58, Damien Le Moal wrote:
> On 2021/09/24 8:27, Bart Van Assche wrote:
> > -/* I/O statistics for all I/O priorities (enum dd_prio). */
> > -struct io_stats {
> > -	struct io_stats_per_prio stats[DD_PRIO_COUNT];
> > +	uint32_t inserted;
> > +	uint32_t merged;
> > +	uint32_t dispatched;
> > +	atomic_t completed;
>
> Why not use 64-bits types (regular unsigned long long and atomic64_t) ?

Even 64-bit counters can overflow. Using 32-bit counters makes it easier to
trigger an overflow of these counters.

Thanks,

Bart.