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/*
* Copyright (c) 2016 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __included_ssvm_fifo_h__
#define __included_ssvm_fifo_h__
#include <vppinfra/clib.h>
#include <vppinfra/vec.h>
#include <vppinfra/mheap.h>
#include <vppinfra/heap.h>
#include <vppinfra/pool.h>
#include <vppinfra/format.h>
#include <pthread.h>
typedef enum
{
SVM_FIFO_TAG_NOT_HELD = 0,
SVM_FIFO_TAG_DEQUEUE,
SVM_FIFO_TAG_ENQUEUE,
} svm_lock_tag_t;
/** Out-of-order segment */
typedef struct
{
u32 next; /**< Next linked-list element pool index */
u32 prev; /**< Previous linked-list element pool index */
u32 fifo_position; /**< Start of segment, normalized*/
u32 length; /**< Length of segment */
} ooo_segment_t;
#define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
typedef struct
{
pthread_mutex_t mutex; /* 8 bytes */
pthread_cond_t condvar; /* 8 bytes */
svm_lock_tag_t tag;
volatile u32 cursize; /**< current fifo size */
volatile u8 has_event; /**< non-zero if deq event exists */
u32 owner_pid;
u32 nitems;
/* Backpointers */
u32 server_session_index;
u32 client_session_index;
u8 server_thread_index;
u8 client_thread_index;
CLIB_CACHE_LINE_ALIGN_MARK (end_shared);
u32 head;
CLIB_CACHE_LINE_ALIGN_MARK (end_consumer);
/* producer */
u32 tail;
ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
u32 ooos_list_head; /**< Head of out-of-order linked-list */
u32 ooos_newest; /**< Last segment to have been updated */
CLIB_CACHE_LINE_ALIGN_MARK (data);
} svm_fifo_t;
static inline int
svm_fifo_lock (svm_fifo_t * f, u32 pid, u32 tag, int nowait)
{
if (PREDICT_TRUE (nowait == 0))
pthread_mutex_lock (&f->mutex);
else
{
if (pthread_mutex_trylock (&f->mutex))
return -1;
}
f->owner_pid = pid;
f->tag = tag;
return 0;
}
static inline void
svm_fifo_unlock (svm_fifo_t * f)
{
f->owner_pid = 0;
f->tag = 0;
CLIB_MEMORY_BARRIER ();
pthread_mutex_unlock (&f->mutex);
}
static inline u32
svm_fifo_max_dequeue (svm_fifo_t * f)
{
return f->cursize;
}
static inline u32
svm_fifo_max_enqueue (svm_fifo_t * f)
{
return f->nitems - f->cursize;
}
static inline u8
svm_fifo_has_ooo_data (svm_fifo_t * f)
{
return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
}
/**
* Sets fifo event flag.
*
* @return 1 if flag was not set.
*/
always_inline u8
svm_fifo_set_event (svm_fifo_t * f)
{
/* Probably doesn't need to be atomic. Still, better avoid surprises */
return __sync_lock_test_and_set (&f->has_event, 1) == 0;
}
/**
* Unsets fifo event flag.
*/
always_inline void
svm_fifo_unset_event (svm_fifo_t * f)
{
/* Probably doesn't need to be atomic. Still, better avoid surprises */
__sync_lock_test_and_set (&f->has_event, 0);
}
svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
int svm_fifo_enqueue_nowait (svm_fifo_t * f, int pid, u32 max_bytes,
u8 * copy_from_here);
int svm_fifo_enqueue_with_offset (svm_fifo_t * f, int pid,
u32 offset, u32 required_bytes,
u8 * copy_from_here);
int svm_fifo_dequeue_nowait (svm_fifo_t * f, int pid, u32 max_bytes,
u8 * copy_here);
int svm_fifo_peek (svm_fifo_t * f, int pid, u32 offset, u32 max_bytes,
u8 * copy_here);
int svm_fifo_dequeue_drop (svm_fifo_t * f, int pid, u32 max_bytes);
always_inline ooo_segment_t *
svm_fifo_newest_ooo_segment (svm_fifo_t * f)
{
return f->ooo_segments + f->ooos_newest;
}
always_inline u32
ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s)
{
return ((f->nitems + s->fifo_position - f->tail) % f->nitems);
}
always_inline u32
ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s)
{
return ((f->nitems + s->fifo_position + s->length - f->tail) % f->nitems);
}
#endif /* __included_ssvm_fifo_h__ */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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