src/parsec/disk-image/parsec/parsec-benchmark/pkgs/libs/uptcpip/src/include/sys/bsd_buf_ring.h - public/gem5-resources - Git at Google

 /**************************************************************************
  *
  * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright notice,
  *    this list of conditions and the following disclaimer.
  *
  * 2. The name of Kip Macy nor the names of other
  *    contributors may be used to endorse or promote products derived from
  *    this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
  * $FreeBSD$
  *
  ***************************************************************************/

 #ifndef	_BSD_SYS_BUF_RING_H_
 #define	_BSD_SYS_BUF_RING_H_

 #include <machine/bsd_cpu.h>

 #if defined(INVARIANTS) && !defined(DEBUG_BUFRING)
 #define DEBUG_BUFRING 1
 #endif

 #ifdef DEBUG_BUFRING
 #include <sys/bsd_lock.h>
 #include <sys/bsd_mutex.h>
 #endif

 extern void mtx_lock(struct mtx *m);
 extern void mtx_unlock(struct mtx * m);

 struct buf_ring {
 	volatile uint32_t	br_prod_head;
 	volatile uint32_t	br_prod_tail;
 	int              	br_prod_size;
 	int              	br_prod_mask;
 	uint64_t		br_drops;
 	uint64_t		br_prod_bufs;
 	uint64_t		br_prod_bytes;
 	/*
 	 * Pad out to next L2 cache line
 	 */
 	uint64_t	  	_pad0[11];

 	volatile uint32_t	br_cons_head;
 	volatile uint32_t	br_cons_tail;
 	int		 	br_cons_size;
 	int              	br_cons_mask;

 	/*
 	 * Pad out to next L2 cache line
 	 */
 	uint64_t	  	_pad1[14];
 //#ifdef DEBUG_BUFRING
 	struct mtx		*br_lock;
 //#endif
 	void			*br_ring[0];
 };

 /*
  * multi-producer safe lock-free ring buffer enqueue
  *
  */
 static __inline int
 buf_ring_enqueue_bytes(struct buf_ring *br, void *buf, int nbytes)
 {
 	uint32_t prod_head, prod_next;
 	uint32_t cons_tail;
 	int success;
 #ifdef DEBUG_BUFRING
 	int i;
 	for (i = br->br_cons_head; i != br->br_prod_head;
 	     i = ((i + 1) & br->br_cons_mask))
 		if(br->br_ring[i] == buf)
 			panic("buf=%p already enqueue at %d prod=%d cons=%d",
 			    buf, i, br->br_prod_tail, br->br_cons_tail);
 #endif
 	//critical_enter();
 	mtx_lock(br->br_lock);
 	do {
 		prod_head = br->br_prod_head;
 		cons_tail = br->br_cons_tail;

 		prod_next = (prod_head + 1) & br->br_prod_mask;

 		if (prod_next == cons_tail) {
 			//critical_exit();
 			mtx_unlock(br->br_lock);
 			return (ENOBUFS);
 		}

 		success = atomic_cmpset_int(&br->br_prod_head, prod_head,
 		    prod_next);
 	} while (success == 0);
 #ifdef DEBUG_BUFRING
 	if (br->br_ring[prod_head] != NULL)
 		panic("dangling value in enqueue");
 #endif
 	br->br_ring[prod_head] = buf;
 	wmb(); //FIXME

 	/*
 	 * If there are other enqueues in progress
 	 * that preceeded us, we need to wait for them
 	 * to complete
 	 */
 	while (br->br_prod_tail != prod_head)
 		cpu_spinwait(); //FIXME
 	br->br_prod_bufs++;
 	br->br_prod_bytes += nbytes;
 	br->br_prod_tail = prod_next;
 	//critical_exit();
 	mtx_unlock(br->br_lock);
 	return (0);
 }

 static __inline int
 buf_ring_enqueue(struct buf_ring *br, void *buf)
 {

 	return (buf_ring_enqueue_bytes(br, buf, 0));
 }

 /*
  * multi-consumer safe dequeue
  *
  */
 static __inline void *
 buf_ring_dequeue_mc(struct buf_ring *br)
 {
 	uint32_t cons_head, cons_next;
 	uint32_t prod_tail;
 	void *buf;
 	int success;

 	//critical_enter();
 	mtx_lock(br->br_lock);
 	do {
 		cons_head = br->br_cons_head;
 		prod_tail = br->br_prod_tail;

 		cons_next = (cons_head + 1) & br->br_cons_mask;

 		if (cons_head == prod_tail) {
 			//critical_exit();
 			mtx_unlock(br->br_lock);
 			return (NULL);
 		}

 		success = atomic_cmpset_int(&br->br_cons_head, cons_head,
 		    cons_next);
 	} while (success == 0);

 	buf = br->br_ring[cons_head];
 #ifdef DEBUG_BUFRING
 	br->br_ring[cons_head] = NULL;
 #endif
 	rmb();

 	/*
 	 * If there are other dequeues in progress
 	 * that preceeded us, we need to wait for them
 	 * to complete
 	 */
 	while (br->br_cons_tail != cons_head)
 		cpu_spinwait();

 	br->br_cons_tail = cons_next;
 	//critical_exit();
 	mtx_unlock(br->br_lock);

 	return (buf);
 }

 /*
  * single-consumer dequeue
  * use where dequeue is protected by a lock
  * e.g. a network driver's tx queue lock
  */
 static __inline void *
 buf_ring_dequeue_sc(struct buf_ring *br)
 {
 	uint32_t cons_head, cons_next, cons_next_next;
 	uint32_t prod_tail;
 	void *buf;

 	cons_head = br->br_cons_head;
 	prod_tail = br->br_prod_tail;

 	cons_next = (cons_head + 1) & br->br_cons_mask;
 	cons_next_next = (cons_head + 2) & br->br_cons_mask;

 	if (cons_head == prod_tail)
 		return (NULL);

 #ifdef PREFETCH_DEFINED
 	if (cons_next != prod_tail) {
 		prefetch(br->br_ring[cons_next]);
 		if (cons_next_next != prod_tail)
 			prefetch(br->br_ring[cons_next_next]);
 	}
 #endif
 	br->br_cons_head = cons_next;
 	buf = br->br_ring[cons_head];

 #ifdef DEBUG_BUFRING
 	br->br_ring[cons_head] = NULL;
 	if (!mtx_owned(br->br_lock))
 		panic("lock not held on single consumer dequeue");
 	if (br->br_cons_tail != cons_head)
 		panic("inconsistent list cons_tail=%d cons_head=%d",
 		    br->br_cons_tail, cons_head);
 #endif
 	br->br_cons_tail = cons_next;
 	return (buf);
 }

 /*
  * return a pointer to the first entry in the ring
  * without modifying it, or NULL if the ring is empty
  * race-prone if not protected by a lock
  */
 static __inline void *
 buf_ring_peek(struct buf_ring *br)
 {

 #ifdef DEBUG_BUFRING
 	if ((br->br_lock != NULL) && !mtx_owned(br->br_lock))
 		panic("lock not held on single consumer dequeue");
 #endif
 	/*
 	 * I believe it is safe to not have a memory barrier
 	 * here because we control cons and tail is worst case
 	 * a lagging indicator so we worst case we might
 	 * return NULL immediately after a buffer has been enqueued
 	 */
 	if (br->br_cons_head == br->br_prod_tail)
 		return (NULL);

 	return (br->br_ring[br->br_cons_head]);
 }

 static __inline int
 buf_ring_full(struct buf_ring *br)
 {

 	return (((br->br_prod_head + 1) & br->br_prod_mask) == br->br_cons_tail);
 }

 static __inline int
 buf_ring_empty(struct buf_ring *br)
 {

 	return (br->br_cons_head == br->br_prod_tail);
 }

 static __inline int
 buf_ring_count(struct buf_ring *br)
 {

 	return ((br->br_prod_size + br->br_prod_tail - br->br_cons_tail)
 	    & br->br_prod_mask);
 }

 struct buf_ring *buf_ring_alloc(int count, struct malloc_type *type, int flags,
     struct mtx *);
 void buf_ring_free(struct buf_ring *br, struct malloc_type *type);


 #endif
	/**************************************************************************
	*
	* Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	*
	* 2. The name of Kip Macy nor the names of other
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	* POSSIBILITY OF SUCH DAMAGE.
	*
	* $FreeBSD$
	*
	***************************************************************************/

	#ifndef _BSD_SYS_BUF_RING_H_
	#define _BSD_SYS_BUF_RING_H_

	#include <machine/bsd_cpu.h>

	#if defined(INVARIANTS) && !defined(DEBUG_BUFRING)
	#define DEBUG_BUFRING 1
	#endif

	#ifdef DEBUG_BUFRING
	#include <sys/bsd_lock.h>
	#include <sys/bsd_mutex.h>
	#endif

	extern void mtx_lock(struct mtx *m);
	extern void mtx_unlock(struct mtx * m);

	struct buf_ring {
	volatile uint32_t br_prod_head;
	volatile uint32_t br_prod_tail;
	int br_prod_size;
	int br_prod_mask;
	uint64_t br_drops;
	uint64_t br_prod_bufs;
	uint64_t br_prod_bytes;
	/*
	* Pad out to next L2 cache line
	*/
	uint64_t _pad0[11];

	volatile uint32_t br_cons_head;
	volatile uint32_t br_cons_tail;
	int br_cons_size;
	int br_cons_mask;

	/*
	* Pad out to next L2 cache line
	*/
	uint64_t _pad1[14];
	//#ifdef DEBUG_BUFRING
	struct mtx *br_lock;
	//#endif
	void *br_ring[0];
	};

	/*
	* multi-producer safe lock-free ring buffer enqueue
	*
	*/
	static __inline int
	buf_ring_enqueue_bytes(struct buf_ring br, void buf, int nbytes)
	{
	uint32_t prod_head, prod_next;
	uint32_t cons_tail;
	int success;
	#ifdef DEBUG_BUFRING
	int i;
	for (i = br->br_cons_head; i != br->br_prod_head;
	i = ((i + 1) & br->br_cons_mask))
	if(br->br_ring[i] == buf)
	panic("buf=%p already enqueue at %d prod=%d cons=%d",
	buf, i, br->br_prod_tail, br->br_cons_tail);
	#endif
	//critical_enter();
	mtx_lock(br->br_lock);
	do {
	prod_head = br->br_prod_head;
	cons_tail = br->br_cons_tail;

	prod_next = (prod_head + 1) & br->br_prod_mask;

	if (prod_next == cons_tail) {
	//critical_exit();
	mtx_unlock(br->br_lock);
	return (ENOBUFS);
	}

	success = atomic_cmpset_int(&br->br_prod_head, prod_head,
	prod_next);
	} while (success == 0);
	#ifdef DEBUG_BUFRING
	if (br->br_ring[prod_head] != NULL)
	panic("dangling value in enqueue");
	#endif
	br->br_ring[prod_head] = buf;
	wmb(); //FIXME

	/*
	* If there are other enqueues in progress
	* that preceeded us, we need to wait for them
	* to complete
	*/
	while (br->br_prod_tail != prod_head)
	cpu_spinwait(); //FIXME
	br->br_prod_bufs++;
	br->br_prod_bytes += nbytes;
	br->br_prod_tail = prod_next;
	//critical_exit();
	mtx_unlock(br->br_lock);
	return (0);
	}

	static __inline int
	buf_ring_enqueue(struct buf_ring br, void buf)
	{

	return (buf_ring_enqueue_bytes(br, buf, 0));
	}

	/*
	* multi-consumer safe dequeue
	*
	*/
	static __inline void *
	buf_ring_dequeue_mc(struct buf_ring *br)
	{
	uint32_t cons_head, cons_next;
	uint32_t prod_tail;
	void *buf;
	int success;

	//critical_enter();
	mtx_lock(br->br_lock);
	do {
	cons_head = br->br_cons_head;
	prod_tail = br->br_prod_tail;

	cons_next = (cons_head + 1) & br->br_cons_mask;

	if (cons_head == prod_tail) {
	//critical_exit();
	mtx_unlock(br->br_lock);
	return (NULL);
	}

	success = atomic_cmpset_int(&br->br_cons_head, cons_head,
	cons_next);
	} while (success == 0);

	buf = br->br_ring[cons_head];
	#ifdef DEBUG_BUFRING
	br->br_ring[cons_head] = NULL;
	#endif
	rmb();

	/*
	* If there are other dequeues in progress
	* that preceeded us, we need to wait for them
	* to complete
	*/
	while (br->br_cons_tail != cons_head)
	cpu_spinwait();

	br->br_cons_tail = cons_next;
	//critical_exit();
	mtx_unlock(br->br_lock);

	return (buf);
	}

	/*
	* single-consumer dequeue
	* use where dequeue is protected by a lock
	* e.g. a network driver's tx queue lock
	*/
	static __inline void *
	buf_ring_dequeue_sc(struct buf_ring *br)
	{
	uint32_t cons_head, cons_next, cons_next_next;
	uint32_t prod_tail;
	void *buf;

	cons_head = br->br_cons_head;
	prod_tail = br->br_prod_tail;

	cons_next = (cons_head + 1) & br->br_cons_mask;
	cons_next_next = (cons_head + 2) & br->br_cons_mask;

	if (cons_head == prod_tail)
	return (NULL);

	#ifdef PREFETCH_DEFINED
	if (cons_next != prod_tail) {
	prefetch(br->br_ring[cons_next]);
	if (cons_next_next != prod_tail)
	prefetch(br->br_ring[cons_next_next]);
	}
	#endif
	br->br_cons_head = cons_next;
	buf = br->br_ring[cons_head];

	#ifdef DEBUG_BUFRING
	br->br_ring[cons_head] = NULL;
	if (!mtx_owned(br->br_lock))
	panic("lock not held on single consumer dequeue");
	if (br->br_cons_tail != cons_head)
	panic("inconsistent list cons_tail=%d cons_head=%d",
	br->br_cons_tail, cons_head);
	#endif
	br->br_cons_tail = cons_next;
	return (buf);
	}

	/*
	* return a pointer to the first entry in the ring
	* without modifying it, or NULL if the ring is empty
	* race-prone if not protected by a lock
	*/
	static __inline void *
	buf_ring_peek(struct buf_ring *br)
	{

	#ifdef DEBUG_BUFRING
	if ((br->br_lock != NULL) && !mtx_owned(br->br_lock))
	panic("lock not held on single consumer dequeue");
	#endif
	/*
	* I believe it is safe to not have a memory barrier
	* here because we control cons and tail is worst case
	* a lagging indicator so we worst case we might
	* return NULL immediately after a buffer has been enqueued
	*/
	if (br->br_cons_head == br->br_prod_tail)
	return (NULL);

	return (br->br_ring[br->br_cons_head]);
	}

	static __inline int
	buf_ring_full(struct buf_ring *br)
	{

	return (((br->br_prod_head + 1) & br->br_prod_mask) == br->br_cons_tail);
	}

	static __inline int
	buf_ring_empty(struct buf_ring *br)
	{

	return (br->br_cons_head == br->br_prod_tail);
	}

	static __inline int
	buf_ring_count(struct buf_ring *br)
	{

	return ((br->br_prod_size + br->br_prod_tail - br->br_cons_tail)
	& br->br_prod_mask);
	}

	struct buf_ring buf_ring_alloc(int count, struct malloc_type type, int flags,
	struct mtx *);
	void buf_ring_free(struct buf_ring br, struct malloc_type type);



	#endif