src/svm/svm_fifo.h

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15 #ifndef __included_ssvm_fifo_h__
  16 #define __included_ssvm_fifo_h__
  17
  18 #include <vppinfra/clib.h>
  19 #include <vppinfra/vec.h>
  20 #include <vppinfra/mheap.h>
  21 #include <vppinfra/heap.h>
  22 #include <vppinfra/pool.h>
  23 #include <vppinfra/format.h>
  24 #include <pthread.h>
  25
  26 /** Out-of-order segment */
  27 typedef struct
  28 {
  29   u32 next;     /**< Next linked-list element pool index */
  30   u32 prev;     /**< Previous linked-list element pool index */
  31
  32   u32 start;    /**< Start of segment, normalized*/
  33   u32 length;   /**< Length of segment */
  34 } ooo_segment_t;
  35
  36 format_function_t format_ooo_segment;
  37 format_function_t format_ooo_list;
  38
  39 #define SVM_FIFO_TRACE (0)
  40 #define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
  41
  42 typedef struct
  43 {
  44   u32 offset;
  45   u32 len;
  46   u32 action;
  47 } svm_fifo_trace_elem_t;
  48
  49 typedef struct _svm_fifo
  50 {
  51   volatile u32 cursize;         /**< current fifo size */
  52   u32 nitems;
  53     CLIB_CACHE_LINE_ALIGN_MARK (end_cursize);
  54
  55   volatile u32 has_event;       /**< non-zero if deq event exists */
  56
  57   /* Backpointers */
  58   u32 master_session_index;
  59   u32 client_session_index;
  60   u8 master_thread_index;
  61   u8 client_thread_index;
  62   u32 segment_manager;
  63     CLIB_CACHE_LINE_ALIGN_MARK (end_shared);
  64   u32 head;
  65     CLIB_CACHE_LINE_ALIGN_MARK (end_consumer);
  66
  67   /* producer */
  68   u32 tail;
  69
  70   ooo_segment_t *ooo_segments;  /**< Pool of ooo segments */
  71   u32 ooos_list_head;           /**< Head of out-of-order linked-list */
  72   u32 ooos_newest;              /**< Last segment to have been updated */
  73   struct _svm_fifo *next;       /**< next in freelist/active chain */
  74   struct _svm_fifo *prev;       /**< prev in active chain */
  75 #if SVM_FIFO_TRACE
  76   svm_fifo_trace_elem_t *trace;
  77 #endif
  78   u32 freelist_index;           /**< aka log2(allocated_size) - const. */
  79   i8 refcnt;                    /**< reference count  */
  80     CLIB_CACHE_LINE_ALIGN_MARK (data);
  81 } svm_fifo_t;
  82
  83 #if SVM_FIFO_TRACE
  84 #define svm_fifo_trace_add(_f, _s, _l, _t)              \
  85 {                                                       \
  86   svm_fifo_trace_elem_t *trace_elt;                     \
  87   vec_add2(_f->trace, trace_elt, 1);                    \
  88   trace_elt->offset = _s;                               \
  89   trace_elt->len = _l;                                  \
  90   trace_elt->action = _t;                               \
  91 }
  92 #else
  93 #define svm_fifo_trace_add(_f, _s, _l, _t)
  94 #endif
  95
  96 u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
  97 u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
  98
  99 static inline u32
 100 svm_fifo_max_dequeue (svm_fifo_t * f)
 101 {
 102   return f->cursize;
 103 }
 104
 105 static inline u32
 106 svm_fifo_max_enqueue (svm_fifo_t * f)
 107 {
 108   return f->nitems - svm_fifo_max_dequeue (f);
 109 }
 110
 111 static inline u8
 112 svm_fifo_has_ooo_data (svm_fifo_t * f)
 113 {
 114   return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
 115 }
 116
 117 /**
 118  * Sets fifo event flag.
 119  *
 120  * @return 1 if flag was not set.
 121  */
 122 always_inline u8
 123 svm_fifo_set_event (svm_fifo_t * f)
 124 {
 125   /* Probably doesn't need to be atomic. Still, better avoid surprises */
 126   return __sync_lock_test_and_set (&f->has_event, 1) == 0;
 127 }
 128
 129 /**
 130  * Unsets fifo event flag.
 131  */
 132 always_inline void
 133 svm_fifo_unset_event (svm_fifo_t * f)
 134 {
 135   /* Probably doesn't need to be atomic. Still, better avoid surprises */
 136   __sync_lock_release (&f->has_event);
 137 }
 138
 139 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
 140 void svm_fifo_free (svm_fifo_t * f);
 141
 142 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
 143                              u8 * copy_from_here);
 144 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
 145                                   u32 required_bytes, u8 * copy_from_here);
 146 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
 147
 148 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
 149 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
 150 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
 151 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
 152 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
 153
 154 format_function_t format_svm_fifo;
 155
 156 always_inline ooo_segment_t *
 157 svm_fifo_newest_ooo_segment (svm_fifo_t * f)
 158 {
 159   if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
 160     return 0;
 161   return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
 162 }
 163
 164 always_inline void
 165 svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
 166 {
 167   f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
 168 }
 169
 170 always_inline u32
 171 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos)
 172 {
 173   /* Ambiguous. Assumption is that ooo segments don't touch tail */
 174   if (PREDICT_FALSE (pos == f->tail && f->tail == f->head))
 175     return f->nitems;
 176
 177   return (((f->nitems + pos) - f->tail) % f->nitems);
 178 }
 179
 180 always_inline u32
 181 ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos)
 182 {
 183   return (((f->nitems + f->tail) - pos) % f->nitems);
 184 }
 185
 186 always_inline u32
 187 ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s)
 188 {
 189   return ooo_segment_distance_from_tail (f, s->start);
 190 }
 191
 192 always_inline u32
 193 ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s)
 194 {
 195   return ooo_segment_distance_from_tail (f, s->start) + s->length;
 196 }
 197
 198 always_inline u32
 199 ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
 200 {
 201   return s->length;
 202 }
 203
 204 always_inline ooo_segment_t *
 205 ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
 206 {
 207   if (s->prev == OOO_SEGMENT_INVALID_INDEX)
 208     return 0;
 209   return pool_elt_at_index (f->ooo_segments, s->prev);
 210 }
 211
 212 always_inline ooo_segment_t *
 213 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
 214 {
 215   if (s->next == OOO_SEGMENT_INVALID_INDEX)
 216     return 0;
 217   return pool_elt_at_index (f->ooo_segments, s->next);
 218 }
 219
 220 #endif /* __included_ssvm_fifo_h__ */
 221
 222 /*
 223  * fd.io coding-style-patch-verification: ON
 224  *
 225  * Local Variables:
 226  * eval: (c-set-style "gnu")
 227  * End:
 228  */