On Thu, 17 Mar 2016, Jens Axboe wrote:
> On 03/17/2016 01:20 PM, Thomas Gleixner wrote:
> > > This might be better, we need to start at -1 to not miss the first one...
> > > Still untested.
> >
> > > +static inline struct blk_mq_ctx *next_ctx(struct request_queue *q, int
> > > *i)
> > > +{
> > > + do {
> > > + (*i)++;
> > > + if (*i < q->nr_queues) {
> > > + if (cpu_possible(*i))
> > > + return per_cpu_ptr(q->queue_ctx, *i);
> > > + continue;
> > > + }
> > > + break;
> > > + } while (1);
> > > +
> > > + return NULL;
> > > +}
> > > +
> > > +#define queue_for_each_ctx(q, ctx, i)
> > > \
> > > + for ((i) = -1; (ctx = next_ctx((q), &(i))) != NULL;)
> > > +
> >
> > What's wrong with
> >
> > for_each_possible_cpu(cpu) {
> > ctx = per_cpu_ptr(q->queue_ctx, cpu);
> >
> > ....
> > }
> >
> > instead of hiding it behind an incomprehensible macro mess?
>
> We might not have mapped all of them.
blk_mq_init_cpu_queues() tells a different story and q->queue_ctx is a per_cpu
allocation.
Thanks,
tglx
