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authorRobert Richter <robert.richter@amd.com>2008-11-27 16:33:37 -0500
committerRobert Richter <robert.richter@amd.com>2008-12-10 08:20:15 -0500
commitbf589e32960181fa8cbca7bfdd92265e49dc2dfa (patch)
treea5690c62071771e2e325cb748d83fb1cc5565daa /drivers
parent229234ae4a5ed9376b2e0524da04b0e5edadbf76 (diff)
oprofile: adding cpu_buffer_entries()
This is in preparation for changes in the cpu buffer implementation. Signed-off-by: Robert Richter <robert.richter@amd.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/oprofile/buffer_sync.c31
-rw-r--r--drivers/oprofile/cpu_buffer.h27
2 files changed, 29 insertions, 29 deletions
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index 44f676c8a51d..aed286c3f16e 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -464,33 +464,6 @@ static inline int is_code(unsigned long val)
464} 464}
465 465
466 466
467/* "acquire" as many cpu buffer slots as we can */
468static unsigned long get_slots(struct oprofile_cpu_buffer *b)
469{
470 unsigned long head = b->head_pos;
471 unsigned long tail = b->tail_pos;
472
473 /*
474 * Subtle. This resets the persistent last_task
475 * and in_kernel values used for switching notes.
476 * BUT, there is a small window between reading
477 * head_pos, and this call, that means samples
478 * can appear at the new head position, but not
479 * be prefixed with the notes for switching
480 * kernel mode or a task switch. This small hole
481 * can lead to mis-attribution or samples where
482 * we don't know if it's in the kernel or not,
483 * at the start of an event buffer.
484 */
485 cpu_buffer_reset(b);
486
487 if (head >= tail)
488 return head - tail;
489
490 return head + (b->buffer_size - tail);
491}
492
493
494/* Move tasks along towards death. Any tasks on dead_tasks 467/* Move tasks along towards death. Any tasks on dead_tasks
495 * will definitely have no remaining references in any 468 * will definitely have no remaining references in any
496 * CPU buffers at this point, because we use two lists, 469 * CPU buffers at this point, because we use two lists,
@@ -576,11 +549,11 @@ void sync_buffer(int cpu)
576 /* Remember, only we can modify tail_pos */ 549 /* Remember, only we can modify tail_pos */
577 550
578#ifndef CONFIG_OPROFILE_IBS 551#ifndef CONFIG_OPROFILE_IBS
579 available = get_slots(cpu_buf); 552 available = cpu_buffer_entries(cpu_buf);
580 553
581 for (i = 0; i < available; ++i) { 554 for (i = 0; i < available; ++i) {
582#else 555#else
583 while (get_slots(cpu_buf)) { 556 while (cpu_buffer_entries(cpu_buf)) {
584#endif 557#endif
585 struct op_sample *s = cpu_buffer_read_entry(cpu_buf); 558 struct op_sample *s = cpu_buffer_read_entry(cpu_buf);
586 559
diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index e6089768ae66..6055b5678394 100644
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -81,6 +81,33 @@ struct op_sample *cpu_buffer_read_entry(struct oprofile_cpu_buffer *cpu_buf)
81 return &cpu_buf->buffer[cpu_buf->tail_pos]; 81 return &cpu_buf->buffer[cpu_buf->tail_pos];
82} 82}
83 83
84/* "acquire" as many cpu buffer slots as we can */
85static inline
86unsigned long cpu_buffer_entries(struct oprofile_cpu_buffer *b)
87{
88 unsigned long head = b->head_pos;
89 unsigned long tail = b->tail_pos;
90
91 /*
92 * Subtle. This resets the persistent last_task
93 * and in_kernel values used for switching notes.
94 * BUT, there is a small window between reading
95 * head_pos, and this call, that means samples
96 * can appear at the new head position, but not
97 * be prefixed with the notes for switching
98 * kernel mode or a task switch. This small hole
99 * can lead to mis-attribution or samples where
100 * we don't know if it's in the kernel or not,
101 * at the start of an event buffer.
102 */
103 cpu_buffer_reset(b);
104
105 if (head >= tail)
106 return head - tail;
107
108 return head + (b->buffer_size - tail);
109}
110
84/* transient events for the CPU buffer -> event buffer */ 111/* transient events for the CPU buffer -> event buffer */
85#define CPU_IS_KERNEL 1 112#define CPU_IS_KERNEL 1
86#define CPU_TRACE_BEGIN 2 113#define CPU_TRACE_BEGIN 2