LXR linux/drivers/oprofile/cpu

   1/**
   2 * @file cpu_buffer.h
   3 *
   4 * @remark Copyright 2002-2009 OProfile authors
   5 * @remark Read the file COPYING
   6 *
   7 * @author John Levon <levon@movementarian.org>
   8 * @author Robert Richter <robert.richter@amd.com>
   9 */
  10
  11#ifndef OPROFILE_CPU_BUFFER_H
  12#define OPROFILE_CPU_BUFFER_H
  13
  14#include <linux/types.h>
  15#include <linux/spinlock.h>
  16#include <linux/workqueue.h>
  17#include <linux/cache.h>
  18#include <linux/sched.h>
  19#include <linux/ring_buffer.h>
  20
  21struct task_struct;
  22
  23int alloc_cpu_buffers(void);
  24void free_cpu_buffers(void);
  25
  26void start_cpu_work(void);
  27void end_cpu_work(void);
  28
  29/* CPU buffer is composed of such entries (which are
  30 * also used for context switch notes)
  31 */
  32struct op_sample {
  33        unsigned long eip;
  34        unsigned long event;
  35        unsigned long data[0];
  36};
  37
  38struct op_entry;
  39
  40struct oprofile_cpu_buffer {
  41        unsigned long buffer_size;
  42        struct task_struct *last_task;
  43        int last_is_kernel;
  44        int tracing;
  45        unsigned long sample_received;
  46        unsigned long sample_lost_overflow;
  47        unsigned long backtrace_aborted;
  48        unsigned long sample_invalid_eip;
  49        int cpu;
  50        struct delayed_work work;
  51};
  52
  53DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer);
  54
  55/*
  56 * Resets the cpu buffer to a sane state.
  57 *
  58 * reset these to invalid values; the next sample collected will
  59 * populate the buffer with proper values to initialize the buffer
  60 */
  61static inline void op_cpu_buffer_reset(int cpu)
  62{
  63        struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu);
  64
  65        cpu_buf->last_is_kernel = -1;
  66        cpu_buf->last_task = NULL;
  67}
  68
  69/*
  70 * op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
  71 * called only if op_cpu_buffer_write_reserve() did not return NULL or
  72 * entry->event != NULL, otherwise entry->size or entry->event will be
  73 * used uninitialized.
  74 */
  75
  76struct op_sample
  77*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
  78int op_cpu_buffer_write_commit(struct op_entry *entry);
  79struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu);
  80unsigned long op_cpu_buffer_entries(int cpu);
  81
  82/* returns the remaining free size of data in the entry */
  83static inline
  84int op_cpu_buffer_add_data(struct op_entry *entry, unsigned long val)
  85{
  86        if (!entry->size)
  87                return 0;
  88        *entry->data = val;
  89        entry->size--;
  90        entry->data++;
  91        return entry->size;
  92}
  93
  94/* returns the size of data in the entry */
  95static inline
  96int op_cpu_buffer_get_size(struct op_entry *entry)
  97{
  98        return entry->size;
  99}
 100
 101/* returns 0 if empty or the size of data including the current value */
 102static inline
 103int op_cpu_buffer_get_data(struct op_entry *entry, unsigned long *val)
 104{
 105        int size = entry->size;
 106        if (!size)
 107                return 0;
 108        *val = *entry->data;
 109        entry->size--;
 110        entry->data++;
 111        return size;
 112}
 113
 114/* extra data flags */
 115#define KERNEL_CTX_SWITCH       (1UL << 0)
 116#define IS_KERNEL               (1UL << 1)
 117#define TRACE_BEGIN             (1UL << 2)
 118#define USER_CTX_SWITCH         (1UL << 3)
 119
 120#endif /* OPROFILE_CPU_BUFFER_H */
 121