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-rw-r--r--drivers/oprofile/buffer_sync.c1
-rw-r--r--drivers/oprofile/cpu_buffer.c12
-rw-r--r--drivers/oprofile/cpu_buffer.h28
3 files changed, 14 insertions, 27 deletions
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index aed286c3f16e..944a5832d9e4 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -548,6 +548,7 @@ void sync_buffer(int cpu)
548 548
549 /* Remember, only we can modify tail_pos */ 549 /* Remember, only we can modify tail_pos */
550 550
551 cpu_buffer_reset(cpu);
551#ifndef CONFIG_OPROFILE_IBS 552#ifndef CONFIG_OPROFILE_IBS
552 available = cpu_buffer_entries(cpu_buf); 553 available = cpu_buffer_entries(cpu_buf);
553 554
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index d6f5de686363..5cf7efe38e67 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -124,18 +124,6 @@ void end_cpu_work(void)
124 flush_scheduled_work(); 124 flush_scheduled_work();
125} 125}
126 126
127/* Resets the cpu buffer to a sane state. */
128void cpu_buffer_reset(struct oprofile_cpu_buffer *cpu_buf)
129{
130 /*
131 * reset these to invalid values; the next sample collected
132 * will populate the buffer with proper values to initialize
133 * the buffer
134 */
135 cpu_buf->last_is_kernel = -1;
136 cpu_buf->last_task = NULL;
137}
138
139/* compute number of available slots in cpu_buffer queue */ 127/* compute number of available slots in cpu_buffer queue */
140static unsigned long nr_available_slots(struct oprofile_cpu_buffer const *b) 128static unsigned long nr_available_slots(struct oprofile_cpu_buffer const *b)
141{ 129{
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 {
50 50
51DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer); 51DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer);
52 52
53void cpu_buffer_reset(struct oprofile_cpu_buffer *cpu_buf); 53/*
54 * Resets the cpu buffer to a sane state.
55 *
56 * reset these to invalid values; the next sample collected will
57 * populate the buffer with proper values to initialize the buffer
58 */
59static inline void cpu_buffer_reset(int cpu)
60{
61 struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu);
62
63 cpu_buf->last_is_kernel = -1;
64 cpu_buf->last_task = NULL;
65}
54 66
55static inline 67static inline
56struct op_sample *cpu_buffer_write_entry(struct oprofile_cpu_buffer *cpu_buf) 68struct 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)
88 unsigned long head = b->head_pos; 100 unsigned long head = b->head_pos;
89 unsigned long tail = b->tail_pos; 101 unsigned long tail = b->tail_pos;
90 102
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) 103 if (head >= tail)
106 return head - tail; 104 return head - tail;
107 105