git.sur5r.net Git - freertos/blob - FreeRTOS/Source/portable/MemMang/heap_4.c

   1 /*\r
   2  * FreeRTOS Kernel V10.3.0\r
   3  * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.\r
   4  *\r
   5  * Permission is hereby granted, free of charge, to any person obtaining a copy of\r
   6  * this software and associated documentation files (the "Software"), to deal in\r
   7  * the Software without restriction, including without limitation the rights to\r
   8  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of\r
   9  * the Software, and to permit persons to whom the Software is furnished to do so,\r
  10  * subject to the following conditions:\r
  11  *\r
  12  * The above copyright notice and this permission notice shall be included in all\r
  13  * copies or substantial portions of the Software.\r
  14  *\r
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\r
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS\r
  17  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR\r
  18  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER\r
  19  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN\r
  20  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
  21  *\r
  22  * http://www.FreeRTOS.org\r
  23  * http://aws.amazon.com/freertos\r
  24  *\r
  25  * 1 tab == 4 spaces!\r
  26  */\r
  27 \r
  28 /*\r
  29  * A sample implementation of pvPortMalloc() and vPortFree() that combines\r
  30  * (coalescences) adjacent memory blocks as they are freed, and in so doing\r
  31  * limits memory fragmentation.\r
  32  *\r
  33  * See heap_1.c, heap_2.c and heap_3.c for alternative implementations, and the\r
  34  * memory management pages of http://www.FreeRTOS.org for more information.\r
  35  */\r
  36 #include <stdlib.h>\r
  37 \r
  38 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining\r
  39 all the API functions to use the MPU wrappers.  That should only be done when\r
  40 task.h is included from an application file. */\r
  41 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE\r
  42 \r
  43 #include "FreeRTOS.h"\r
  44 #include "task.h"\r
  45 \r
  46 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE\r
  47 \r
  48 #if( configSUPPORT_DYNAMIC_ALLOCATION == 0 )\r
  49         #error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0\r
  50 #endif\r
  51 \r
  52 /* Block sizes must not get too small. */\r
  53 #define heapMINIMUM_BLOCK_SIZE  ( ( size_t ) ( xHeapStructSize << 1 ) )\r
  54 \r
  55 /* Assumes 8bit bytes! */\r
  56 #define heapBITS_PER_BYTE               ( ( size_t ) 8 )\r
  57 \r
  58 /* Allocate the memory for the heap. */\r
  59 #if( configAPPLICATION_ALLOCATED_HEAP == 1 )\r
  60         /* The application writer has already defined the array used for the RTOS\r
  61         heap - probably so it can be placed in a special segment or address. */\r
  62         extern uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];\r
  63 #else\r
  64         static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];\r
  65 #endif /* configAPPLICATION_ALLOCATED_HEAP */\r
  66 \r
  67 /* Define the linked list structure.  This is used to link free blocks in order\r
  68 of their memory address. */\r
  69 typedef struct A_BLOCK_LINK\r
  70 {\r
  71         struct A_BLOCK_LINK *pxNextFreeBlock;   /*<< The next free block in the list. */\r
  72         size_t xBlockSize;                                              /*<< The size of the free block. */\r
  73 } BlockLink_t;\r
  74 \r
  75 /*-----------------------------------------------------------*/\r
  76 \r
  77 /*\r
  78  * Inserts a block of memory that is being freed into the correct position in\r
  79  * the list of free memory blocks.  The block being freed will be merged with\r
  80  * the block in front it and/or the block behind it if the memory blocks are\r
  81  * adjacent to each other.\r
  82  */\r
  83 static void prvInsertBlockIntoFreeList( BlockLink_t *pxBlockToInsert );\r
  84 \r
  85 /*\r
  86  * Called automatically to setup the required heap structures the first time\r
  87  * pvPortMalloc() is called.\r
  88  */\r
  89 static void prvHeapInit( void );\r
  90 \r
  91 /*-----------------------------------------------------------*/\r
  92 \r
  93 /* The size of the structure placed at the beginning of each allocated memory\r
  94 block must by correctly byte aligned. */\r
  95 static const size_t xHeapStructSize     = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK );\r
  96 \r
  97 /* Create a couple of list links to mark the start and end of the list. */\r
  98 static BlockLink_t xStart, *pxEnd = NULL;\r
  99 \r
 100 /* Keeps track of the number of calls to allocate and free memory as well as the\r
 101 number of free bytes remaining, but says nothing about fragmentation. */\r
 102 static size_t xFreeBytesRemaining = 0U;\r
 103 static size_t xMinimumEverFreeBytesRemaining = 0U;\r
 104 static size_t xNumberOfSuccessfulAllocations = 0;\r
 105 static size_t xNumberOfSuccessfulFrees = 0;\r
 106 \r
 107 /* Gets set to the top bit of an size_t type.  When this bit in the xBlockSize\r
 108 member of an BlockLink_t structure is set then the block belongs to the\r
 109 application.  When the bit is free the block is still part of the free heap\r
 110 space. */\r
 111 static size_t xBlockAllocatedBit = 0;\r
 112 \r
 113 /*-----------------------------------------------------------*/\r
 114 \r
 115 void *pvPortMalloc( size_t xWantedSize )\r
 116 {\r
 117 BlockLink_t *pxBlock, *pxPreviousBlock, *pxNewBlockLink;\r
 118 void *pvReturn = NULL;\r
 119 \r
 120         vTaskSuspendAll();\r
 121         {\r
 122                 /* If this is the first call to malloc then the heap will require\r
 123                 initialisation to setup the list of free blocks. */\r
 124                 if( pxEnd == NULL )\r
 125                 {\r
 126                         prvHeapInit();\r
 127                 }\r
 128                 else\r
 129                 {\r
 130                         mtCOVERAGE_TEST_MARKER();\r
 131                 }\r
 132 \r
 133                 /* Check the requested block size is not so large that the top bit is\r
 134                 set.  The top bit of the block size member of the BlockLink_t structure\r
 135                 is used to determine who owns the block - the application or the\r
 136                 kernel, so it must be free. */\r
 137                 if( ( xWantedSize & xBlockAllocatedBit ) == 0 )\r
 138                 {\r
 139                         /* The wanted size is increased so it can contain a BlockLink_t\r
 140                         structure in addition to the requested amount of bytes. */\r
 141                         if( xWantedSize > 0 )\r
 142                         {\r
 143                                 xWantedSize += xHeapStructSize;\r
 144 \r
 145                                 /* Ensure that blocks are always aligned to the required number\r
 146                                 of bytes. */\r
 147                                 if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 )\r
 148                                 {\r
 149                                         /* Byte alignment required. */\r
 150                                         xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );\r
 151                                         configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 );\r
 152                                 }\r
 153                                 else\r
 154                                 {\r
 155                                         mtCOVERAGE_TEST_MARKER();\r
 156                                 }\r
 157                         }\r
 158                         else\r
 159                         {\r
 160                                 mtCOVERAGE_TEST_MARKER();\r
 161                         }\r
 162 \r
 163                         if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) )\r
 164                         {\r
 165                                 /* Traverse the list from the start     (lowest address) block until\r
 166                                 one     of adequate size is found. */\r
 167                                 pxPreviousBlock = &xStart;\r
 168                                 pxBlock = xStart.pxNextFreeBlock;\r
 169                                 while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) )\r
 170                                 {\r
 171                                         pxPreviousBlock = pxBlock;\r
 172                                         pxBlock = pxBlock->pxNextFreeBlock;\r
 173                                 }\r
 174 \r
 175                                 /* If the end marker was reached then a block of adequate size\r
 176                                 was     not found. */\r
 177                                 if( pxBlock != pxEnd )\r
 178                                 {\r
 179                                         /* Return the memory space pointed to - jumping over the\r
 180                                         BlockLink_t structure at its start. */\r
 181                                         pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize );\r
 182 \r
 183                                         /* This block is being returned for use so must be taken out\r
 184                                         of the list of free blocks. */\r
 185                                         pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;\r
 186 \r
 187                                         /* If the block is larger than required it can be split into\r
 188                                         two. */\r
 189                                         if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )\r
 190                                         {\r
 191                                                 /* This block is to be split into two.  Create a new\r
 192                                                 block following the number of bytes requested. The void\r
 193                                                 cast is used to prevent byte alignment warnings from the\r
 194                                                 compiler. */\r
 195                                                 pxNewBlockLink = ( void * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize );\r
 196                                                 configASSERT( ( ( ( size_t ) pxNewBlockLink ) & portBYTE_ALIGNMENT_MASK ) == 0 );\r
 197 \r
 198                                                 /* Calculate the sizes of two blocks split from the\r
 199                                                 single block. */\r
 200                                                 pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;\r
 201                                                 pxBlock->xBlockSize = xWantedSize;\r
 202 \r
 203                                                 /* Insert the new block into the list of free blocks. */\r
 204                                                 prvInsertBlockIntoFreeList( pxNewBlockLink );\r
 205                                         }\r
 206                                         else\r
 207                                         {\r
 208                                                 mtCOVERAGE_TEST_MARKER();\r
 209                                         }\r
 210 \r
 211                                         xFreeBytesRemaining -= pxBlock->xBlockSize;\r
 212 \r
 213                                         if( xFreeBytesRemaining < xMinimumEverFreeBytesRemaining )\r
 214                                         {\r
 215                                                 xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;\r
 216                                         }\r
 217                                         else\r
 218                                         {\r
 219                                                 mtCOVERAGE_TEST_MARKER();\r
 220                                         }\r
 221 \r
 222                                         /* The block is being returned - it is allocated and owned\r
 223                                         by the application and has no "next" block. */\r
 224                                         pxBlock->xBlockSize |= xBlockAllocatedBit;\r
 225                                         pxBlock->pxNextFreeBlock = NULL;\r
 226                                         xNumberOfSuccessfulAllocations++;\r
 227                                 }\r
 228                                 else\r
 229                                 {\r
 230                                         mtCOVERAGE_TEST_MARKER();\r
 231                                 }\r
 232                         }\r
 233                         else\r
 234                         {\r
 235                                 mtCOVERAGE_TEST_MARKER();\r
 236                         }\r
 237                 }\r
 238                 else\r
 239                 {\r
 240                         mtCOVERAGE_TEST_MARKER();\r
 241                 }\r
 242 \r
 243                 traceMALLOC( pvReturn, xWantedSize );\r
 244         }\r
 245         ( void ) xTaskResumeAll();\r
 246 \r
 247         #if( configUSE_MALLOC_FAILED_HOOK == 1 )\r
 248         {\r
 249                 if( pvReturn == NULL )\r
 250                 {\r
 251                         extern void vApplicationMallocFailedHook( void );\r
 252                         vApplicationMallocFailedHook();\r
 253                 }\r
 254                 else\r
 255                 {\r
 256                         mtCOVERAGE_TEST_MARKER();\r
 257                 }\r
 258         }\r
 259         #endif\r
 260 \r
 261         configASSERT( ( ( ( size_t ) pvReturn ) & ( size_t ) portBYTE_ALIGNMENT_MASK ) == 0 );\r
 262         return pvReturn;\r
 263 }\r
 264 /*-----------------------------------------------------------*/\r
 265 \r
 266 void vPortFree( void *pv )\r
 267 {\r
 268 uint8_t *puc = ( uint8_t * ) pv;\r
 269 BlockLink_t *pxLink;\r
 270 \r
 271         if( pv != NULL )\r
 272         {\r
 273                 /* The memory being freed will have an BlockLink_t structure immediately\r
 274                 before it. */\r
 275                 puc -= xHeapStructSize;\r
 276 \r
 277                 /* This casting is to keep the compiler from issuing warnings. */\r
 278                 pxLink = ( void * ) puc;\r
 279 \r
 280                 /* Check the block is actually allocated. */\r
 281                 configASSERT( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 );\r
 282                 configASSERT( pxLink->pxNextFreeBlock == NULL );\r
 283 \r
 284                 if( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 )\r
 285                 {\r
 286                         if( pxLink->pxNextFreeBlock == NULL )\r
 287                         {\r
 288                                 /* The block is being returned to the heap - it is no longer\r
 289                                 allocated. */\r
 290                                 pxLink->xBlockSize &= ~xBlockAllocatedBit;\r
 291 \r
 292                                 vTaskSuspendAll();\r
 293                                 {\r
 294                                         /* Add this block to the list of free blocks. */\r
 295                                         xFreeBytesRemaining += pxLink->xBlockSize;\r
 296                                         traceFREE( pv, pxLink->xBlockSize );\r
 297                                         prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) );\r
 298                                         xNumberOfSuccessfulFrees++;\r
 299                                 }\r
 300                                 ( void ) xTaskResumeAll();\r
 301                         }\r
 302                         else\r
 303                         {\r
 304                                 mtCOVERAGE_TEST_MARKER();\r
 305                         }\r
 306                 }\r
 307                 else\r
 308                 {\r
 309                         mtCOVERAGE_TEST_MARKER();\r
 310                 }\r
 311         }\r
 312 }\r
 313 /*-----------------------------------------------------------*/\r
 314 \r
 315 size_t xPortGetFreeHeapSize( void )\r
 316 {\r
 317         return xFreeBytesRemaining;\r
 318 }\r
 319 /*-----------------------------------------------------------*/\r
 320 \r
 321 size_t xPortGetMinimumEverFreeHeapSize( void )\r
 322 {\r
 323         return xMinimumEverFreeBytesRemaining;\r
 324 }\r
 325 /*-----------------------------------------------------------*/\r
 326 \r
 327 void vPortInitialiseBlocks( void )\r
 328 {\r
 329         /* This just exists to keep the linker quiet. */\r
 330 }\r
 331 /*-----------------------------------------------------------*/\r
 332 \r
 333 static void prvHeapInit( void )\r
 334 {\r
 335 BlockLink_t *pxFirstFreeBlock;\r
 336 uint8_t *pucAlignedHeap;\r
 337 size_t uxAddress;\r
 338 size_t xTotalHeapSize = configTOTAL_HEAP_SIZE;\r
 339 \r
 340         /* Ensure the heap starts on a correctly aligned boundary. */\r
 341         uxAddress = ( size_t ) ucHeap;\r
 342 \r
 343         if( ( uxAddress & portBYTE_ALIGNMENT_MASK ) != 0 )\r
 344         {\r
 345                 uxAddress += ( portBYTE_ALIGNMENT - 1 );\r
 346                 uxAddress &= ~( ( size_t ) portBYTE_ALIGNMENT_MASK );\r
 347                 xTotalHeapSize -= uxAddress - ( size_t ) ucHeap;\r
 348         }\r
 349 \r
 350         pucAlignedHeap = ( uint8_t * ) uxAddress;\r
 351 \r
 352         /* xStart is used to hold a pointer to the first item in the list of free\r
 353         blocks.  The void cast is used to prevent compiler warnings. */\r
 354         xStart.pxNextFreeBlock = ( void * ) pucAlignedHeap;\r
 355         xStart.xBlockSize = ( size_t ) 0;\r
 356 \r
 357         /* pxEnd is used to mark the end of the list of free blocks and is inserted\r
 358         at the end of the heap space. */\r
 359         uxAddress = ( ( size_t ) pucAlignedHeap ) + xTotalHeapSize;\r
 360         uxAddress -= xHeapStructSize;\r
 361         uxAddress &= ~( ( size_t ) portBYTE_ALIGNMENT_MASK );\r
 362         pxEnd = ( void * ) uxAddress;\r
 363         pxEnd->xBlockSize = 0;\r
 364         pxEnd->pxNextFreeBlock = NULL;\r
 365 \r
 366         /* To start with there is a single free block that is sized to take up the\r
 367         entire heap space, minus the space taken by pxEnd. */\r
 368         pxFirstFreeBlock = ( void * ) pucAlignedHeap;\r
 369         pxFirstFreeBlock->xBlockSize = uxAddress - ( size_t ) pxFirstFreeBlock;\r
 370         pxFirstFreeBlock->pxNextFreeBlock = pxEnd;\r
 371 \r
 372         /* Only one block exists - and it covers the entire usable heap space. */\r
 373         xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;\r
 374         xFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;\r
 375 \r
 376         /* Work out the position of the top bit in a size_t variable. */\r
 377         xBlockAllocatedBit = ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 );\r
 378 }\r
 379 /*-----------------------------------------------------------*/\r
 380 \r
 381 static void prvInsertBlockIntoFreeList( BlockLink_t *pxBlockToInsert )\r
 382 {\r
 383 BlockLink_t *pxIterator;\r
 384 uint8_t *puc;\r
 385 \r
 386         /* Iterate through the list until a block is found that has a higher address\r
 387         than the block being inserted. */\r
 388         for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock )\r
 389         {\r
 390                 /* Nothing to do here, just iterate to the right position. */\r
 391         }\r
 392 \r
 393         /* Do the block being inserted, and the block it is being inserted after\r
 394         make a contiguous block of memory? */\r
 395         puc = ( uint8_t * ) pxIterator;\r
 396         if( ( puc + pxIterator->xBlockSize ) == ( uint8_t * ) pxBlockToInsert )\r
 397         {\r
 398                 pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;\r
 399                 pxBlockToInsert = pxIterator;\r
 400         }\r
 401         else\r
 402         {\r
 403                 mtCOVERAGE_TEST_MARKER();\r
 404         }\r
 405 \r
 406         /* Do the block being inserted, and the block it is being inserted before\r
 407         make a contiguous block of memory? */\r
 408         puc = ( uint8_t * ) pxBlockToInsert;\r
 409         if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock )\r
 410         {\r
 411                 if( pxIterator->pxNextFreeBlock != pxEnd )\r
 412                 {\r
 413                         /* Form one big block from the two blocks. */\r
 414                         pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;\r
 415                         pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;\r
 416                 }\r
 417                 else\r
 418                 {\r
 419                         pxBlockToInsert->pxNextFreeBlock = pxEnd;\r
 420                 }\r
 421         }\r
 422         else\r
 423         {\r
 424                 pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;\r
 425         }\r
 426 \r
 427         /* If the block being inserted plugged a gab, so was merged with the block\r
 428         before and the block after, then it's pxNextFreeBlock pointer will have\r
 429         already been set, and should not be set here as that would make it point\r
 430         to itself. */\r
 431         if( pxIterator != pxBlockToInsert )\r
 432         {\r
 433                 pxIterator->pxNextFreeBlock = pxBlockToInsert;\r
 434         }\r
 435         else\r
 436         {\r
 437                 mtCOVERAGE_TEST_MARKER();\r
 438         }\r
 439 }\r
 440 /*-----------------------------------------------------------*/\r
 441 \r
 442 void vPortGetHeapStats( HeapStats_t *pxHeapStats )\r
 443 {\r
 444 BlockLink_t *pxBlock;\r
 445 size_t xBlocks = 0, xMaxSize = 0, xMinSize = portMAX_DELAY; /* portMAX_DELAY used as a portable way of getting the maximum value. */\r
 446 \r
 447         vTaskSuspendAll();\r
 448         {\r
 449                 pxBlock = xStart.pxNextFreeBlock;\r
 450 \r
 451                 /* pxBlock will be NULL if the heap has not been initialised.  The heap\r
 452                 is initialised automatically when the first allocation is made. */\r
 453                 if( pxBlock != NULL )\r
 454                 {\r
 455                         do\r
 456                         {\r
 457                                 /* Increment the number of blocks and record the largest block seen\r
 458                                 so far. */\r
 459                                 xBlocks++;\r
 460 \r
 461                                 if( pxBlock->xBlockSize > xMaxSize )\r
 462                                 {\r
 463                                         xMaxSize = pxBlock->xBlockSize;\r
 464                                 }\r
 465 \r
 466                                 if( pxBlock->xBlockSize < xMinSize )\r
 467                                 {\r
 468                                         xMinSize = pxBlock->xBlockSize;\r
 469                                 }\r
 470 \r
 471                                 /* Move to the next block in the chain until the last block is\r
 472                                 reached. */\r
 473                                 pxBlock = pxBlock->pxNextFreeBlock;\r
 474                         } while( pxBlock != pxEnd );\r
 475                 }\r
 476         }\r
 477         xTaskResumeAll();\r
 478 \r
 479         pxHeapStats->xSizeOfLargestFreeBlockInBytes = xMaxSize;\r
 480         pxHeapStats->xSizeOfSmallestFreeBlockInBytes = xMinSize;\r
 481         pxHeapStats->xNumberOfFreeBlocks = xBlocks;\r
 482 \r
 483         taskENTER_CRITICAL();\r
 484         {\r
 485                 pxHeapStats->xAvailableHeapSpaceInBytes = xFreeBytesRemaining;\r
 486                 pxHeapStats->xNumberOfSuccessfulAllocations = xNumberOfSuccessfulAllocations;\r
 487                 pxHeapStats->xNumberOfSuccessfulFrees = xNumberOfSuccessfulFrees;\r
 488                 pxHeapStats->xMinimumEverFreeBytesRemaining = xMinimumEverFreeBytesRemaining;\r
 489         }\r
 490         taskEXIT_CRITICAL();\r
 491 }\r
 492 \r