/*
- * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Copyright (c) 2016-2019 Cisco and/or its affiliates.
+ * Copyright (c) 2019 Arm Limited
+ * Copyright (c) 2010-2017 Intel Corporation and/or its affiliates.
+ * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
+ * Inspired from DPDK rte_ring.h (SPSC only) (derived from freebsd bufring.h).
* 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:
#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;
+#include <vppinfra/rbtree.h>
/** 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 */
+ u32 start; /**< Start of segment, normalized*/
+ u32 length; /**< Length of segment */
} ooo_segment_t;
-#define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
+#define SVM_FIFO_TRACE (0)
+#define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
+#define SVM_FIFO_INVALID_SESSION_INDEX ((u32)~0)
+#define SVM_FIFO_INVALID_INDEX ((u32)~0)
+#define SVM_FIFO_MAX_EVT_SUBSCRIBERS 7
+
+typedef enum svm_fifo_deq_ntf_
+{
+ SVM_FIFO_NO_DEQ_NOTIF = 0, /**< No notification requested */
+ SVM_FIFO_WANT_DEQ_NOTIF = 1, /**< Notify on dequeue */
+ SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL = 2, /**< Notify on transition from full */
+ SVM_FIFO_WANT_DEQ_NOTIF_IF_EMPTY = 4, /**< Notify on transition to empty */
+} svm_fifo_deq_ntf_t;
typedef struct
{
- volatile u32 cursize; /**< current fifo size */
- u32 nitems;
- CLIB_CACHE_LINE_ALIGN_MARK (end_cursize);
+ u32 offset;
+ u32 len;
+ u32 action;
+} svm_fifo_trace_elem_t;
- pthread_mutex_t mutex; /* 8 bytes */
- pthread_cond_t condvar; /* 8 bytes */
- svm_lock_tag_t tag;
+typedef struct svm_fifo_chunk_
+{
+ u32 start_byte; /**< chunk start byte */
+ u32 length; /**< length of chunk in bytes */
+ struct svm_fifo_chunk_ *next; /**< pointer to next chunk in linked-lists */
+ rb_node_index_t rb_index; /**< node index if chunk in rbtree */
+ u8 data[0]; /**< start of chunk data */
+} svm_fifo_chunk_t;
- volatile u8 has_event; /**< non-zero if deq event exists */
- u32 owner_pid;
+typedef enum svm_fifo_flag_
+{
+ SVM_FIFO_F_MULTI_CHUNK = 1 << 0,
+ SVM_FIFO_F_GROW = 1 << 1,
+ SVM_FIFO_F_SHRINK = 1 << 2,
+ SVM_FIFO_F_COLLECT_CHUNKS = 1 << 3,
+ SVM_FIFO_F_LL_TRACKED = 1 << 4,
+ SVM_FIFO_F_SINGLE_THREAD_OWNED = 1 << 5,
+} svm_fifo_flag_t;
- /* 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);
+typedef struct _svm_fifo
+{
+ CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
+ u32 size; /**< size of the fifo in bytes */
+ u32 nitems; /**< usable size (size-1) */
+ svm_fifo_chunk_t *start_chunk;/**< first chunk in fifo chunk list */
+ svm_fifo_chunk_t *end_chunk; /**< end chunk in fifo chunk list */
+ rb_tree_t ooo_enq_lookup; /**< rbtree for ooo enq chunk lookup */
+ rb_tree_t ooo_deq_lookup; /**< rbtree for ooo deq chunk lookup */
+ u8 flags; /**< fifo flags */
+ u8 slice_index; /**< segment slice for fifo */
- /* producer */
- u32 tail;
+ CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
+ volatile u32 has_event; /**< non-zero if deq event exists */
+ u32 master_session_index; /**< session layer session index */
+ u32 client_session_index; /**< app session index */
+ u8 master_thread_index; /**< session layer thread index */
+ u8 client_thread_index; /**< app worker index */
+ i8 refcnt; /**< reference count */
+ u32 segment_manager; /**< session layer segment manager index */
+ u32 segment_index; /**< segment index in segment manager */
+ struct _svm_fifo *next; /**< next in freelist/active chain */
+ struct _svm_fifo *prev; /**< prev in active chain */
+ svm_fifo_chunk_t *new_chunks; /**< chunks yet to be added to list */
+ u32 size_decrement; /**< bytes to remove from fifo */
- ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
+ CLIB_CACHE_LINE_ALIGN_MARK (consumer);
+ u32 head; /**< fifo head position/byte */
+ svm_fifo_chunk_t *head_chunk; /**< tracks chunk where head lands */
+ svm_fifo_chunk_t *ooo_deq; /**< last chunk used for ooo dequeue */
+ volatile u32 want_deq_ntf; /**< producer wants nudge */
+ volatile u32 has_deq_ntf;
+
+ CLIB_CACHE_LINE_ALIGN_MARK (producer);
+ u32 tail; /**< fifo tail position/byte */
u32 ooos_list_head; /**< Head of out-of-order linked-list */
+ svm_fifo_chunk_t *tail_chunk; /**< tracks chunk where tail lands */
+ svm_fifo_chunk_t *ooo_enq; /**< last chunk used for ooo enqueue */
+ ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
u32 ooos_newest; /**< Last segment to have been updated */
+ volatile u8 n_subscribers; /**< Number of subscribers for io events */
+ u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
+
+#if SVM_FIFO_TRACE
+ svm_fifo_trace_elem_t *trace;
+#endif
- 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)
+typedef enum
{
- 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;
+ SVM_FIFO_EFULL = -2,
+ SVM_FIFO_EEMPTY = -3,
+} svm_fifo_err_t;
+
+typedef struct svm_fifo_seg_
+{
+ u8 *data;
+ u32 len;
+} svm_fifo_seg_t;
+
+#if SVM_FIFO_TRACE
+#define svm_fifo_trace_add(_f, _s, _l, _t) \
+{ \
+ svm_fifo_trace_elem_t *trace_elt; \
+ vec_add2(_f->trace, trace_elt, 1); \
+ trace_elt->offset = _s; \
+ trace_elt->len = _l; \
+ trace_elt->action = _t; \
+}
+#else
+#define svm_fifo_trace_add(_f, _s, _l, _t)
+#endif
+
+u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
+u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
+
+/**
+ * Load head and tail optimized for consumer
+ *
+ * Internal function.
+ */
+static inline void
+f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail)
+{
+ /* load-relaxed: consumer owned index */
+ *head = f->head;
+ /* load-acq: consumer foreign index (paired with store-rel in producer) */
+ *tail = clib_atomic_load_acq_n (&f->tail);
+}
+
+/** Load head and tail optimized for producer
+ *
+ * Internal function
+ */
+static inline void
+f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
+{
+ /* load relaxed: producer owned index */
+ *tail = f->tail;
+ /* load-acq: producer foreign index (paired with store-rel in consumer) */
+ *head = clib_atomic_load_acq_n (&f->head);
}
+/**
+ * Load head and tail independent of producer/consumer role
+ *
+ * Internal function.
+ */
static inline void
-svm_fifo_unlock (svm_fifo_t * f)
+f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail)
+{
+ /* load-acq : consumer foreign index (paired with store-rel) */
+ *tail = clib_atomic_load_acq_n (&f->tail);
+ /* load-acq : producer foriegn index (paired with store-rel) */
+ *head = clib_atomic_load_acq_n (&f->head);
+}
+
+/**
+ * Distance to a from b, i.e., a - b in the fifo
+ *
+ * Internal function.
+ */
+static inline u32
+f_distance_to (svm_fifo_t * f, u32 a, u32 b)
+{
+ return ((f->size + a - b) % f->size);
+}
+
+/**
+ * Distance from a to b, i.e., b - a in the fifo
+ *
+ * Internal function.
+ */
+static inline u32
+f_distance_from (svm_fifo_t * f, u32 a, u32 b)
+{
+ return ((f->size + b - a) % f->size);
+}
+
+/**
+ * Fifo current size, i.e., number of bytes enqueued
+ *
+ * Internal function.
+ */
+static inline u32
+f_cursize (svm_fifo_t * f, u32 head, u32 tail)
+{
+ return (head <= tail ? tail - head : f->size + tail - head);
+}
+
+/**
+ * Fifo free bytes, i.e., number of free bytes
+ *
+ * Internal function
+ */
+static inline u32
+f_free_count (svm_fifo_t * f, u32 head, u32 tail)
+{
+ return (f->nitems - f_cursize (f, head, tail));
+}
+
+/**
+ * Try to shrink fifo size.
+ *
+ * Internal function.
+ */
+void svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail);
+
+/**
+ * Create fifo of requested size
+ *
+ * Allocates fifo on current heap.
+ *
+ * @param size data size in bytes for fifo to be allocated. Will be
+ * rounded to the next highest power-of-two value.
+ * @return pointer to new fifo
+ */
+svm_fifo_t *svm_fifo_create (u32 size);
+/**
+ * Initialize fifo
+ *
+ * @param f fifo
+ * @param size size for fifo
+ */
+void svm_fifo_init (svm_fifo_t * f, u32 size);
+/**
+ * Initialize fifo chunks and rbtree
+ *
+ * @param f fifo
+ */
+void svm_fifo_init_chunks (svm_fifo_t * f);
+/**
+ * Allocate a fifo chunk on heap
+ *
+ * If the chunk is allocated on a fifo segment, this should be called
+ * with the segment's heap pushed.
+ *
+ * @param size chunk size in bytes. Will be rounded to the next highest
+ * power-of-two
+ * @return new chunk or 0 if alloc failed
+ */
+svm_fifo_chunk_t *svm_fifo_chunk_alloc (u32 size);
+/**
+ * Grow fifo size by adding chunk to chunk list
+ *
+ * If fifos are allocated on a segment, this should be called with
+ * the segment's heap pushed.
+ *
+ * @param f fifo to be extended
+ * @param c chunk or linked list of chunks to be added
+ */
+void svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c);
+/**
+ * Request to reduce fifo size by amount of bytes
+ *
+ * Because the producer might be enqueuing data when this is called, the
+ * actual size update is only applied when producer tries to enqueue new
+ * data, unless @param try_shrink is set.
+ *
+ * @param f fifo
+ * @param len number of bytes to remove from fifo. The actual number
+ * of bytes to be removed will be less or equal to this
+ * value.
+ * @param try_shrink flg to indicate if it's safe to try to shrink fifo
+ * size. It should be set only if this is called by the
+ * producer of if the producer is not using the fifo
+ * @return actual length fifo size will be reduced by
+ */
+int svm_fifo_reduce_size (svm_fifo_t * f, u32 len, u8 try_shrink);
+/**
+ * Removes chunks that are after fifo end byte
+ *
+ * Needs to be called with segment heap pushed.
+ *
+ * @param f fifo
+ */
+svm_fifo_chunk_t *svm_fifo_collect_chunks (svm_fifo_t * f);
+/**
+ * Free fifo and associated state
+ *
+ * @param f fifo
+ */
+void svm_fifo_free (svm_fifo_t * f);
+/**
+ * Cleanup fifo chunk lookup rb tree
+ *
+ * The rb tree is allocated in segment heap so this should be called
+ * with it pushed.
+ *
+ * @param f fifo to cleanup
+ */
+void svm_fifo_free_chunk_lookup (svm_fifo_t * f);
+/**
+ * Cleanup fifo ooo data
+ *
+ * The ooo data is allocated in producer process memory. The fifo
+ * segment heap should not be pushed.
+ *
+ * @param f fifo to cleanup
+ */
+void svm_fifo_free_ooo_data (svm_fifo_t * f);
+/**
+ * Init fifo head and tail
+ *
+ * @param f fifo
+ * @param head head value that will be matched to a chunk
+ * @param tail tail value that will be matched to a chunk
+ */
+void svm_fifo_init_pointers (svm_fifo_t * f, u32 head, u32 tail);
+/**
+ * Clone fifo
+ *
+ * Clones single/default chunk fifo. It does not work for fifos with
+ * multiple chunks.
+ */
+void svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf);
+/**
+ * Enqueue data to fifo
+ *
+ * Data is enqueued and tail pointer is updated atomically. If the new data
+ * enqueued partly overlaps or "touches" an out-of-order segment, said segment
+ * is "consumed" and the number of bytes returned is appropriately updated.
+ *
+ * @param f fifo
+ * @param len length of data to copy
+ * @param src buffer from where to copy the data
+ * @return number of contiguous bytes that can be consumed or error
+ */
+int svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src);
+/**
+ * Enqueue data to fifo with offset
+ *
+ * Data is enqueued without updating tail pointer. Instead, an out-of-order
+ * list of segments is generated and maintained. Fifo takes care of coalescing
+ * contiguous or overlapping segments.
+ *
+ * @param f fifo
+ * @param offset offset at which to copy the data
+ * @param len len of data to copy
+ * @param src buffer from where to copy the data
+ * @return 0 if enqueue was successful, error otherwise
+ */
+int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset, u32 len,
+ u8 * src);
+
+/**
+ * Advance tail pointer
+ *
+ * Useful for moving tail pointer after external enqueue.
+ *
+ * @param f fifo
+ * @param len number of bytes to add to tail
+ */
+void svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len);
+/**
+ * Overwrite fifo head with new data
+ *
+ * This should be typically used by dgram transport protocols that need
+ * to update the dgram header after dequeueing a chunk of data. It assumes
+ * that the dgram header is at most spread over two chunks.
+ *
+ * @param f fifo
+ * @param src src of new data
+ * @param len length of new data
+ */
+void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * src, u32 len);
+/**
+ * Dequeue data from fifo
+ *
+ * Data is dequeued to consumer provided buffer and head is atomically
+ * updated.
+ *
+ * @param f fifo
+ * @param len length of data to dequeue
+ * @param dst buffer to where to dequeue the data
+ * @return number of bytes dequeued or error
+ */
+int svm_fifo_dequeue (svm_fifo_t * f, u32 len, u8 * dst);
+/**
+ * Peek data from fifo
+ *
+ * Data is copied from requested offset into provided dst buffer. Head is
+ * not updated.
+ *
+ * @param f fifo
+ * @param offset offset from which to copy the data
+ * @param len length of data to copy
+ * @param dst buffer to where to dequeue the data
+ * @return number of bytes peeked
+ */
+int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 len, u8 * dst);
+/**
+ * Dequeue and drop bytes from fifo
+ *
+ * Advances fifo head by requested amount of bytes.
+ *
+ * @param f fifo
+ * @param len number of bytes to drop
+ * @return number of bytes dropped
+ */
+int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 len);
+/**
+ * Dequeue and drop all bytes from fifo
+ *
+ * Advances head to tail position.
+ *
+ * @param f fifo
+ */
+void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
+int svm_fifo_segments (svm_fifo_t * f, svm_fifo_seg_t * fs);
+void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_seg_t * fs);
+/**
+ * Add io events subscriber to list
+ *
+ * @param f fifo
+ * @param sub subscriber opaque index (typically app worker index)
+ */
+void svm_fifo_add_subscriber (svm_fifo_t * f, u8 sub);
+/**
+ * Remove io events subscriber form list
+ *
+ * @param f fifo
+ * @param sub subscriber index to be removed
+ */
+void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
+/**
+ * Number of out-of-order segments for fifo
+ *
+ * @param f fifo
+ * @return number of out of order segments
+ */
+u32 svm_fifo_n_ooo_segments (svm_fifo_t * f);
+/**
+ * First out-of-order segment for fifo
+ *
+ * @param f fifo
+ * @return first out-of-order segment for fifo
+ */
+ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
+/**
+ * Check if fifo is sane. Debug only.
+ *
+ * @param f fifo
+ * @return 1 if sane, 0 otherwise
+ */
+u8 svm_fifo_is_sane (svm_fifo_t * f);
+/**
+ * Declare this fifo is used by only a single thread.
+ * In this special case, fifo-growth can be done in an efficient way without delay.
+ *
+ * @param f fifo
+ * @return 1 if the fifo is already owned by another thread, 0 otherwise
+ */
+u8 svm_fifo_set_single_thread_owned (svm_fifo_t * f);
+format_function_t format_svm_fifo;
+
+/**
+ * Fifo max bytes to dequeue optimized for consumer
+ *
+ * @param f fifo
+ * @return max number of bytes that can be dequeued
+ */
+static inline u32
+svm_fifo_max_dequeue_cons (svm_fifo_t * f)
{
- f->owner_pid = 0;
- f->tag = 0;
- CLIB_MEMORY_BARRIER ();
- pthread_mutex_unlock (&f->mutex);
+ u32 tail, head;
+ f_load_head_tail_cons (f, &head, &tail);
+ return f_cursize (f, head, tail);
}
+/**
+ * Fifo max bytes to dequeue optimized for producer
+ *
+ * @param f fifo
+ * @return max number of bytes that can be dequeued
+ */
+static inline u32
+svm_fifo_max_dequeue_prod (svm_fifo_t * f)
+{
+ u32 tail, head;
+ f_load_head_tail_prod (f, &head, &tail);
+ return f_cursize (f, head, tail);
+}
+
+/**
+ * Fifo max bytes to dequeue
+ *
+ * Note: use producer or consumer specific functions for performance:
+ * @ref svm_fifo_max_dequeue_cons (svm_fifo_t *f)
+ * @ref svm_fifo_max_dequeue_prod (svm_fifo_t *f)
+ */
static inline u32
svm_fifo_max_dequeue (svm_fifo_t * f)
{
- return f->cursize;
+ u32 tail, head;
+ f_load_head_tail_all_acq (f, &head, &tail);
+ return f_cursize (f, head, tail);
+}
+
+/**
+ * Check if fifo is full optimized for producer
+ *
+ * @param f fifo
+ * @return 1 if fifo is full 0 otherwise
+ */
+static inline int
+svm_fifo_is_full_prod (svm_fifo_t * f)
+{
+ return (svm_fifo_max_dequeue_prod (f) == f->nitems);
+}
+
+/* Check if fifo is full.
+ *
+ * Note: use producer or consumer specific functions for performance.
+ * @ref svm_fifo_is_full_prod (svm_fifo_t * f)
+ * add cons version if needed
+ */
+static inline int
+svm_fifo_is_full (svm_fifo_t * f)
+{
+ return (svm_fifo_max_dequeue (f) == f->nitems);
+}
+
+/**
+ * Check if fifo is empty optimized for consumer
+ *
+ * @param f fifo
+ * @return 1 if fifo is empty 0 otherwise
+ */
+static inline int
+svm_fifo_is_empty_cons (svm_fifo_t * f)
+{
+ return (svm_fifo_max_dequeue_cons (f) == 0);
+}
+
+/**
+ * Check if fifo is empty optimized for producer
+ *
+ * @param f fifo
+ * @return 1 if fifo is empty 0 otherwise
+ */
+static inline int
+svm_fifo_is_empty_prod (svm_fifo_t * f)
+{
+ return (svm_fifo_max_dequeue_prod (f) == 0);
}
+/**
+ * Check if fifo is empty
+ *
+ * Note: use producer or consumer specific functions for perfomance.
+ * @ref svm_fifo_is_empty_cons (svm_fifo_t * f)
+ * @ref svm_fifo_is_empty_prod (svm_fifo_t * f)
+ */
+static inline int
+svm_fifo_is_empty (svm_fifo_t * f)
+{
+ return (svm_fifo_max_dequeue (f) == 0);
+}
+
+/**
+ * Check if fifo is wrapped
+ *
+ * @param f fifo
+ * @return 1 if 'normalized' head is ahead of tail
+ */
+static inline u8
+svm_fifo_is_wrapped (svm_fifo_t * f)
+{
+ u32 head, tail;
+ f_load_head_tail_all_acq (f, &head, &tail);
+ return head > tail;
+}
+
+/**
+ * Maximum number of bytes that can be enqueued into fifo
+ *
+ * Optimized for producer
+ *
+ * @param f fifo
+ * @return max number of bytes that can be enqueued into fifo
+ */
+static inline u32
+svm_fifo_max_enqueue_prod (svm_fifo_t * f)
+{
+ u32 head, tail;
+ f_load_head_tail_prod (f, &head, &tail);
+ if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SHRINK))
+ svm_fifo_try_shrink (f, head, tail);
+ return f_free_count (f, head, tail);
+}
+
+/* Maximum number of bytes that can be enqueued into fifo
+ *
+ * Note: use producer or consumer specific functions for performance.
+ * @ref svm_fifo_max_enqueue_prod (svm_fifo_t *f)
+ * add consumer specific version if needed.
+ */
static inline u32
svm_fifo_max_enqueue (svm_fifo_t * f)
{
- return f->nitems - svm_fifo_max_dequeue (f);
+ u32 head, tail;
+ f_load_head_tail_all_acq (f, &head, &tail);
+ if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SHRINK))
+ svm_fifo_try_shrink (f, head, tail);
+ return f_free_count (f, head, tail);
+}
+
+/**
+ * Max contiguous chunk of data that can be read
+ */
+static inline u32
+svm_fifo_max_read_chunk (svm_fifo_t * f)
+{
+ u32 head, tail;
+ f_load_head_tail_cons (f, &head, &tail);
+ return tail >= head ? (tail - head) : (f->size - head);
+}
+
+/**
+ * Max contiguous chunk of data that can be written
+ */
+static inline u32
+svm_fifo_max_write_chunk (svm_fifo_t * f)
+{
+ u32 head, tail;
+ f_load_head_tail_prod (f, &head, &tail);
+ return tail >= head ? f->size - tail : f_free_count (f, head, tail);
+}
+
+static inline u8 *
+svm_fifo_head (svm_fifo_t * f)
+{
+ /* load-relaxed: consumer owned index */
+ return (f->head_chunk->data + (f->head - f->head_chunk->start_byte));
+}
+
+static inline u8 *
+svm_fifo_tail (svm_fifo_t * f)
+{
+ /* load-relaxed: producer owned index */
+ return (f->tail_chunk->data + (f->tail - f->tail_chunk->start_byte));
}
+static inline u8
+svm_fifo_n_subscribers (svm_fifo_t * f)
+{
+ return f->n_subscribers;
+}
+
+/**
+ * Check if fifo has out-of-order data
+ *
+ * @param f fifo
+ * @return 1 if fifo has ooo data, 0 otherwise
+ */
static inline u8
svm_fifo_has_ooo_data (svm_fifo_t * f)
{
return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
}
+static inline ooo_segment_t *
+svm_fifo_newest_ooo_segment (svm_fifo_t * f)
+{
+ if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
+ return 0;
+ return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
+}
+
+static inline void
+svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
+{
+ f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
+}
+
+static inline u32
+ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s)
+{
+ u32 tail;
+ /* load-relaxed: producer owned index */
+ tail = f->tail;
+
+ return f_distance_to (f, s->start, tail);
+}
+
+static inline u32
+ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
+{
+ return s->length;
+}
+
+/**
+ * Check if fifo has io event
+ *
+ * @param f fifo
+ * @return 1 if fifo has event, 0 otherwise
+ */
+static inline int
+svm_fifo_has_event (svm_fifo_t * f)
+{
+ return f->has_event;
+}
+
/**
- * Sets fifo event flag.
+ * Set fifo event flag.
*
- * @return 1 if flag was not set.
+ * Forces release semantics.
+ *
+ * @param f fifo
+ * @return 1 if flag was not set, 0 otherwise
*/
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;
+ return !clib_atomic_swap_rel_n (&f->has_event, 1);
}
/**
- * Unsets fifo event flag.
+ * Unset fifo event flag.
+ *
+ * Forces acquire semantics
+ *
+ * @param f fifo
*/
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);
+ clib_atomic_swap_acq_n (&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);
+/**
+ * Set specific want notification flag
+ *
+ * For list of flags see @ref svm_fifo_deq_ntf_t
+ *
+ * @param f fifo
+ * @param ntf_type type of notification requested
+ */
+static inline void
+svm_fifo_add_want_deq_ntf (svm_fifo_t * f, u8 ntf_type)
+{
+ f->want_deq_ntf |= ntf_type;
+}
-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);
+/**
+ * Clear specific want notification flag
+ *
+ * For list of flags see @ref svm_fifo_ntf_t
+ *
+ * @param f fifo
+ * @param ntf_type type of notification to be cleared
+ */
+static inline void
+svm_fifo_del_want_deq_ntf (svm_fifo_t * f, u8 ntf_type)
+{
+ f->want_deq_ntf &= ~ntf_type;
+}
-always_inline ooo_segment_t *
-svm_fifo_newest_ooo_segment (svm_fifo_t * f)
+/**
+ * Clear the want notification flag and set has notification
+ *
+ * Should be used after enqueuing an event. This clears the
+ * SVM_FIFO_WANT_NOTIF flag but it does not clear
+ * SVM_FIFO_WANT_NOTIF_IF_FULL. If the latter was set, has_ntf is
+ * set to avoid enqueueing events for for all dequeue operations until
+ * it is manually cleared.
+ *
+ * @param f fifo
+ */
+static inline void
+svm_fifo_clear_deq_ntf (svm_fifo_t * f)
{
- return f->ooo_segments + f->ooos_newest;
+ /* Set the flag if want_notif_if_full was the only ntf requested */
+ f->has_deq_ntf = f->want_deq_ntf == SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL;
+ svm_fifo_del_want_deq_ntf (f, SVM_FIFO_WANT_DEQ_NOTIF);
}
-always_inline u32
-ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s)
+/**
+ * Clear has notification flag
+ *
+ * The fifo generates only one event per SVM_FIFO_WANT_NOTIF_IF_FULL
+ * request and sets has_ntf. To received new events the flag must be
+ * cleared using this function.
+ *
+ * @param f fifo
+ */
+static inline void
+svm_fifo_reset_has_deq_ntf (svm_fifo_t * f)
{
- return ((f->nitems + s->fifo_position - f->tail) % f->nitems);
+ f->has_deq_ntf = 0;
}
-always_inline u32
-ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s)
+/**
+ * Check if fifo needs dequeue notification
+ *
+ * Determines based on notification request flags and state of the fifo if
+ * an event should be generated.
+ *
+ * @param f fifo
+ * @param n_last_deq number of bytes last dequeued
+ * @return 1 if event should be generated, 0 otherwise
+ */
+static inline u8
+svm_fifo_needs_deq_ntf (svm_fifo_t * f, u32 n_last_deq)
{
- return ((f->nitems + s->fifo_position + s->length - f->tail) % f->nitems);
+ u8 want_ntf = f->want_deq_ntf;
+
+ if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_DEQ_NOTIF))
+ return 0;
+ else if (want_ntf & SVM_FIFO_WANT_DEQ_NOTIF)
+ return 1;
+ if (want_ntf & SVM_FIFO_WANT_DEQ_NOTIF_IF_FULL)
+ {
+ u32 max_deq = svm_fifo_max_dequeue_cons (f);
+ u32 nitems = f->nitems;
+ if (!f->has_deq_ntf && max_deq < nitems
+ && max_deq + n_last_deq >= nitems)
+ return 1;
+ }
+ if (want_ntf & SVM_FIFO_WANT_DEQ_NOTIF_IF_EMPTY)
+ {
+ if (!f->has_deq_ntf && svm_fifo_is_empty (f))
+ return 1;
+ }
+ return 0;
}
#endif /* __included_ssvm_fifo_h__ */
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