On 12/4/24 16:51, Tobias Huschle wrote:
In this simplified example, vertical low CPUs are parked generally.
This will later be adjusted by making the parked state dependent
on the overall utilization on the underlying hypervisor.
Vertical lows are always bound to the highest CPU IDs. This implies that
the three types of vertically polarized CPUs are always clustered by ID.
This has the following implications:
- There can be scheduler domains consisting of only vertical highs
- There can be scheduler domains consisting of only vertical lows
A sched domain can have combination of these two as well. Is that not
possible on s390?
Signed-off-by: Tobias Huschle <huschle@xxxxxxxxxxxxx>
---
arch/s390/include/asm/topology.h | 3 +++
arch/s390/kernel/topology.c | 5 +++++
2 files changed, 8 insertions(+)
diff --git a/arch/s390/include/asm/topology.h b/arch/s390/include/asm/topology.h
index cef06bffad80..e86afeccde35 100644
--- a/arch/s390/include/asm/topology.h
+++ b/arch/s390/include/asm/topology.h
@@ -99,6 +99,9 @@ static inline int numa_node_id(void)
#endif /* CONFIG_NUMA */
+#define arch_cpu_parked cpu_parked
+int cpu_parked(int cpu);
+
#include <asm-generic/topology.h>
#endif /* _ASM_S390_TOPOLOGY_H */
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 4f9c301a705b..1032b65da574 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -299,6 +299,11 @@ void store_topology(struct sysinfo_15_1_x *info)
stsi(info, 15, 1, topology_mnest_limit());
}
+int cpu_parked(int cpu)
+{
+ return smp_cpu_get_polarization(cpu) == POLARIZATION_VL;
+}
Curious to know how this smp_cpu_get_polarization gets updated at
runtime? is it done by add_cpus_to_mask?
+
static void __arch_update_dedicated_flag(void *arg)
{
if (topology_cpu_dedicated(smp_processor_id()))
