On Wed, Aug 17, 2016 at 09:39:41PM +0200, Colin Vidal wrote: > On Mon, 2016-08-15 at 21:30 +0200, Colin Vidal wrote: > > Hello, > > > > At the beginning of __schedule (kernel/sched/core.c), the current > > task > > is get with rq->curr. I try to to understand why not directly using > > current instead?
> > - int cpu; > > > > - cpu = smp_processor_id(); > > - rq = cpu_rq(cpu); > > - prev = rq->curr; > > + rq = cpu_rq(smp_processor_id()); > > + prev = current; > > > > and it seems to work (only tested on x86-64), but... To simple? its more expensive, rq->curr is a simple dereference (and we need that cacheline anyway), while current is a weird macro that expands to potentially a lot of code, depending on the arch.
