[lttng-ust.git] / libringbuffer / frontend_types.h

#ifndef _LINUX_RING_BUFFER_FRONTEND_TYPES_H
#define _LINUX_RING_BUFFER_FRONTEND_TYPES_H

/*
 * linux/ringbuffer/frontend_types.h
 *
 * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Ring Buffer Library Synchronization Header (types).
 *
 * Author:
 *	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * See ring_buffer_frontend.c for more information on wait-free algorithms.
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <urcu/list.h>
#include <urcu/uatomic.h>
#include <urcu/ref.h>

#include "ust/core.h"

#include "usterr_signal_safe.h"
#include "config.h"
#include "backend_types.h"

/*
 * A switch is done during tracing or as a final flush after tracing (so it
 * won't write in the new sub-buffer).
 */
enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH };

/* channel: collection of per-cpu ring buffers. */
struct channel {
	int record_disabled;
	unsigned long commit_count_mask;	/*
						 * Commit count mask, removing
						 * the MSBs corresponding to
						 * bits used to represent the
						 * subbuffer index.
						 */

	struct channel_backend backend;		/* Associated backend */

	unsigned long switch_timer_interval;	/* Buffer flush (jiffies) */
	unsigned long read_timer_interval;	/* Reader wakeup (jiffies) */
	//wait_queue_head_t read_wait;		/* reader wait queue */
	int finalized;				/* Has channel been finalized */
	struct urcu_ref ref;			/* Reference count */
};

/* Per-subbuffer commit counters used on the hot path */
struct commit_counters_hot {
	union v_atomic cc;		/* Commit counter */
	union v_atomic seq;		/* Consecutive commits */
};

/* Per-subbuffer commit counters used only on cold paths */
struct commit_counters_cold {
	union v_atomic cc_sb;		/* Incremented _once_ at sb switch */
};

/* ring buffer state */
struct lib_ring_buffer {
	/* First 32 bytes cache-hot cacheline */
	union v_atomic offset;		/* Current offset in the buffer */
	struct commit_counters_hot *commit_hot;
					/* Commit count per sub-buffer */
	long consumed;			/*
					 * Current offset in the buffer
					 * standard atomic access (shared)
					 */
	int record_disabled;
	/* End of first 32 bytes cacheline */
	union v_atomic last_tsc;	/*
					 * Last timestamp written in the buffer.
					 */

	struct lib_ring_buffer_backend backend;	/* Associated backend */

	struct commit_counters_cold *commit_cold;
					/* Commit count per sub-buffer */
	long active_readers;		/*
					 * Active readers count
					 * standard atomic access (shared)
					 */
					/* Dropped records */
	union v_atomic records_lost_full;	/* Buffer full */
	union v_atomic records_lost_wrap;	/* Nested wrap-around */
	union v_atomic records_lost_big;	/* Events too big */
	union v_atomic records_count;	/* Number of records written */
	union v_atomic records_overrun;	/* Number of overwritten records */
	//wait_queue_head_t read_wait;	/* reader buffer-level wait queue */
	int finalized;			/* buffer has been finalized */
	//struct timer_list switch_timer;	/* timer for periodical switch */
	//struct timer_list read_timer;	/* timer for read poll */
	unsigned long get_subbuf_consumed;	/* Read-side consumed */
	unsigned long prod_snapshot;	/* Producer count snapshot */
	unsigned long cons_snapshot;	/* Consumer count snapshot */
	int get_subbuf:1;		/* Sub-buffer being held by reader */
	int switch_timer_enabled:1;	/* Protected by ring_buffer_nohz_lock */
	int read_timer_enabled:1;	/* Protected by ring_buffer_nohz_lock */
};

static inline
void *channel_get_private(struct channel *chan)
{
	return chan->backend.priv;
}

/*
 * Issue warnings and disable channels upon internal error.
 * Can receive struct lib_ring_buffer or struct lib_ring_buffer_backend
 * parameters.
 */
#define CHAN_WARN_ON(c, cond)						\
	({								\
		struct channel *__chan;					\
		int _____ret = unlikely(cond);				\
		if (_____ret) {						\
			if (__same_type(*(c), struct channel_backend))	\
				__chan = caa_container_of((void *) (c),	\
							struct channel, \
							backend);	\
			else if (__same_type(*(c), struct channel))	\
				__chan = (void *) (c);			\
			else						\
				BUG_ON(1);				\
			uatomic_inc(&__chan->record_disabled);		\
			WARN_ON(1);					\
		}							\
		_____ret;						\
	})

#endif /* _LINUX_RING_BUFFER_FRONTEND_TYPES_H */
Commit	Line	Data
852c2936 MD	1	#ifndef _LINUX_RING_BUFFER_FRONTEND_TYPES_H
	2	#define _LINUX_RING_BUFFER_FRONTEND_TYPES_H
	3
	4	/*
	5	* linux/ringbuffer/frontend_types.h
	6	*
	7	* (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*
	9	* Ring Buffer Library Synchronization Header (types).
	10	*
	11	* Author:
	12	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	13	*
	14	* See ring_buffer_frontend.c for more information on wait-free algorithms.
	15	*
	16	* Dual LGPL v2.1/GPL v2 license.
	17	*/
	18
14641deb MD	19	#include <urcu/list.h>
	20	#include <urcu/uatomic.h>
	21	#include <urcu/ref.h>
	22
	23	#include "ust/core.h"
	24
	25	#include "usterr_signal_safe.h"
4931a13e MD	26	#include "config.h"
4931a13e MD	27	#include "backend_types.h"
852c2936 MD	28
	29	/*
	30	* A switch is done during tracing or as a final flush after tracing (so it
	31	* won't write in the new sub-buffer).
	32	*/
	33	enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH };
	34
852c2936 MD	35	/* channel: collection of per-cpu ring buffers. */
852c2936 MD	36	struct channel {
14641deb	37	int record_disabled;
852c2936 MD	38	unsigned long commit_count_mask; /*
	39	* Commit count mask, removing
	40	* the MSBs corresponding to
	41	* bits used to represent the
	42	* subbuffer index.
	43	*/
	44
	45	struct channel_backend backend; /* Associated backend */
	46
	47	unsigned long switch_timer_interval; /* Buffer flush (jiffies) */
	48	unsigned long read_timer_interval; /* Reader wakeup (jiffies) */
14641deb	49	//wait_queue_head_t read_wait; /* reader wait queue */
852c2936	50	int finalized; /* Has channel been finalized */
14641deb	51	struct urcu_ref ref; /* Reference count */
852c2936 MD	52	};
	53
	54	/* Per-subbuffer commit counters used on the hot path */
	55	struct commit_counters_hot {
	56	union v_atomic cc; /* Commit counter */
	57	union v_atomic seq; /* Consecutive commits */
	58	};
	59
	60	/* Per-subbuffer commit counters used only on cold paths */
	61	struct commit_counters_cold {
	62	union v_atomic cc_sb; /* Incremented _once_ at sb switch */
	63	};
	64
852c2936 MD	65	/* ring buffer state */
	66	struct lib_ring_buffer {
	67	/* First 32 bytes cache-hot cacheline */
	68	union v_atomic offset; /* Current offset in the buffer */
	69	struct commit_counters_hot *commit_hot;
	70	/* Commit count per sub-buffer */
14641deb	71	long consumed; /*
852c2936 MD	72	* Current offset in the buffer
	73	* standard atomic access (shared)
	74	*/
14641deb	75	int record_disabled;
852c2936 MD	76	/* End of first 32 bytes cacheline */
	77	union v_atomic last_tsc; /*
	78	* Last timestamp written in the buffer.
	79	*/
	80
	81	struct lib_ring_buffer_backend backend; /* Associated backend */
	82
	83	struct commit_counters_cold *commit_cold;
	84	/* Commit count per sub-buffer */
14641deb	85	long active_readers; /*
852c2936 MD	86	* Active readers count
	87	* standard atomic access (shared)
	88	*/
	89	/* Dropped records */
	90	union v_atomic records_lost_full; /* Buffer full */
	91	union v_atomic records_lost_wrap; /* Nested wrap-around */
	92	union v_atomic records_lost_big; /* Events too big */
	93	union v_atomic records_count; /* Number of records written */
	94	union v_atomic records_overrun; /* Number of overwritten records */
14641deb	95	//wait_queue_head_t read_wait; /* reader buffer-level wait queue */
852c2936	96	int finalized; /* buffer has been finalized */
14641deb MD	97	//struct timer_list switch_timer; /* timer for periodical switch */
14641deb MD	98	//struct timer_list read_timer; /* timer for read poll */
852c2936 MD	99	unsigned long get_subbuf_consumed; /* Read-side consumed */
	100	unsigned long prod_snapshot; /* Producer count snapshot */
	101	unsigned long cons_snapshot; /* Consumer count snapshot */
	102	int get_subbuf:1; /* Sub-buffer being held by reader */
	103	int switch_timer_enabled:1; /* Protected by ring_buffer_nohz_lock */
	104	int read_timer_enabled:1; /* Protected by ring_buffer_nohz_lock */
	105	};
	106
	107	static inline
	108	void channel_get_private(struct channel chan)
	109	{
	110	return chan->backend.priv;
	111	}
	112
	113	/*
	114	* Issue warnings and disable channels upon internal error.
	115	* Can receive struct lib_ring_buffer or struct lib_ring_buffer_backend
	116	* parameters.
	117	*/
	118	#define CHAN_WARN_ON(c, cond) \
	119	({ \
	120	struct channel *__chan; \
	121	int _____ret = unlikely(cond); \
	122	if (_____ret) { \
	123	if (__same_type(*(c), struct channel_backend)) \
14641deb	124	__chan = caa_container_of((void *) (c), \
852c2936 MD	125	struct channel, \
	126	backend); \
	127	else if (__same_type(*(c), struct channel)) \
	128	__chan = (void *) (c); \
	129	else \
	130	BUG_ON(1); \
14641deb	131	uatomic_inc(&__chan->record_disabled); \
852c2936 MD	132	WARN_ON(1); \
	133	} \
	134	_____ret; \
	135	})
	136
	137	#endif /* _LINUX_RING_BUFFER_FRONTEND_TYPES_H */