releases/4.14.53/powerpc-powernv-cpuidle-init-all-present-cpus-for-deep-states.patch

   1 From ac9816dcbab53c57bcf1d7b15370b08f1e284318 Mon Sep 17 00:00:00 2001
   2 From: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
   3 Date: Wed, 16 May 2018 17:32:14 +0530
   4 Subject: powerpc/powernv/cpuidle: Init all present cpus for deep states
   5
   6 From: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
   7
   8 commit ac9816dcbab53c57bcf1d7b15370b08f1e284318 upstream.
   9
  10 Init all present cpus for deep states instead of "all possible" cpus.
  11 Init fails if a possible cpu is guarded. Resulting in making only
  12 non-deep states available for cpuidle/hotplug.
  13
  14 Stewart says, this means that for single threaded workloads, if you
  15 guard out a CPU core you'll not get WoF (Workload Optimised
  16 Frequency), which means that performance goes down when you wouldn't
  17 expect it to.
  18
  19 Fixes: 77b54e9f213f ("powernv/powerpc: Add winkle support for offline cpus")
  20 Cc: stable@vger.kernel.org # v3.19+
  21 Signed-off-by: Akshay Adiga <akshay.adiga@linux.vnet.ibm.com>
  22 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  23 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  24
  25 ---
  26  arch/powerpc/platforms/powernv/idle.c |    4 ++--
  27  1 file changed, 2 insertions(+), 2 deletions(-)
  28
  29 --- a/arch/powerpc/platforms/powernv/idle.c
  30 +++ b/arch/powerpc/platforms/powernv/idle.c
  31 @@ -78,7 +78,7 @@ static int pnv_save_sprs_for_deep_states
  32         uint64_t msr_val = MSR_IDLE;
  33         uint64_t psscr_val = pnv_deepest_stop_psscr_val;
  34
  35 -       for_each_possible_cpu(cpu) {
  36 +       for_each_present_cpu(cpu) {
  37                 uint64_t pir = get_hard_smp_processor_id(cpu);
  38                 uint64_t hsprg0_val = (uint64_t)&paca[cpu];
  39
  40 @@ -741,7 +741,7 @@ static int __init pnv_init_idle_states(v
  41                 int cpu;
  42
  43                 pr_info("powernv: idle: Saving PACA pointers of all CPUs in their thread sibling PACA\n");
  44 -               for_each_possible_cpu(cpu) {
  45 +               for_each_present_cpu(cpu) {
  46                         int base_cpu = cpu_first_thread_sibling(cpu);
  47                         int idx = cpu_thread_in_core(cpu);
  48                         int i;