Hi Ingo,

On Fri, 16 Jan 2009 11:53:24 +0100 Ingo Molnar <mingo@elte.hu> wrote:
>
> * Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> 
> > Today's linux-next build (powerpc allnoconfig) failed like this:
> > 
> > In file included from kernel/sched.c:1703:
> > kernel/sched_fair.c: In function 'adaptive_gran':
> > kernel/sched_fair.c:1324: error: 'struct sched_entity' has no member named 'avg_wakeup'
> > 
> > Caused by commit e52fb7c097238d34f4d8e2a596f8a3f85b0c0565
> > ("sched: prefer wakers") from the sched tree.
> 
> that commit builds just fine on x86 and on powerpc as well.

The build was an allnoconfig build, so CONFIG_SCHEDSTATS was not set.

> Also, at commit e52fb7c097238d34f4d8e2a596f8a3f85b0c0565 there's no 
> 'sched_entity' use on line 1324 of kernel/sched_fair.c. Could you tell me 
> the exact commit ID you got the build failure under?

Commit b88402a67e74222061d2f24aef90ee58d2a3f080 "Merge commit
'kmemleak/kmemleak'" (what you get if you remove the last two commits
form today's linux-next).

At that point, kernel/sched_fair.c contains (from line 1320):

static unsigned long
adaptive_gran(struct sched_entity *curr, struct sched_entity *se)
{
	u64 this_run = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
	u64 expected_wakeup = 2*se->avg_wakeup * cfs_rq_of(se)->nr_running;
	u64 gran = 0;

	if (this_run < expected_wakeup)
		gran = expected_wakeup - this_run;

	return min_t(s64, gran, sysctl_sched_wakeup_granularity);
}

That function was added by commit
e52fb7c097238d34f4d8e2a596f8a3f85b0c0565.  Also, at that commit, stuct
sched_entity (in sched.h) looks like this:

struct sched_entity {
	.
	.

	u64			last_wakeup;
	u64			avg_overlap;

#ifdef CONFIG_SCHEDSTATS
	u64			wait_start;
	u64			wait_max;
	.
	.

	u64			start_runtime;
	u64			avg_wakeup;

	.
	.
	u64			nr_wakeups_passive;
	u64			nr_wakeups_idle;
#endif

	.
	.
};

The two fields "start_runtime" and "avg_wakeup" were added by the
previous commit 831451ac4e44d3a20b581ce726ef1d1144373f7d "sched:
introduce avg_wakeup" but according to Peter's email, they were added in
the wrong place.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/