src/patches/suse-2.6.27.25/patches.arch/s390-07-03-topology-fix.diff

   1 From: Gerald Schaefer <geraldsc@de.ibm.com>
   2 Subject: kernel: fix cpu topology support
   3 References: bnc#464466
   4
   5 Symptom:     CPU topology changes aren't recognized by the scheduler.
   6 Problem:     The common code scheduler used to have a hook which could be
   7              called from architecture code to trigger a rebuild of all
   8              scheduling domains when cpu topology changed. This hook got
   9              removed errorneously. So cpu topology change notifications
  10              got lost.
  11 Solution:    Readd the hook. This patch also removes some unused code
  12              from the s390 specific cpu topology code.
  13
  14 Acked-by: John Jolly <jjolly@suse.de>
  15 ---
  16  arch/s390/kernel/topology.c |   35 ++++++++++-------------------------
  17  include/linux/topology.h    |    2 +-
  18  kernel/sched.c              |   16 +++++++++++++---
  19  3 files changed, 24 insertions(+), 29 deletions(-)
  20
  21 --- a/arch/s390/kernel/topology.c
  22 +++ b/arch/s390/kernel/topology.c
  23 @@ -14,6 +14,7 @@
  24  #include <linux/workqueue.h>
  25  #include <linux/cpu.h>
  26  #include <linux/smp.h>
  27 +#include <linux/cpuset.h>
  28  #include <asm/delay.h>
  29  #include <asm/s390_ext.h>
  30  #include <asm/sysinfo.h>
  31 @@ -64,7 +65,6 @@ static void topology_work_fn(struct work
  32  static struct tl_info *tl_info;
  33  static struct core_info core_info;
  34  static int machine_has_topology;
  35 -static int machine_has_topology_irq;
  36  static struct timer_list topology_timer;
  37  static void set_topology_timer(void);
  38  static DECLARE_WORK(topology_work, topology_work_fn);
  39 @@ -81,7 +81,7 @@ cpumask_t cpu_coregroup_map(unsigned int
  40
  41         cpus_clear(mask);
  42         if (!topology_enabled || !machine_has_topology)
  43 -               return cpu_present_map;
  44 +               return cpu_possible_map;
  45         spin_lock_irqsave(&topology_lock, flags);
  46         while (core) {
  47                 if (cpu_isset(cpu, core->mask)) {
  48 @@ -171,7 +171,7 @@ static void topology_update_polarization
  49         int cpu;
  50
  51         mutex_lock(&smp_cpu_state_mutex);
  52 -       for_each_present_cpu(cpu)
  53 +       for_each_possible_cpu(cpu)
  54                 smp_cpu_polarization[cpu] = POLARIZATION_HRZ;
  55         mutex_unlock(&smp_cpu_state_mutex);
  56  }
  57 @@ -202,7 +202,7 @@ int topology_set_cpu_management(int fc)
  58                 rc = ptf(PTF_HORIZONTAL);
  59         if (rc)
  60                 return -EBUSY;
  61 -       for_each_present_cpu(cpu)
  62 +       for_each_possible_cpu(cpu)
  63                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
  64         return rc;
  65  }
  66 @@ -211,11 +211,11 @@ static void update_cpu_core_map(void)
  67  {
  68         int cpu;
  69
  70 -       for_each_present_cpu(cpu)
  71 +       for_each_possible_cpu(cpu)
  72                 cpu_core_map[cpu] = cpu_coregroup_map(cpu);
  73  }
  74
  75 -void arch_update_cpu_topology(void)
  76 +int arch_update_cpu_topology(void)
  77  {
  78         struct tl_info *info = tl_info;
  79         struct sys_device *sysdev;
  80 @@ -224,7 +224,7 @@ void arch_update_cpu_topology(void)
  81         if (!machine_has_topology) {
  82                 update_cpu_core_map();
  83                 topology_update_polarization_simple();
  84 -               return;
  85 +               return 0;
  86         }
  87         stsi(info, 15, 1, 2);
  88         tl_to_cores(info);
  89 @@ -233,11 +233,12 @@ void arch_update_cpu_topology(void)
  90                 sysdev = get_cpu_sysdev(cpu);
  91                 kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
  92         }
  93 +       return 1;
  94  }
  95
  96  static void topology_work_fn(struct work_struct *work)
  97  {
  98 -       arch_reinit_sched_domains();
  99 +       rebuild_sched_domains();
 100  }
 101
 102  void topology_schedule_update(void)
 103 @@ -260,11 +261,6 @@ static void set_topology_timer(void)
 104         add_timer(&topology_timer);
 105  }
 106
 107 -static void topology_interrupt(__u16 code)
 108 -{
 109 -       schedule_work(&topology_work);
 110 -}
 111 -
 112  static int __init early_parse_topology(char *p)
 113  {
 114         if (strncmp(p, "on", 2))
 115 @@ -284,14 +280,7 @@ static int __init init_topology_update(v
 116                 goto out;
 117         }
 118         init_timer_deferrable(&topology_timer);
 119 -       if (machine_has_topology_irq) {
 120 -               rc = register_external_interrupt(0x2005, topology_interrupt);
 121 -               if (rc)
 122 -                       goto out;
 123 -               ctl_set_bit(0, 8);
 124 -       }
 125 -       else
 126 -               set_topology_timer();
 127 +       set_topology_timer();
 128  out:
 129         update_cpu_core_map();
 130         return rc;
 131 @@ -312,9 +301,6 @@ void __init s390_init_cpu_topology(void)
 132                 return;
 133         machine_has_topology = 1;
 134
 135 -       if (facility_bits & (1ULL << 51))
 136 -               machine_has_topology_irq = 1;
 137 -
 138         tl_info = alloc_bootmem_pages(PAGE_SIZE);
 139         info = tl_info;
 140         stsi(info, 15, 1, 2);
 141 @@ -338,5 +324,4 @@ void __init s390_init_cpu_topology(void)
 142         return;
 143  error:
 144         machine_has_topology = 0;
 145 -       machine_has_topology_irq = 0;
 146  }
 147 --- a/include/linux/topology.h
 148 +++ b/include/linux/topology.h
 149 @@ -49,7 +49,7 @@
 150         for_each_online_node(node)                      \
 151                 if (nr_cpus_node(node))
 152
 153 -void arch_update_cpu_topology(void);
 154 +int arch_update_cpu_topology(void);
 155
 156  /* Conform to ACPI 2.0 SLIT distance definitions */
 157  #define LOCAL_DISTANCE         10
 158 --- a/kernel/sched.c
 159 +++ b/kernel/sched.c
 160 @@ -7640,8 +7640,14 @@ static struct sched_domain_attr *dattr_c
 161   */
 162  static cpumask_t fallback_doms;
 163
 164 -void __attribute__((weak)) arch_update_cpu_topology(void)
 165 +/*
 166 + * arch_update_cpu_topology lets virtualized architectures update the
 167 + * cpu core maps. It is supposed to return 1 if the topology changed
 168 + * or 0 if it stayed the same.
 169 + */
 170 +int __attribute__((weak)) arch_update_cpu_topology(void)
 171  {
 172 +       return 0;
 173  }
 174
 175  /*
 176 @@ -7735,17 +7741,21 @@ void partition_sched_domains(int ndoms_n
 177                              struct sched_domain_attr *dattr_new)
 178  {
 179         int i, j, n;
 180 +       int top_changed;
 181
 182         mutex_lock(&sched_domains_mutex);
 183
 184         /* always unregister in case we don't destroy any domains */
 185         unregister_sched_domain_sysctl();
 186
 187 +       /* Let architecture update cpu core mappings. */
 188 +       top_changed = arch_update_cpu_topology();
 189 +
 190         n = doms_new ? ndoms_new : 0;
 191
 192         /* Destroy deleted domains */
 193         for (i = 0; i < ndoms_cur; i++) {
 194 -               for (j = 0; j < n; j++) {
 195 +               for (j = 0; j < n && !top_changed; j++) {
 196                         if (cpus_equal(doms_cur[i], doms_new[j])
 197                             && dattrs_equal(dattr_cur, i, dattr_new, j))
 198                                 goto match1;
 199 @@ -7765,7 +7775,7 @@ match1:
 200
 201         /* Build new domains */
 202         for (i = 0; i < ndoms_new; i++) {
 203 -               for (j = 0; j < ndoms_cur; j++) {
 204 +               for (j = 0; j < ndoms_cur && !top_changed; j++) {
 205                         if (cpus_equal(doms_new[i], doms_cur[j])
 206                             && dattrs_equal(dattr_new, i, dattr_cur, j))
 207                                 goto match2;