s390/numa: re-add DIE sched_domain_topology_level

By accident this level has been removed by the NUMA infrastructure patch.
For non-NUMA systems with CPUs that span more than one book, this makes
the scheduler only use one of the books and the other books remain idle.

Fix this and re-add the missing level.

For NUMA and non-NUMA we have the following scheduling domains and groups:

 - SMT  (Groups: CPU threads)
 - MC   (Groups: Cores)
 - BOOK (Groups: Books)

For the non-NUMA case we have one last level scheduling domain:

 - DIE  (Groups: Whole system, has all CPUs -> cpu_cpu_mask)

For the NUMA case we have the following two last level scheduling domains:

 - DIE  (Groups: NUMA nodes -> cpu_cpu_mask -> returns node siblings)
 - NUMA (Groups: Whole system, has all CPUs -> created in sched_init_numa())

Fixes: e8054b654bf5 ("s390/numa: add topology tree infrastructure")
Reported-and-tested-by: Evgeny Cherkashin <Eugene.Crosser@ru.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 1fbe1f8..bf05e7f 100644 (file)
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -451,6 +451,7 @@ static struct sched_domain_topology_level s390_topology[] = {
        { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
        { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
        { cpu_book_mask, SD_INIT_NAME(BOOK) },
+       { cpu_cpu_mask, SD_INIT_NAME(DIE) },
        { NULL, },
 };