mm/mm_event.c

   1 #include <linux/mm.h>
   2 #include <linux/mm_event.h>
   3 #include <linux/sched.h>
   4 #include <linux/vmalloc.h>
   5 #include <linux/seq_file.h>
   6 #include <linux/debugfs.h>
   7
   8 #define CREATE_TRACE_POINTS
   9 #include <trace/events/mm_event.h>
  10 /* msec */
  11 static unsigned long period_ms = 500;
  12
  13 void mm_event_task_init(struct task_struct *tsk)
  14 {
  15         memset(tsk->mm_event, 0, sizeof(tsk->mm_event));
  16         tsk->next_period = 0;
  17 }
  18
  19 static void record_stat(void)
  20 {
  21         if (time_is_before_eq_jiffies(current->next_period)) {
  22                 int i;
  23
  24                 for (i = 0; i < MM_TYPE_NUM; i++) {
  25                         if (current->mm_event[i].count == 0)
  26                                 continue;
  27
  28                         trace_mm_event_record(i, &current->mm_event[i]);
  29                         memset(&current->mm_event[i], 0,
  30                                         sizeof(struct mm_event_task));
  31                 }
  32                 current->next_period = jiffies + msecs_to_jiffies(period_ms);
  33         }
  34 }
  35
  36 void mm_event_start(ktime_t *time)
  37 {
  38         *time = ktime_get();
  39 }
  40
  41 void mm_event_end(enum mm_event_type event, ktime_t start)
  42 {
  43         s64 elapsed = ktime_us_delta(ktime_get(), start);
  44
  45         current->mm_event[event].count++;
  46         current->mm_event[event].accm_lat += elapsed;
  47         if (elapsed > current->mm_event[event].max_lat)
  48                 current->mm_event[event].max_lat = elapsed;
  49         record_stat();
  50 }
  51
  52 static struct dentry *mm_event_root;
  53
  54 static int period_ms_set(void *data, u64 val)
  55 {
  56         if (val < 1 || val > ULONG_MAX)
  57                 return -EINVAL;
  58
  59         period_ms = (unsigned long)val;
  60         return 0;
  61 }
  62
  63 static int period_ms_get(void *data, u64 *val)
  64 {
  65         *val = period_ms;
  66         return 0;
  67 }
  68
  69 DEFINE_SIMPLE_ATTRIBUTE(period_ms_operations, period_ms_get,
  70                         period_ms_set, "%llu\n");
  71
  72 static int __init mm_event_init(void)
  73 {
  74         struct dentry *entry;
  75
  76         mm_event_root = debugfs_create_dir("mm_event", NULL);
  77         if (!mm_event_root) {
  78                 pr_warn("debugfs dir <mm_event> creation failed\n");
  79                 return PTR_ERR(mm_event_root);
  80         }
  81
  82         entry = debugfs_create_file("period_ms", 0644,
  83                         mm_event_root, NULL, &period_ms_operations);
  84
  85         if (IS_ERR(entry)) {
  86                 pr_warn("debugfs file mm_event_task creation failed\n");
  87                 debugfs_remove_recursive(mm_event_root);
  88                 return PTR_ERR(entry);
  89         }
  90
  91         return 0;
  92 }
  93 subsys_initcall(mm_event_init);