drivers/oprofile/cpu_buffer.h

   1 /**
   2  * @file cpu_buffer.h
   3  *
   4  * @remark Copyright 2002 OProfile authors
   5  * @remark Read the file COPYING
   6  *
   7  * @author John Levon <levon@movementarian.org>
   8  */
   9
  10 #ifndef OPROFILE_CPU_BUFFER_H
  11 #define OPROFILE_CPU_BUFFER_H
  12
  13 #include <linux/types.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/cache.h>
  17 #include <linux/sched.h>
  18 #include <linux/ring_buffer.h>
  19
  20 struct task_struct;
  21
  22 int alloc_cpu_buffers(void);
  23 void free_cpu_buffers(void);
  24
  25 void start_cpu_work(void);
  26 void end_cpu_work(void);
  27
  28 /* CPU buffer is composed of such entries (which are
  29  * also used for context switch notes)
  30  */
  31 struct op_sample {
  32         unsigned long eip;
  33         unsigned long event;
  34 };
  35
  36 struct op_entry {
  37         struct ring_buffer_event *event;
  38         struct op_sample *sample;
  39         unsigned long irq_flags;
  40 };
  41
  42 struct oprofile_cpu_buffer {
  43         volatile unsigned long head_pos;
  44         volatile unsigned long tail_pos;
  45         unsigned long buffer_size;
  46         struct task_struct *last_task;
  47         int last_is_kernel;
  48         int tracing;
  49         unsigned long sample_received;
  50         unsigned long sample_lost_overflow;
  51         unsigned long backtrace_aborted;
  52         unsigned long sample_invalid_eip;
  53         int cpu;
  54         struct delayed_work work;
  55 };
  56
  57 extern struct ring_buffer *op_ring_buffer_read;
  58 extern struct ring_buffer *op_ring_buffer_write;
  59 DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer);
  60
  61 /*
  62  * Resets the cpu buffer to a sane state.
  63  *
  64  * reset these to invalid values; the next sample collected will
  65  * populate the buffer with proper values to initialize the buffer
  66  */
  67 static inline void cpu_buffer_reset(int cpu)
  68 {
  69         struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu);
  70
  71         cpu_buf->last_is_kernel = -1;
  72         cpu_buf->last_task = NULL;
  73 }
  74
  75 static inline int cpu_buffer_write_entry(struct op_entry *entry)
  76 {
  77         entry->event = ring_buffer_lock_reserve(op_ring_buffer_write,
  78                                                 sizeof(struct op_sample),
  79                                                 &entry->irq_flags);
  80         if (entry->event)
  81                 entry->sample = ring_buffer_event_data(entry->event);
  82         else
  83                 entry->sample = NULL;
  84
  85         if (!entry->sample)
  86                 return -ENOMEM;
  87
  88         return 0;
  89 }
  90
  91 static inline int cpu_buffer_write_commit(struct op_entry *entry)
  92 {
  93         return ring_buffer_unlock_commit(op_ring_buffer_write, entry->event,
  94                                          entry->irq_flags);
  95 }
  96
  97 static inline struct op_sample *cpu_buffer_read_entry(int cpu)
  98 {
  99         struct ring_buffer_event *e;
 100         e = ring_buffer_consume(op_ring_buffer_read, cpu, NULL);
 101         if (e)
 102                 return ring_buffer_event_data(e);
 103         if (ring_buffer_swap_cpu(op_ring_buffer_read,
 104                                  op_ring_buffer_write,
 105                                  cpu))
 106                 return NULL;
 107         e = ring_buffer_consume(op_ring_buffer_read, cpu, NULL);
 108         if (e)
 109                 return ring_buffer_event_data(e);
 110         return NULL;
 111 }
 112
 113 /* "acquire" as many cpu buffer slots as we can */
 114 static inline unsigned long cpu_buffer_entries(int cpu)
 115 {
 116         return ring_buffer_entries_cpu(op_ring_buffer_read, cpu)
 117                 + ring_buffer_entries_cpu(op_ring_buffer_write, cpu);
 118 }
 119
 120 /* transient events for the CPU buffer -> event buffer */
 121 #define CPU_IS_KERNEL 1
 122 #define CPU_TRACE_BEGIN 2
 123 #define IBS_FETCH_BEGIN 3
 124 #define IBS_OP_BEGIN    4
 125
 126 #endif /* OPROFILE_CPU_BUFFER_H */