4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Akshay Adiga <akshay.ad...@linux.vnet.ibm.com>
commit ac9816dcbab53c57bcf1d7b15370b08f1e284318 upstream.
Init all present cpus for deep states instead of "all possible" cpus.
Init fails if a possible cpu is guarded. Resulting in making only
non-deep states available for cpuidle/hotplug.
Stewart says, this means that for single threaded workloads, if you
guard out a CPU core you'll not get WoF (Workload Optimised
Frequency), which means that performance goes down when you wouldn't
expect it to.
Fixes: 77b54e9f213f ("powernv/powerpc: Add winkle support for offline cpus")
Cc: sta...@vger.kernel.org # v3.19+
Signed-off-by: Akshay Adiga <akshay.ad...@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/powerpc/platforms/powernv/idle.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -78,7 +78,7 @@ static int pnv_save_sprs_for_deep_states
uint64_t msr_val = MSR_IDLE;
uint64_t psscr_val = pnv_deepest_stop_psscr_val;
- for_each_possible_cpu(cpu) {
+ for_each_present_cpu(cpu) {
uint64_t pir = get_hard_smp_processor_id(cpu);
uint64_t hsprg0_val = (uint64_t)&paca[cpu];
@@ -741,7 +741,7 @@ static int __init pnv_init_idle_states(v
int cpu;
pr_info("powernv: idle: Saving PACA pointers of all CPUs in
their thread sibling PACA\n");
- for_each_possible_cpu(cpu) {
+ for_each_present_cpu(cpu) {
int base_cpu = cpu_first_thread_sibling(cpu);
int idx = cpu_thread_in_core(cpu);
int i;
