oprofile: simplify add_ibs_begin()

[safe/jmp/linux-2.6] / drivers / oprofile / cpu_buffer.h

diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h
index 6055b56..cd28abc 100644 (file)
--- a/drivers/oprofile/cpu_buffer.h
+++ b/drivers/oprofile/cpu_buffer.h
@@ -15,6 +15,7 @@
 #include <linux/workqueue.h>
 #include <linux/cache.h>
 #include <linux/sched.h>
+#include <linux/ring_buffer.h>
 
 struct task_struct;
 
@@ -32,6 +33,12 @@ struct op_sample {
        unsigned long event;
 };
 
+struct op_entry {
+       struct ring_buffer_event *event;
+       struct op_sample *sample;
+       unsigned long irq_flags;
+};
+
 struct oprofile_cpu_buffer {
        volatile unsigned long head_pos;
        volatile unsigned long tail_pos;
@@ -39,7 +46,6 @@ struct oprofile_cpu_buffer {
        struct task_struct *last_task;
        int last_is_kernel;
        int tracing;
-       struct op_sample *buffer;
        unsigned long sample_received;
        unsigned long sample_lost_overflow;
        unsigned long backtrace_aborted;
@@ -50,63 +56,24 @@ struct oprofile_cpu_buffer {
 
 DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer);
 
-void cpu_buffer_reset(struct oprofile_cpu_buffer *cpu_buf);
-
-static inline
-struct op_sample *cpu_buffer_write_entry(struct oprofile_cpu_buffer *cpu_buf)
-{
-       return &cpu_buf->buffer[cpu_buf->head_pos];
-}
-
-static inline
-void cpu_buffer_write_commit(struct oprofile_cpu_buffer *b)
+/*
+ * 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 op_cpu_buffer_reset(int cpu)
 {
-       unsigned long new_head = b->head_pos + 1;
-
-       /*
-        * Ensure anything written to the slot before we increment is
-        * visible
-        */
-       wmb();
+       struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu);
 
-       if (new_head < b->buffer_size)
-               b->head_pos = new_head;
-       else
-               b->head_pos = 0;
+       cpu_buf->last_is_kernel = -1;
+       cpu_buf->last_task = NULL;
 }
 
-static inline
-struct op_sample *cpu_buffer_read_entry(struct oprofile_cpu_buffer *cpu_buf)
-{
-       return &cpu_buf->buffer[cpu_buf->tail_pos];
-}
-
-/* "acquire" as many cpu buffer slots as we can */
-static inline
-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;
-
-       return head + (b->buffer_size - tail);
-}
+int op_cpu_buffer_write_entry(struct op_entry *entry);
+int op_cpu_buffer_write_commit(struct op_entry *entry);
+struct op_sample *op_cpu_buffer_read_entry(int cpu);
+unsigned long op_cpu_buffer_entries(int cpu);
 
 /* transient events for the CPU buffer -> event buffer */
 #define CPU_IS_KERNEL 1