linux/drivers/oprofile/cpu_buffer.h
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   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);
  28void flush_cpu_work(void);
  29
  30/* CPU buffer is composed of such entries (which are
  31 * also used for context switch notes)
  32 */
  33struct op_sample {
  34        unsigned long eip;
  35        unsigned long event;
  36        unsigned long data[0];
  37};
  38
  39struct op_entry;
  40
  41struct oprofile_cpu_buffer {
  42        unsigned long buffer_size;
  43        struct task_struct *last_task;
  44        int last_is_kernel;
  45        int tracing;
  46        unsigned long sample_received;
  47        unsigned long sample_lost_overflow;
  48        unsigned long backtrace_aborted;
  49        unsigned long sample_invalid_eip;
  50        int cpu;
  51        struct delayed_work work;
  52};
  53
  54DECLARE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);
  55
  56/*
  57 * Resets the cpu buffer to a sane state.
  58 *
  59 * reset these to invalid values; the next sample collected will
  60 * populate the buffer with proper values to initialize the buffer
  61 */
  62static inline void op_cpu_buffer_reset(int cpu)
  63{
  64        struct oprofile_cpu_buffer *cpu_buf = &per_cpu(op_cpu_buffer, cpu);
  65
  66        cpu_buf->last_is_kernel = -1;
  67        cpu_buf->last_task = NULL;
  68}
  69
  70/*
  71 * op_cpu_buffer_add_data() and op_cpu_buffer_write_commit() may be
  72 * called only if op_cpu_buffer_write_reserve() did not return NULL or
  73 * entry->event != NULL, otherwise entry->size or entry->event will be
  74 * used uninitialized.
  75 */
  76
  77struct op_sample
  78*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size);
  79int op_cpu_buffer_write_commit(struct op_entry *entry);
  80struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu);
  81unsigned long op_cpu_buffer_entries(int cpu);
  82
  83/* returns the remaining free size of data in the entry */
  84static inline
  85int op_cpu_buffer_add_data(struct op_entry *entry, unsigned long val)
  86{
  87        if (!entry->size)
  88                return 0;
  89        *entry->data = val;
  90        entry->size--;
  91        entry->data++;
  92        return entry->size;
  93}
  94
  95/* returns the size of data in the entry */
  96static inline
  97int op_cpu_buffer_get_size(struct op_entry *entry)
  98{
  99        return entry->size;
 100}
 101
 102/* returns 0 if empty or the size of data including the current value */
 103static inline
 104int op_cpu_buffer_get_data(struct op_entry *entry, unsigned long *val)
 105{
 106        int size = entry->size;
 107        if (!size)
 108                return 0;
 109        *val = *entry->data;
 110        entry->size--;
 111        entry->data++;
 112        return size;
 113}
 114
 115/* extra data flags */
 116#define KERNEL_CTX_SWITCH       (1UL << 0)
 117#define IS_KERNEL               (1UL << 1)
 118#define TRACE_BEGIN             (1UL << 2)
 119#define USER_CTX_SWITCH         (1UL << 3)
 120
 121#endif /* OPROFILE_CPU_BUFFER_H */
 122
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