diff options
Diffstat (limited to 'drivers/oprofile/cpu_buffer.h')
| -rw-r--r-- | drivers/oprofile/cpu_buffer.h | 28 |
1 files changed, 13 insertions, 15 deletions
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h index 6055b5678394..895763f065e9 100644 --- a/drivers/oprofile/cpu_buffer.h +++ b/drivers/oprofile/cpu_buffer.h @@ -50,7 +50,19 @@ struct oprofile_cpu_buffer { DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer); -void cpu_buffer_reset(struct oprofile_cpu_buffer *cpu_buf); +/* + * Resets the cpu buffer to a sane state. + * + * reset these to invalid values; the next sample collected will + * populate the buffer with proper values to initialize the buffer + */ +static inline void cpu_buffer_reset(int cpu) +{ + struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu); + + cpu_buf->last_is_kernel = -1; + cpu_buf->last_task = NULL; +} static inline struct op_sample *cpu_buffer_write_entry(struct oprofile_cpu_buffer *cpu_buf) @@ -88,20 +100,6 @@ unsigned long cpu_buffer_entries(struct oprofile_cpu_buffer *b) unsigned long head = b->head_pos; unsigned long tail = b->tail_pos; - /* - * Subtle. This resets the persistent last_task - * and in_kernel values used for switching notes. - * BUT, there is a small window between reading - * head_pos, and this call, that means samples - * can appear at the new head position, but not - * be prefixed with the notes for switching - * kernel mode or a task switch. This small hole - * can lead to mis-attribution or samples where - * we don't know if it's in the kernel or not, - * at the start of an event buffer. - */ - cpu_buffer_reset(b); - if (head >= tail) return head - tail; |