033601a32b
Impact: feature to permanently disable ring buffer This patch adds a API to the ring buffer code that will permanently disable the ring buffer from ever recording. This should only be called when some serious anomaly is detected, and the system may be in an unstable state. When that happens, shutting down the recording to the ring buffers may be appropriate. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
131 lines
3.8 KiB
C
131 lines
3.8 KiB
C
#ifndef _LINUX_RING_BUFFER_H
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#define _LINUX_RING_BUFFER_H
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#include <linux/mm.h>
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#include <linux/seq_file.h>
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struct ring_buffer;
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struct ring_buffer_iter;
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/*
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* Don't reference this struct directly, use functions below.
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*/
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struct ring_buffer_event {
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u32 type:2, len:3, time_delta:27;
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u32 array[];
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};
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/**
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* enum ring_buffer_type - internal ring buffer types
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*
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* @RINGBUF_TYPE_PADDING: Left over page padding
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* array is ignored
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* size is variable depending on how much
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* padding is needed
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*
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* @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
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* array[0] = time delta (28 .. 59)
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* size = 8 bytes
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*
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* @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
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* array[0] = tv_nsec
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* array[1] = tv_sec
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* size = 16 bytes
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*
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* @RINGBUF_TYPE_DATA: Data record
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* If len is zero:
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* array[0] holds the actual length
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* array[1..(length+3)/4-1] holds data
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* else
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* length = len << 2
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* array[0..(length+3)/4] holds data
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*/
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enum ring_buffer_type {
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RINGBUF_TYPE_PADDING,
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RINGBUF_TYPE_TIME_EXTEND,
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/* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
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RINGBUF_TYPE_TIME_STAMP,
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RINGBUF_TYPE_DATA,
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};
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unsigned ring_buffer_event_length(struct ring_buffer_event *event);
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void *ring_buffer_event_data(struct ring_buffer_event *event);
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/**
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* ring_buffer_event_time_delta - return the delta timestamp of the event
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* @event: the event to get the delta timestamp of
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*
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* The delta timestamp is the 27 bit timestamp since the last event.
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*/
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static inline unsigned
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ring_buffer_event_time_delta(struct ring_buffer_event *event)
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{
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return event->time_delta;
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}
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/*
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* size is in bytes for each per CPU buffer.
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*/
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struct ring_buffer *
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ring_buffer_alloc(unsigned long size, unsigned flags);
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void ring_buffer_free(struct ring_buffer *buffer);
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int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
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struct ring_buffer_event *
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ring_buffer_lock_reserve(struct ring_buffer *buffer,
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unsigned long length,
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unsigned long *flags);
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int ring_buffer_unlock_commit(struct ring_buffer *buffer,
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struct ring_buffer_event *event,
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unsigned long flags);
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int ring_buffer_write(struct ring_buffer *buffer,
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unsigned long length, void *data);
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struct ring_buffer_event *
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ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
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struct ring_buffer_event *
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ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
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struct ring_buffer_iter *
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ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
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void ring_buffer_read_finish(struct ring_buffer_iter *iter);
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struct ring_buffer_event *
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ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
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struct ring_buffer_event *
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ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
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void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
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int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
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unsigned long ring_buffer_size(struct ring_buffer *buffer);
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void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
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void ring_buffer_reset(struct ring_buffer *buffer);
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int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
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struct ring_buffer *buffer_b, int cpu);
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int ring_buffer_empty(struct ring_buffer *buffer);
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int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
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void ring_buffer_record_disable(struct ring_buffer *buffer);
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void ring_buffer_record_enable(struct ring_buffer *buffer);
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void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
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void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
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unsigned long ring_buffer_entries(struct ring_buffer *buffer);
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unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
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u64 ring_buffer_time_stamp(int cpu);
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void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
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void tracing_on(void);
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void tracing_off(void);
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void tracing_off_permanent(void);
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enum ring_buffer_flags {
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RB_FL_OVERWRITE = 1 << 0,
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};
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#endif /* _LINUX_RING_BUFFER_H */
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