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     CLIB_CACHE_LINE_ALIGN_MARK (data);
  79 } svm_fifo_t;
  80
  81 #if SVM_FIFO_TRACE
  82 #define svm_fifo_trace_add(_f, _s, _l, _t)              \
  83 {                                                       \
  84   svm_fifo_trace_elem_t *trace_elt;                     \
  85   vec_add2(_f->trace, trace_elt, 1);                    \
  86   trace_elt->offset = _s;                               \
  87   trace_elt->len = _l;                                  \
  88   trace_elt->action = _t;                               \
  89 }
  90 #else
  91 #define svm_fifo_trace_add(_f, _s, _l, _t)
  92 #endif
  93
  94 u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
  95 u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
  96
  97 static inline u32
  98 svm_fifo_max_dequeue (svm_fifo_t * f)
  99 {
 100   return f->cursize;
 101 }
 102
 103 static inline u32
 104 svm_fifo_max_enqueue (svm_fifo_t * f)
 105 {
 106   return f->nitems - svm_fifo_max_dequeue (f);
 107 }
 108
 109 static inline u8
 110 svm_fifo_has_ooo_data (svm_fifo_t * f)
 111 {
 112   return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
 113 }
 114
 115 /**
 116  * Sets fifo event flag.
 117  *
 118  * @return 1 if flag was not set.
 119  */
 120 always_inline u8
 121 svm_fifo_set_event (svm_fifo_t * f)
 122 {
 123   /* Probably doesn't need to be atomic. Still, better avoid surprises */
 124   return __sync_lock_test_and_set (&f->has_event, 1) == 0;
 125 }
 126
 127 /**
 128  * Unsets fifo event flag.
 129  */
 130 always_inline void
 131 svm_fifo_unset_event (svm_fifo_t * f)
 132 {
 133   /* Probably doesn't need to be atomic. Still, better avoid surprises */
 134   __sync_lock_release (&f->has_event);
 135 }
 136
 137 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
 138 void svm_fifo_free (svm_fifo_t * f);
 139
 140 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
 141                              u8 * copy_from_here);
 142 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
 143                                   u32 required_bytes, u8 * copy_from_here);
 144 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
 145
 146 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
 147 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
 148 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
 149 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
 150 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
 151
 152 format_function_t format_svm_fifo;
 153
 154 always_inline ooo_segment_t *
 155 svm_fifo_newest_ooo_segment (svm_fifo_t * f)
 156 {
 157   if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
 158     return 0;
 159   return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
 160 }
 161
 162 always_inline void
 163 svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
 164 {
 165   f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
 166 }
 167
 168 always_inline u32
 169 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos)
 170 {
 171   /* Ambiguous. Assumption is that ooo segments don't touch tail */
 172   if (PREDICT_FALSE (pos == f->tail && f->tail == f->head))
 173     return f->nitems;
 174
 175   return (((f->nitems + pos) - f->tail) % f->nitems);
 176 }
 177
 178 always_inline u32
 179 ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos)
 180 {
 181   return (((f->nitems + f->tail) - pos) % f->nitems);
 182 }
 183
 184 always_inline u32
 185 ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s)
 186 {
 187   return ooo_segment_distance_from_tail (f, s->start);
 188 }
 189
 190 always_inline u32
 191 ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s)
 192 {
 193   return ooo_segment_distance_from_tail (f, s->start) + s->length;
 194 }
 195
 196 always_inline u32
 197 ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
 198 {
 199   return s->length;
 200 }
 201
 202 always_inline ooo_segment_t *
 203 ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
 204 {
 205   if (s->prev == OOO_SEGMENT_INVALID_INDEX)
 206     return 0;
 207   return pool_elt_at_index (f->ooo_segments, s->prev);
 208 }
 209
 210 always_inline ooo_segment_t *
 211 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
 212 {
 213   if (s->next == OOO_SEGMENT_INVALID_INDEX)
 214     return 0;
 215   return pool_elt_at_index (f->ooo_segments, s->next);
 216 }
 217
 218 #endif /* __included_ssvm_fifo_h__ */
 219
 220 /*
 221  * fd.io coding-style-patch-verification: ON
 222  *
 223  * Local Variables:
 224  * eval: (c-set-style "gnu")
 225  * End:
 226  */