Hi Nick,
I stumbled over a problem in the sched_domain code in regard to
zSeries (s390). The problem seems to have been introduced by
ChangeSet 1.1837.3.11: [PATCH] sched: consolidate sched domains.
With z/VM it is possible to start with a small set of cpus and
later on add more if you need them. If I try to online one of
the "late" cpus the scheduler crashes in find_busiest group
because the sched_group for the late cpu is not in the linked
list of sched_groups (group->next is NULL at sched.c:4770).
I worked around that problem with the attached patch. Dunno if
this is the right way to do it but it works for me.
blue skies,
Martin.
diffstat:
kernel/sched.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -urN linux-2.6/kernel/sched.c linux-2.6-s390/kernel/sched.c
--- linux-2.6/kernel/sched.c Fri Sep 3 15:26:17 2004
+++ linux-2.6-s390/kernel/sched.c Fri Sep 3 15:26:26 2004
@@ -4358,7 +4358,7 @@
cpumask_t covered = CPU_MASK_NONE;
int i;
- for_each_cpu_mask(i, span) {
+ for_each_cpu_mask(i, cpu_possible_map) {
int group = group_fn(i);
struct sched_group *sg = &groups[group];
int j;