On Fri, Apr 08, 2016 at 07:44:14PM +0200, Peter Zijlstra wrote:
> On Fri, Apr 08, 2016 at 02:55:22PM +0200, Frederic Weisbecker wrote:
> > > > @@ -4540,17 +4568,8 @@ static void cpu_load_update(struct rq *this_rq,
> > > > unsigned long this_load,
> > > >
> > > > /* scale is effectively 1 << i now, and >> i divides by
> > > > scale */
> > > >
> > > > - old_load = this_rq->cpu_load[i];
> > > #ifdef CONFIG_NO_HZ_COMMON
> > > > - old_load = decay_load_missed(old_load, pending_updates
> > > > - 1, i);
> > > > - if (tickless_load) {
> > > > - old_load -= decay_load_missed(tickless_load,
> > > > pending_updates - 1, i);
> > > > - /*
> > > > - * old_load can never be a negative value
> > > > because a
> > > > - * decayed tickless_load cannot be greater than
> > > > the
> > > > - * original tickless_load.
> > > > - */
> > > > - old_load += tickless_load;
> > > > - }
> > > #endif
> >
> > Ah sure, if you prefer it that way, I can do that.
>
> Yes please. I normally favour the thing you did, but here it makes
> tricky code that much harder to read.
So I tried and it warns about the unused variable tickless_load, so I
would need two scattered ifdeffery in the function:
@@ -4528,7 +4529,9 @@ decay_load_missed(unsigned long load, unsigned long
missed_updates, int idx)
static void cpu_load_update(struct rq *this_rq, unsigned long this_load,
unsigned long pending_updates)
{
+#ifdef CONFIG_NO_HZ_COMMON
unsigned long tickless_load = this_rq->cpu_load[0];
+#endif
int i, scale;
this_rq->nr_load_updates++;
@@ -4541,6 +4544,7 @@ static void cpu_load_update(struct rq *this_rq, unsigned
long this_load,
/* scale is effectively 1 << i now, and >> i divides by scale */
old_load = this_rq->cpu_load[i];
+#ifdef CONFIG_NO_HZ_COMMON
old_load = decay_load_missed(old_load, pending_updates - 1, i);
if (tickless_load) {
old_load -= decay_load_missed(tickless_load,
pending_updates - 1, i);
@@ -4551,6 +4555,7 @@ static void cpu_load_update(struct rq *this_rq, unsigned
long this_load,
*/
old_load += tickless_load;
}
+#endif
new_load = this_load;
/*
* Round up the averaging division if load is increasing. This
Are you still sure you don't want the ifdeffed inline function?
Thanks.
