linux-2.6-630-sched-fix.patch

   1 diff -Nurp linux-2.6.22-620/fs/proc/proc_misc.c linux-2.6.22-630/fs/proc/proc_misc.c
   2 --- linux-2.6.22-620/fs/proc/proc_misc.c        2008-06-25 14:49:41.000000000 -0400
   3 +++ linux-2.6.22-630/fs/proc/proc_misc.c        2008-07-08 16:12:39.000000000 -0400
   4 @@ -779,6 +779,34 @@ static const struct file_operations proc
   5  };
   6  #endif
   7
   8 +extern char debug_630_dumped[4087];
   9 +static int show_debug_630(struct seq_file *p, void *v)
  10 +{
  11 +       seq_printf(p, "%s\n", debug_630_dumped);
  12 +       return 0;
  13 +}
  14 +
  15 +static int debug_630_open(struct inode *inode, struct file *filp)
  16 +{
  17 +       int res;
  18 +       struct seq_file *m;
  19 +
  20 +       res = single_open(filp, show_debug_630, NULL);
  21 +       if (!res) {
  22 +               m = filp->private_data;
  23 +               m->buf = kmalloc(4096, GFP_KERNEL);
  24 +               m->size = 4096;
  25 +       }
  26 +       return res;
  27 +}
  28 +
  29 +static const struct file_operations proc_debug_630_operations = {
  30 +       .open = debug_630_open,
  31 +       .read = seq_read,
  32 +       .llseek = seq_lseek,
  33 +       .release = single_release,
  34 +};
  35 +
  36  struct proc_dir_entry *proc_root_kcore;
  37
  38  void create_seq_entry(char *name, mode_t mode, const struct file_operations *f)
  39 @@ -871,4 +899,6 @@ void __init proc_misc_init(void)
  40                         entry->proc_fops = &proc_sysrq_trigger_operations;
  41         }
  42  #endif
  43 +
  44 +       create_seq_entry("debug_630", 0, &proc_debug_630_operations);
  45  }
  46 diff -Nurp linux-2.6.22-620/kernel/sched.c linux-2.6.22-630/kernel/sched.c
  47 --- linux-2.6.22-620/kernel/sched.c     2008-06-25 14:49:41.000000000 -0400
  48 +++ linux-2.6.22-630/kernel/sched.c     2008-07-07 16:29:49.000000000 -0400
  49 @@ -3635,6 +3635,12 @@ struct event_spec {
  50  };
  51  #endif
  52
  53 +/* Bypass the vx_unhold infinite loop */
  54 +unsigned int merry;
  55 +char debug_630_dumped[4087] = { [0] = '\0' };
  56 +EXPORT_SYMBOL(merry);
  57 +EXPORT_SYMBOL(debug_630_dumped);
  58 +
  59  asmlinkage void __sched schedule(void)
  60  {
  61         struct task_struct *prev, *next;
  62 @@ -3722,14 +3728,43 @@ need_resched_nonpreemptible:
  63
  64         cpu = smp_processor_id();
  65         vx_set_rq_time(rq, jiffies);
  66 +
  67 +       merry=0;
  68  try_unhold:
  69         vx_try_unhold(rq, cpu);
  70  pick_next:
  71
  72         if (unlikely(!rq->nr_running)) {
  73                 /* can we skip idle time? */
  74 -               if (vx_try_skip(rq, cpu))
  75 +               if (vx_try_skip(rq, cpu) && merry<10) {
  76 +                       merry++;
  77                         goto try_unhold;
  78 +               }
  79 +               else if (merry==10 && !*debug_630_dumped) {
  80 +                       char *ptr = debug_630_dumped;
  81 +#define append(...)    ptr += snprintf(ptr, ((debug_630_dumped + sizeof(debug_630_dumped)) - ptr), __VA_ARGS__)
  82 +
  83 +                       if (list_empty(&rq->hold_queue))
  84 +                               append("hold queue is empty\n");
  85 +                       else {
  86 +                               struct list_head *l, *n;
  87 +                               append("rq->norm_time = %lu, rq->idle_time = %lu, rq->idle_skip = %d\n",
  88 +                                       rq->norm_time, rq->idle_time, rq->idle_skip);
  89 +                               list_for_each_safe(l, n, &rq->hold_queue) {
  90 +                                       struct task_struct *p;
  91 +                                       struct _vx_sched_pc *sched_pc;
  92 +                                       struct vx_info *vxi;
  93 +
  94 +                                       p = list_entry(l, struct task_struct, run_list);
  95 +                                       vxi = p->vx_info;
  96 +                                       sched_pc = &vx_per_cpu(vxi, sched_pc, cpu);
  97 +
  98 +                                       append("%u: sched_pc->norm_time = %lu, sched_pc->idle_time = %lu\n", vxi->vx_id,
  99 +                                               sched_pc->norm_time, sched_pc->idle_time);
 100 +                               }
 101 +                       }
 102 +                       *ptr = '\0';
 103 +               }
 104
 105                 idle_balance(cpu, rq);
 106                 if (!rq->nr_running) {