/* * 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: * * 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/pool.h> #include <vppinfra/format.h> #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 start; /**< Start of segment, normalized*/ u32 length; /**< Length of segment */ } ooo_segment_t; #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 { u32 offset; u32 len; u32 action; } svm_fifo_trace_elem_t; 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 */ u8 data[0]; /**< start of chunk data */ } svm_fifo_chunk_t; 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; 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 */ svm_fifo_chunk_t *new_chunks; /**< chunks yet to be added to list */ rb_tree_t chunk_lookup; /**< rbtree for chunk lookup */ u8 flags; /**< fifo flags */ u8 slice_index; /**< segment slice for fifo */ 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 */ u32 size_decrement; /**< bytes to remove from fifo */ 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 } svm_fifo_t; typedef enum { 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 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) { 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) { 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) { 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; } /** * Set fifo event flag. * * 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) { return !clib_atomic_swap_rel_n (&f->has_event, 1); } /** * Unset fifo event flag. * * Forces acquire semantics * * @param f fifo */ always_inline void svm_fifo_unset_event (svm_fifo_t * f) { clib_atomic_swap_acq_n (&f->has_event, 0); } /** * 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; } /** * 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; } /** * 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) { /* 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); } /** * 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) { f->has_deq_ntf = 0; } /** * 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) { 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__ */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */