le_mem.h

    1 /**
    2  * @page c_memory Dynamic Memory Allocation API
    3  *
    4  *
    5  * @ref le_mem.h "API Reference"
    6  *
    7  * <HR>
    8  *
    9  * Dynamic memory allocation (especially deallocation) using the C runtime heap, through
   10  * malloc, free, strdup, calloc, realloc, etc. can result in performance degradation and out-of-memory
   11  * conditions.
   12  *
   13  * This is due to fragmentation of the heap. The degraded performance and exhausted memory result from indirect interactions
   14  * within the heap between unrelated application code. These issues are non-deterministic,
   15  * and can be very difficult to rectify.
   16  *
   17  * Memory Pools offer a powerful solution.  They trade-off a deterministic amount of
   18  * memory for
   19  *  - deterministic behaviour,
   20  *  - O(1) allocation and release performance, and
   21  *  - built-in memory allocation tracking.
   22  *
   23  * And it brings the power of @b destructors to C!
   24  *
   25  * @todo
   26  *     Do we need to add a "resettable heap" option to the memory management tool kit?
   27  *
   28  *
   29  * @section mem_overview Overview
   30  *
   31  * The most basic usage involves:
   32  *  - Creating a pool (usually done once at process start-up)
   33  *  - Allocating objects (memory blocks) from a pool
   34  *  - Releasing objects back to their pool.
   35  *
   36  * Pools generally can't be deleted.  You create them when your process
   37  * starts-up, and use them until your process terminates. It's up to the OS to clean-up the memory
   38  * pools, along with everything else your process is using, when your process terminates.  (Although,
   39  * if you find yourself really needing to delete pools, @ref mem_sub_pools could offer you a solution.)
   40  *
   41  * Pools also support the following advanced features:
   42  *  - reference counting
   43  *  - destructors
   44  *  - statistics
   45  *  - multi-threading
   46  *  - sub-pools (pools that can be deleted).
   47  *
   48  * The following sections describe these, beginning with the most basic usage and working up to more
   49  * advanced topics.
   50  *
   51  *
   52  * @section mem_creating Creating a Pool
   53  *
   54  * Before allocating memory from a pool, the pool must be created using le_mem_CreatePool(), passing
   55  * it the name of the pool and the size of the objects to be allocated from that pool. This returns
   56  * a reference to the new pool, which has zero free objects in it.
   57  *
   58  * To populate your new pool with free objects, you call @c le_mem_ExpandPool().
   59  * This is separated into two functions (rather than having
   60  * one function with three parameters) to make it virtually impossible to accidentally get the parameters
   61  * in the wrong order (which would result in nasty bugs that couldn't be caught by the compiler).
   62  * The ability to expand pools comes in handy (see @ref mem_pool_sizes).
   63  *
   64  * This code sample defines a class "Point" and a pool "PointPool" used to
   65  * allocate memory for objects of that class:
   66  * @code
   67  * #define MAX_POINTS 12  // Maximum number of points that can be handled.
   68  *
   69  * typedef struct
   70  * {
   71  *     int x;  // pixel position along x-axis
   72  *     int y;  // pixel position along y-axis
   73  * }
   74  * Point_t;
   75  *
   76  * le_mem_PoolRef_t PointPool;
   77  *
   78  * int xx_pt_ProcessStart(void)
   79  * {
   80  *     PointPool = le_mem_CreatePool("xx.pt.Points", sizeof(Point_t));
   81  *     le_mem_ExpandPool(PointPool, MAX_POINTS);
   82  *
   83  *     return SUCCESS;
   84  * }
   85  * @endcode
   86  *
   87  * To make things easier for power-users, @c le_mem_ExpandPool() returns the same pool
   88  * reference that it was given. This allows the xx_pt_ProcessStart() function to be re-implemented
   89  * as follows:
   90  * @code
   91  * int xx_pt_ProcessStart(void)
   92  * {
   93  *     PointPool = le_mem_ExpandPool(le_mem_CreatePool(sizeof(Point_t)), MAX_POINTS);
   94  *
   95  *     return SUCCESS;
   96  * }
   97  * @endcode
   98  *
   99  * Although this requires a dozen or so fewer keystrokes of typing and occupies one less line
  100  * of code, it's arguably less readable than the previous example.
  101  *
  102  * For a discussion on how to pick the number of objects to have in your pools, see @ref mem_pool_sizes.
  103  *
  104  * @section mem_allocating Allocating From a Pool
  105  *
  106  * Allocating from a pool has multiple options:
  107  *  - @c le_mem_TryAlloc() - Quietly return NULL if there are no free blocks in the pool.
  108  *  - @c le_mem_AssertAlloc() - Log an error and take down the process if there are no free blocks in
  109  *                         the pool.
  110  *  - @c le_mem_ForceAlloc() - If there are no free blocks in the pool, log a warning and automatically
  111  *                         expand the pool (or log an error and terminate the calling process there's
  112  *                         not enough free memory to expand the pool).
  113  *
  114  * All of these functions take a pool reference and return a pointer to the object
  115  * allocated from the pool.
  116  *
  117  * The first option, using @c le_mem_TryAlloc(), is the
  118  *  closest to the way good old malloc() works.  It requires the caller check the
  119  * return code to see if it's NULL.  This can be annoying enough that a lot of
  120  * people get lazy and don't check the return code (Bad programmer! Bad!). It turns out that
  121  * this option isn't really what people usually want (but occasionally they do)
  122  *
  123  * The second option, using @c le_mem_AssertAlloc(), is only used when the allocation should
  124  * never fail, by design; a failure to allocate a block is a fatal error.
  125  * This isn't often used, but can save a lot of boilerplate error checking code.
  126  *
  127  * The third option, @c using le_mem_ForceAlloc(), is the one that gets used most often.
  128  * It allows developers to avoid writing error checking code, because the allocation will
  129  * essentially never fail because it's handled inside the memory allocator.  It also
  130  * allows developers to defer fine tuning their pool sizes until after they get things working.
  131  * Later, they check the logs for pool size usage, and then modify their pool sizes accordingly.
  132  * If a particular pool is continually growing, it's a good indication there's a
  133  * memory leak. This permits seeing exactly what objects are being leaked.  If certain debug
  134  * options are turned on, they can even find out which line in which file allocated the blocks
  135  *  being leaked.
  136  *
  137  *
  138  * @section mem_releasing Releasing Back Into a Pool
  139  *
  140  * Releasing memory back to a pool never fails, so there's no need to check a return code.
  141  * Also, each object knows which pool it came from, so the code that releases the object doesn't have to care.
  142  * All it has to do is call @c le_mem_Release() and pass a pointer to the object to be released.
  143  *
  144  * The critical thing to remember is that once an object has been released, it
  145  * <b> must never be accessed again </b>.  Here is a <b> very bad code example</b>:
  146  * @code
  147  *     Point_t* pointPtr = le_mem_ForceAlloc(PointPool);
  148  *     pointPtr->x = 5;
  149  *     pointPtr->y = 10;
  150  *     le_mem_Release(pointPtr);
  151  *     printf("Point is at position (%d, %d).\n", pointPtr->x, pointPtr->y);
  152  * @endcode
  153  *
  154  *
  155  * @section mem_ref_counting Reference Counting
  156  *
  157  * Reference counting is a powerful feature of our memory pools.  Here's how it works:
  158  *  - Every object allocated from a pool starts with a reference count of 1.
  159  *  - Whenever someone calls le_mem_AddRef() on an object, its reference count is incremented by 1.
  160  *  - When it's released, its reference count is decremented by 1.
  161  *  - When its reference count reaches zero, it's destroyed (i.e., its memory is released back into the pool.)
  162  *
  163  * This allows one function to:
  164  *  - create an object.
  165  *  - work with it.
  166  *  - increment its reference count and pass a pointer to the object to another function (or thread, data structure, etc.).
  167  *  - work with it some more.
  168  *  - release the object without having to worry about when the other function is finished with it.
  169  *
  170  * The other function also releases the object when it's done with it.  So, the object will
  171  * exist until both functions are done.
  172  *
  173  * If there are multiple threads involved, be careful to protect the shared
  174  * object from race conditions(see the @ref mem_threading).
  175  *
  176  * Another great advantage of reference counting is it enables @ref mem_destructors.
  177  *
  178  * @section mem_destructors Destructors
  179  *
  180  * Destructors are a powerful feature of C++.  Anyone who has any non-trivial experience with C++ has
  181  * used them.  Because C was created before object-oriented programming was around, there's
  182  * no native language support for destructors in C.  Object-oriented design is still possible
  183  * and highly desireable even when the programming is done in C.
  184  *
  185  * In Legato, it's possible to call @c le_mem_SetDestructor() to attach a function to a memory pool
  186  * to be used as a destructor for objects allocated from that pool. If a pool has a destructor,
  187  *  whenever the reference count reaches zero for an object allocated from that pool,
  188  * the pool's destructor function will pass a pointer to that object.  After
  189  * the destructor returns, the object will be fully destroyed, and its memory will be released back
  190  * into the pool for later reuse by another object.
  191  *
  192  * Here's a destructor code sample:
  193  * @code
  194  * static void PointDestructor(void* objPtr)
  195  * {
  196  *     Point_t* pointPtr = objPtr;
  197  *
  198  *     printf("Destroying point (%d, %d)\n", pointPtr->x, pointPtr->y);
  199  *
  200  *     @todo Add more to sample.
  201  * }
  202  *
  203  * int xx_pt_ProcessStart(void)
  204  * {
  205  *     PointPool = le_mem_CreatePool(sizeof(Point_t));
  206  *     le_mem_ExpandPool(PointPool, MAX_POINTS);
  207  *     le_mem_SetDestructor(PointPool, PointDestructor);
  208  *     return SUCCESS;
  209  * }
  210  *
  211  * static void DeletePointList(Point_t** pointList, size_t numPoints)
  212  * {
  213  *     size_t i;
  214  *     for (i = 0; i < numPoints; i++)
  215  *     {
  216  *         le_mem_Release(pointList[i]);
  217  *     }
  218  * }
  219  * @endcode
  220  *
  221  * In this sample, when DeletePointList() is called (with a pointer to an array of pointers
  222  * to Point_t objects with reference counts of 1), each of the objects in the pointList is
  223  * released.  This causes their reference counts to hit 0, which triggers executing
  224  * PointDestructor() for each object in the pointList, and the "Destroying point..." message will
  225  * be printed for each.
  226  *
  227  *
  228  * @section mem_stats Statistics
  229  *
  230  * Some statistics are gathered for each memory pool:
  231  *  - Number of allocations.
  232  *  - Number of currently free objects.
  233  *  - Number of overflows (times that le_mem_ForceAlloc() had to expand the pool).
  234  *
  235  * Statistics (and other pool properties) can be checked using functions:
  236  *  - @c le_mem_GetStats()
  237  *  - @c le_mem_GetObjectCount()
  238  *  - @c le_mem_GetObjectSize()
  239  *
  240  * Statistics are fetched together atomically using a single function call.
  241  * This prevents inconsistencies between them if in a multi-threaded program.
  242  *
  243  * If you don't have a reference to a specified pool, but you have the name of the pool, you can
  244  * get a reference to the pool using @c le_mem_FindPool().
  245  *
  246  * In addition to programmatically fetching these, they're also available through the
  247  * "poolstat" console command (unless your process's main thread is blocked).
  248  *
  249  * To reset the pool statistics, use @c le_mem_ResetStats().
  250  *
  251  * @section mem_diagnostics Diagnostics
  252  *
  253  * The memory system also supports two different forms of diagnostics.  Both are enabled by defining
  254  * special preprocessor macros when building the framework.
  255  *
  256  * The first of which is @c LE_MEM_TRACE.  When you define @c LE_MEM_TRACE every pool is given a
  257  * tracepoint with the name of the pool on creation.
  258  *
  259  * For instance, the configTree node pool is called, "configTree.nodePool".  So to enable a trace of
  260  * all config tree node creation and deletion one would use the log tool as follows:
  261  *
  262  * @code
  263  * $ log trace configTree.nodePool
  264  * @endcode
  265  *
  266  * The second diagnostic build flag is @c LE_MEM_VALGRIND.  When @c LE_MEM_VALGRIND is enabled, the
  267  * pools are disabled and instead malloc and free are directly used.  Thus enabling the use of tools
  268  * like Valgrind.
  269  *
  270  * @section mem_threading Multi-Threading
  271  *
  272  * All functions in this API are <b> thread-safe, but not async-safe </b>.  The objects
  273  * allocated from pools are not inherently protected from races between threads.
  274  *
  275  * Allocating and releasing objects, checking stats, incrementing reference
  276  * counts, etc. can all be done from multiple threads (excluding signal handlers) without having
  277  * to worry about corrupting the memory pools' hidden internal data structures.
  278  *
  279  * There's no magical way to prevent different threads from interferring with each other
  280  * if they both access the @a contents of the same object at the same time.
  281  *
  282  * The best way to prevent multi-threaded race conditions is simply don't share data between
  283  * threads. If multiple threads must access the same data structure, then mutexes, semaphores,
  284  * or similar methods should be used to @a synchronize threads and avoid
  285  * data structure corruption or thread misbehaviour.
  286  *
  287  * Although memory pools are @a thread-safe, they are not @a async-safe. This means that memory pools
  288  * @a can be corrupted if they are accessed by a signal handler while they are being accessed
  289  * by a normal thread.  To be safe, <b> don't call any memory pool functions from within a signal handler. </b>
  290  *
  291  * One problem using destructor functions in a
  292  * multi-threaded environment is that the destructor function modifies a data structure shared
  293  * between threads, so it's easy to forget to synchronize calls to @c le_mem_Release() with other code
  294  *  accessing the data structure.  If a mutex is used to coordinate access to
  295  * the data structure, then the mutex must be held by the thread that calls le_mem_Release() to
  296  * ensure there's no other thread accessing the data structure when the destructor runs.
  297  *
  298  * @section mem_pool_sizes Managing Pool Sizes
  299  *
  300  * We know it's possible to have pools automatically expand
  301  * when they are exhausted, but we don't really want that to happen normally.
  302  * Ideally, the pools should be fully allocated to their maximum sizes at start-up so there aren't
  303  * any surprises later when certain feature combinations cause the
  304  * system to run out of memory in the field.  If we allocate everything we think
  305  * is needed up-front, then we are much more likely to uncover any memory shortages during
  306  * testing, before it's in the field.
  307  *
  308  * Choosing the right size for your pools correctly at start-up is easy to do if there is a maximum
  309  * number of fixed, external @a things that are being represented by the objects being allocated
  310  * from the pool.  If the pool holds "call objects" representing phone calls over a T1
  311  * carrier that will never carry more than 24 calls at a time, then it's obvious that you need to
  312  * size your call object pool at 24.
  313  *
  314  * Other times, it's not so easy to choose the pool size like
  315  * code to be reused in different products or different configurations that have different
  316  * needs.  In those cases, you still have a few options:
  317  *
  318  *  - At start-up, query the operating environment and base the pool sizes.
  319  *  - Read a configuration setting from a file or other configuration data source.
  320  *  - Use a build-time configuration setting.
  321  *
  322  * The build-time configuration setting is the easiest, and generally requires less
  323  * interaction between components at start-up simplifying APIs
  324  * and reducing boot times.
  325  *
  326  * If the pool size must be determined at start-up, use @c le_mem_ExpandPool().
  327  * Perhaps there's a service-provider module designed to allocate objects on behalf
  328  * of client. It can have multiple clients at the same time, but it doesn't know how many clients
  329  * or what their resource needs will be until the clients register with it at start-up.  We'd want
  330  * those clients to be as decoupled from each other as possible (i.e., we want the clients know as little
  331  * as possible about each other); we don't want the clients to get together and add up all
  332  * their needs before telling the service-provider.  We'd rather have the clients independently
  333  * report their own needs to the service-provider.  Also, we don't want each client to have to wait
  334  * for all the other clients to report their needs before starting to use
  335  * the services offered by the service-provider.  That would add more complexity to the interactions
  336  * between the clients and the service-provider.
  337  *
  338  * This is what should happen when the service-provider can't wait for all clients
  339  * to report their needs before creating the pool:
  340  *  - When the service-provider starts up, it creates an empty pool.
  341  *  - Whenever a client registers itself with the service-provider, the client can tell the
  342  *    service-provider what its specific needs are, and the service-provider can expand its
  343  *    object pool accordingly.
  344  *  - Since registrations happen at start-up, pool expansion occurs
  345  *    at start-up, and testing will likely find any pool sizing before going into the field.
  346  *
  347  * Where clients dynamically start and stop during runtime in response
  348  * to external events (e.g., when someone is using the device's Web UI), we still have
  349  * a problem because we can't @a shrink pools or delete pools when clients go away.  This is where
  350  * @ref mem_sub_pools is useful.
  351  *
  352  * @section mem_sub_pools Sub-Pools
  353  *
  354  * Essentially, a Sub-Pool is a memory pool that gets its blocks from another pool (the super-pool).
  355  * Sub Pools @a can be deleted, causing its blocks to be released back into the super-pool.
  356  *
  357  * This is useful when a service-provider module needs to handle clients that
  358  * dynamically pop into existence and later disappear again.  When a client attaches to the service
  359  * and says it will probably need a maximum of X of the service-provider's resources, the
  360  * service provider can set aside that many of those resources in a sub-pool for that client.
  361  * If that client goes over its limit, the sub-pool will log a warning message.
  362  *
  363  * The problem of sizing the super-pool correctly at start-up still exists,
  364  * so what's the point of having a sub-pool, when all of the resources could just be allocated from
  365  * the super-pool?
  366  *
  367  * The benefit is really gained in troubleshooting.  If client A, B, C, D and E are
  368  * all behaving nicely, but client F is leaking resources, the sub-pool created
  369  * on behalf of client F will start warning about the memory leak; time won't have to be
  370  * wasted looking at clients A through E to rule them out.
  371  *
  372  * To create a sub-pool, call @c le_mem_CreateSubPool(). It takes a reference to the super-pool
  373  * and the objects specified to the sub-pool, and it returns a reference to the new sub-pool.
  374  *
  375  * To delete a sub-pool, call @c le_mem_DeleteSubPool().  Do not try to use it to delete a pool that
  376  * was created using le_mem_CreatePool().  It's only for sub-pools created using le_mem_CreateSubPool().
  377  * Also, it's @b not okay to delete a sub-pool while there are still blocks allocated from it.
  378  * You'll see errors in your logs if you do that.
  379  *
  380  * Sub-Pools automatically inherit their parent's destructor function.
  381  *
  382  * @note You can't create sub-pools of sub-pools (i.e., sub-pools that get their blocks from another
  383  * sub-pool).
  384  *
  385  * <HR>
  386  *
  387  * Copyright (C) Sierra Wireless Inc. Use of this work is subject to license.
  388  */
  389 
  390 //--------------------------------------------------------------------------------------------------
  391 /** @file le_mem.h
  392  *
  393  * Legato @ref c_memory include file.
  394  *
  395  * Copyright (C) Sierra Wireless Inc. Use of this work is subject to license.
  396  *
  397  */
  398 //--------------------------------------------------------------------------------------------------
  399 
  400 #ifndef LEGATO_MEM_INCLUDE_GUARD
  401 #define LEGATO_MEM_INCLUDE_GUARD
  402 
  403 #ifndef LE_COMPONENT_NAME
  404 #define LE_COMPONENT_NAME
  405 #endif
  406 
  407 
  408 //--------------------------------------------------------------------------------------------------
  409 /**
  410  * Objects of this type are used to refer to a memory pool created using either
  411  * le_mem_CreatePool() or le_mem_CreateSubPool().
  412  */
  413 //--------------------------------------------------------------------------------------------------
  414 typedef struct le_mem_Pool* le_mem_PoolRef_t;
  415 
  416 
  417 //--------------------------------------------------------------------------------------------------
  418 /**
  419  * Prototype for destructor functions.
  420  *
  421  * @param objPtr   Pointer to the object where reference count has reached zero.  After the destructor
  422  *                 returns this object's memory will be released back into the pool (and this pointer
  423  *                 will become invalid).
  424  *
  425  * @return Nothing.
  426  *
  427  * See @ref mem_destructors for more information.
  428  */
  429 //--------------------------------------------------------------------------------------------------
  430 typedef void (*le_mem_Destructor_t)
  431 (
  432     void* objPtr    ///< see parameter documentation in comment above.
  433 );
  434 
  435 
  436 //--------------------------------------------------------------------------------------------------
  437 /**
  438  * List of memory pool statistics.
  439  */
  440 //--------------------------------------------------------------------------------------------------
  441 typedef struct
  442 {
  443     size_t      numBlocksInUse;     ///< Number of currently allocated blocks.
  444     size_t      maxNumBlocksUsed;   ///< Maximum number of allocated blocks at any one time.
  445     size_t      numOverflows;       ///< Number of times le_mem_ForceAlloc() had to expand the pool.
  446     uint64_t    numAllocs;          ///< Number of times an object has been allocated from this pool.
  447     size_t      numFree;            ///< Number of free objects currently available in this pool.
  448 }
  449 le_mem_PoolStats_t;
  450 
  451 
  452 #ifdef LE_MEM_TRACE
  453     //----------------------------------------------------------------------------------------------
  454     /**
  455      * Internal function used to retrieve a pool handle for a given pool block.
  456      */
  457     //----------------------------------------------------------------------------------------------
  458     le_mem_PoolRef_t _le_mem_GetBlockPool
  459     (
  460         void*   objPtr  ///< [IN] Pointer to the object we're finding a pool for.
  461     );
  462 
  463     typedef void* (*_le_mem_AllocFunc_t)(le_mem_PoolRef_t pool);
  464 
  465     //----------------------------------------------------------------------------------------------
  466     /**
  467      * Internal function used to call a memory allocation function and trace its call site.
  468      */
  469     //----------------------------------------------------------------------------------------------
  470     void* _le_mem_AllocTracer
  471     (
  472         le_mem_PoolRef_t     pool,             ///< [IN] The pool activity we're tracing.
  473         _le_mem_AllocFunc_t  funcPtr,          ///< [IN] Pointer to the mem function in question.
  474         const char*          poolFunction,     ///< [IN] The pool function being called.
  475         const char*          file,             ///< [IN] The file the call came from.
  476         const char*          callingfunction,  ///< [IN] The function calling into the pool.
  477         size_t               line              ///< [IN] The line in the function where the call
  478                                                ///       occurred.
  479     );
  480 
  481     //----------------------------------------------------------------------------------------------
  482     /**
  483      * Internal function used to trace memory pool activity.
  484      */
  485     //----------------------------------------------------------------------------------------------
  486     void _le_mem_Trace
  487     (
  488         le_mem_PoolRef_t    pool,             ///< [IN] The pool activity we're tracing.
  489         const char*         file,             ///< [IN] The file the call came from.
  490         const char*         callingfunction,  ///< [IN] The function calling into the pool.
  491         size_t              line,             ///< [IN] The line in the function where the call
  492                                               ///       occurred.
  493         const char*         poolFunction,     ///< [IN] The pool function being called.
  494         void*               blockPtr          ///< [IN] Block allocated/freed.
  495     );
  496 #endif
  497 
  498 
  499 //--------------------------------------------------------------------------------------------------
  500 /** @cond HIDDEN_IN_USER_DOCS
  501  *
  502  * Internal function used to implement le_mem_CreatePool() with automatic component scoping
  503  * of pool names.
  504  */
  505 //--------------------------------------------------------------------------------------------------
  506 le_mem_PoolRef_t _le_mem_CreatePool
  507 (
  508     const char* componentName,  ///< [IN] Name of the component.
  509     const char* name,           ///< [IN] Name of the pool inside the component.
  510     size_t      objSize ///< [IN] Size of the individual objects to be allocated from this pool
  511                         /// (in bytes), e.g., sizeof(MyObject_t).
  512 );
  513 /// @endcond
  514 
  515 
  516 //--------------------------------------------------------------------------------------------------
  517 /**
  518  * Creates an empty memory pool.
  519  *
  520  * @return
  521  *      Reference to the memory pool object.
  522  *
  523  * @note
  524  *      On failure, the process exits, so you don't have to worry about checking the returned
  525  *      reference for validity.
  526  */
  527 //--------------------------------------------------------------------------------------------------
  528 static inline le_mem_PoolRef_t le_mem_CreatePool
  529 (
  530     const char* name,   ///< [IN] Name of the pool (will be copied into the Pool).
  531     size_t      objSize ///< [IN] Size of the individual objects to be allocated from this pool
  532                         /// (in bytes), e.g., sizeof(MyObject_t).
  533 )
  534 {
  535     return _le_mem_CreatePool(STRINGIZE(LE_COMPONENT_NAME), name, objSize);
  536 }
  537 
  538 
  539 //--------------------------------------------------------------------------------------------------
  540 /**
  541  * Expands the size of a memory pool.
  542  *
  543  * @return  Reference to the memory pool object (the same value passed into it).
  544  *
  545  * @note    On failure, the process exits, so you don't have to worry about checking the returned
  546  *          reference for validity.
  547  */
  548 //--------------------------------------------------------------------------------------------------
  549 le_mem_PoolRef_t le_mem_ExpandPool
  550 (
  551     le_mem_PoolRef_t    pool,       ///< [IN] Pool to be expanded.
  552     size_t              numObjects  ///< [IN] Number of objects to add to the pool.
  553 );
  554 
  555 
  556 
  557 #ifndef LE_MEM_TRACE
  558     //----------------------------------------------------------------------------------------------
  559     /**
  560      * Attempts to allocate an object from a pool.
  561      *
  562      * @return
  563      *      Pointer to the allocated object, or NULL if the pool doesn't have any free objects
  564      *      to allocate.
  565      */
  566     //----------------------------------------------------------------------------------------------
  567     void* le_mem_TryAlloc
  568     (
  569         le_mem_PoolRef_t    pool    ///< [IN] Pool from which the object is to be allocated.
  570     );
  571 #else
  572     /// @cond HIDDEN_IN_USER_DOCS
  573     void* _le_mem_TryAlloc(le_mem_PoolRef_t pool);
  574     /// @endcond
  575 
  576     #define le_mem_TryAlloc(pool)                                                                   \
  577         _le_mem_AllocTracer(pool,                                                                   \
  578                             _le_mem_TryAlloc,                                                       \
  579                             "le_mem_TryAlloc",                                                      \
  580                             STRINGIZE(LE_FILENAME),                                                 \
  581                             __FUNCTION__,                                                           \
  582                             __LINE__)
  583 
  584 #endif
  585 
  586 
  587 #ifndef LE_MEM_TRACE
  588     //----------------------------------------------------------------------------------------------
  589     /**
  590      * Allocates an object from a pool or logs a fatal error and terminates the process if the pool
  591      * doesn't have any free objects to allocate.
  592      *
  593      * @return Pointer to the allocated object.
  594      *
  595      * @note    On failure, the process exits, so you don't have to worry about checking the
  596      *          returned pointer for validity.
  597      */
  598     //----------------------------------------------------------------------------------------------
  599     void* le_mem_AssertAlloc
  600     (
  601         le_mem_PoolRef_t    pool    ///< [IN] Pool from which the object is to be allocated.
  602     );
  603 #else
  604     /// @cond HIDDEN_IN_USER_DOCS
  605     void* _le_mem_AssertAlloc(le_mem_PoolRef_t pool);
  606     /// @endcond
  607 
  608     #define le_mem_AssertAlloc(pool)                                                                \
  609         _le_mem_AllocTracer(pool,                                                                   \
  610                             _le_mem_AssertAlloc,                                                    \
  611                             "le_mem_AssertAlloc",                                                   \
  612                             STRINGIZE(LE_FILENAME),                                                 \
  613                             __FUNCTION__,                                                           \
  614                             __LINE__)
  615 #endif
  616 
  617 
  618 #ifndef LE_MEM_TRACE
  619     //----------------------------------------------------------------------------------------------
  620     /**
  621      * Allocates an object from a pool or logs a warning and expands the pool if the pool
  622      * doesn't have any free objects to allocate.
  623      *
  624      * @return  Pointer to the allocated object.
  625      *
  626      * @note    On failure, the process exits, so you don't have to worry about checking the
  627      *          returned pointer for validity.
  628      */
  629     //----------------------------------------------------------------------------------------------
  630     void* le_mem_ForceAlloc
  631     (
  632         le_mem_PoolRef_t    pool    ///< [IN] Pool from which the object is to be allocated.
  633     );
  634 #else
  635     /// @cond HIDDEN_IN_USER_DOCS
  636     void* _le_mem_ForceAlloc(le_mem_PoolRef_t pool);
  637     /// @endcond
  638 
  639     #define le_mem_ForceAlloc(pool)                                                                 \
  640         _le_mem_AllocTracer(pool,                                                                   \
  641                             _le_mem_ForceAlloc,                                                     \
  642                             "le_mem_ForceAlloc",                                                    \
  643                             STRINGIZE(LE_FILENAME),                                                 \
  644                             __FUNCTION__,                                                           \
  645                             __LINE__)
  646 #endif
  647 
  648 
  649 //--------------------------------------------------------------------------------------------------
  650 /**
  651  * Sets the number of objects that are added when le_mem_ForceAlloc expands the pool.
  652  *
  653  * @return
  654  *      Nothing.
  655  *
  656  * @note
  657  *      The default value is one.
  658  */
  659 //--------------------------------------------------------------------------------------------------
  660 void le_mem_SetNumObjsToForce
  661 (
  662     le_mem_PoolRef_t    pool,       ///< [IN] Pool to set the number of objects for.
  663     size_t              numObjects  ///< [IN] Number of objects that is added when
  664                                     ///       le_mem_ForceAlloc expands the pool.
  665 );
  666 
  667 
  668 #ifndef LE_MEM_TRACE
  669     //----------------------------------------------------------------------------------------------
  670     /**
  671      * Releases an object.  If the object's reference count has reached zero, it will be destructed
  672      * and its memory will be put back into the pool for later reuse.
  673      *
  674      * @return
  675      *      Nothing.
  676      *
  677      * @warning
  678      *      - <b>Don't EVER access an object after releasing it.</b>  It might not exist anymore.
  679      *      - If the object has a destructor accessing a data structure shared by multiple
  680      *        threads, ensure you hold the mutex (or take other measures to prevent races) before
  681      *        releasing the object.
  682      */
  683     //----------------------------------------------------------------------------------------------
  684     void le_mem_Release
  685     (
  686         void*   objPtr  ///< [IN] Pointer to the object to be released.
  687     );
  688 #else
  689     /// @cond HIDDEN_IN_USER_DOCS
  690     void _le_mem_Release(void* objPtr);
  691     /// @endcond
  692 
  693     #define le_mem_Release(objPtr)                                                                  \
  694             _le_mem_Trace(_le_mem_GetBlockPool(objPtr),                                             \
  695                           STRINGIZE(LE_FILENAME),                                                   \
  696                           __FUNCTION__,                                                             \
  697                           __LINE__,                                                                 \
  698                           "le_mem_Release",                                                         \
  699                           (objPtr));                                                                \
  700             _le_mem_Release(objPtr);
  701 #endif
  702 
  703 
  704 #ifndef LE_MEM_TRACE
  705     //----------------------------------------------------------------------------------------------
  706     /**
  707      * Increments the reference count on an object by 1.
  708      *
  709      * See @ref mem_ref_counting for more information.
  710      *
  711      * @return
  712      *      Nothing.
  713      */
  714     //----------------------------------------------------------------------------------------------
  715     void le_mem_AddRef
  716     (
  717         void*   objPtr  ///< [IN] Pointer to the object.
  718     );
  719 #else
  720     /// @cond HIDDEN_IN_USER_DOCS
  721     void _le_mem_AddRef(void* objPtr);
  722     /// @endcond
  723 
  724     #define le_mem_AddRef(objPtr)                                                                   \
  725         _le_mem_Trace(_le_mem_GetBlockPool(objPtr),                                                 \
  726                       STRINGIZE(LE_FILENAME),                                                       \
  727                       __FUNCTION__,                                                                 \
  728                       __LINE__,                                                                     \
  729                       "le_mem_AddRef",                                                              \
  730                       (objPtr));                                                                    \
  731         _le_mem_AddRef(objPtr);
  732 #endif
  733 
  734 
  735 //--------------------------------------------------------------------------------------------------
  736 /**
  737  * Sets the destructor function for a specified pool.
  738  *
  739  * See @ref mem_destructors for more information.
  740  *
  741  * @return
  742  *      Nothing.
  743  */
  744 //--------------------------------------------------------------------------------------------------
  745 void le_mem_SetDestructor
  746 (
  747     le_mem_PoolRef_t    pool,       ///< [IN] The pool.
  748     le_mem_Destructor_t destructor  ///< [IN] Destructor function.
  749 );
  750 
  751 
  752 //--------------------------------------------------------------------------------------------------
  753 /**
  754  * Fetches the statistics for a specified pool.
  755  *
  756  * @return
  757  *      Nothing.  Uses output parameter instead.
  758  */
  759 //--------------------------------------------------------------------------------------------------
  760 void le_mem_GetStats
  761 (
  762     le_mem_PoolRef_t    pool,       ///< [IN] Pool where stats are to be fetched.
  763     le_mem_PoolStats_t* statsPtr    ///< [OUT] Pointer to where the stats will be stored.
  764 );
  765 
  766 
  767 //--------------------------------------------------------------------------------------------------
  768 /**
  769  * Resets the statistics for a specified pool.
  770  *
  771  * @return
  772  *      Nothing.
  773  */
  774 //--------------------------------------------------------------------------------------------------
  775 void le_mem_ResetStats
  776 (
  777     le_mem_PoolRef_t    pool        ///< [IN] Pool where stats are to be reset.
  778 );
  779 
  780 
  781 //--------------------------------------------------------------------------------------------------
  782 /**
  783  * Gets the memory pool's name, including the component name prefix.
  784  *
  785  * If the pool were given the name "myPool" and the component that it belongs to is called
  786  * "myComponent", then the full pool name returned by this function would be "myComponent.myPool".
  787  *
  788  * @return
  789  *      LE_OK if successful.
  790  *      LE_OVERFLOW if the name was truncated to fit in the provided buffer.
  791  */
  792 //--------------------------------------------------------------------------------------------------
  793 le_result_t le_mem_GetName
  794 (
  795     le_mem_PoolRef_t    pool,       ///< [IN] The memory pool.
  796     char*               namePtr,    ///< [OUT] Buffer to store the name of the memory pool.
  797     size_t              bufSize     ///< [IN] Size of the buffer namePtr points to.
  798 );
  799 
  800 
  801 //--------------------------------------------------------------------------------------------------
  802 /**
  803  * Checks if the specified pool is a sub-pool.
  804  *
  805  * @return
  806  *      true if it is a sub-pool.
  807  *      false if it is not a sub-pool.
  808  */
  809 //--------------------------------------------------------------------------------------------------
  810 const bool le_mem_IsSubPool
  811 (
  812     le_mem_PoolRef_t    pool        ///< [IN] The memory pool.
  813 );
  814 
  815 
  816 //--------------------------------------------------------------------------------------------------
  817 /**
  818  * Fetches the number of objects a specified pool can hold (this includes both the number of
  819  * free and in-use objects).
  820  *
  821  * @return
  822  *      Total number of objects.
  823  */
  824 //--------------------------------------------------------------------------------------------------
  825 size_t le_mem_GetObjectCount
  826 (
  827     le_mem_PoolRef_t    pool        ///< [IN] Pool where number of objects is to be fetched.
  828 );
  829 
  830 
  831 //--------------------------------------------------------------------------------------------------
  832 /**
  833  * Fetches the size of the objects in a specified pool (in bytes).
  834  *
  835  * @return
  836  *      Object size, in bytes.
  837  */
  838 //--------------------------------------------------------------------------------------------------
  839 size_t le_mem_GetObjectSize
  840 (
  841     le_mem_PoolRef_t    pool        ///< [IN] Pool where object size is to be fetched.
  842 );
  843 
  844 
  845 //--------------------------------------------------------------------------------------------------
  846 /**
  847  * Fetches the total size of the object including all the memory overhead in a given pool (in bytes).
  848  *
  849  * @return
  850  *      Total object memory size, in bytes.
  851  */
  852 //--------------------------------------------------------------------------------------------------
  853 size_t le_mem_GetObjectFullSize
  854 (
  855     le_mem_PoolRef_t    pool        ///< [IN] The pool whose object memory size is to be fetched.
  856 );
  857 
  858 
  859 //--------------------------------------------------------------------------------------------------
  860 /** @cond HIDDEN_IN_USER_DOCS
  861  *
  862  * Internal function used to implement le_mem_FindPool() with automatic component scoping
  863  * of pool names.
  864  */
  865 //--------------------------------------------------------------------------------------------------
  866 le_mem_PoolRef_t _le_mem_FindPool
  867 (
  868     const char* componentName,  ///< [IN] Name of the component.
  869     const char* name            ///< [IN] Name of the pool inside the component.
  870 );
  871 /// @endcond
  872 
  873 
  874 //--------------------------------------------------------------------------------------------------
  875 /**
  876  * Finds a pool based on the pool's name.
  877  *
  878  * @return
  879  *      Reference to the pool, or NULL if the pool doesn't exist.
  880  */
  881 //--------------------------------------------------------------------------------------------------
  882 static inline le_mem_PoolRef_t le_mem_FindPool
  883 (
  884     const char* name    ///< [IN] Name of the pool.
  885 )
  886 {
  887     return _le_mem_FindPool(STRINGIZE(LE_COMPONENT_NAME), name);
  888 }
  889 
  890 
  891 //--------------------------------------------------------------------------------------------------
  892 /** @cond HIDDEN_IN_USER_DOCS
  893  *
  894  * Internal function used to implement le_mem_CreateSubPool() with automatic component scoping
  895  * of pool names.
  896  */
  897 //--------------------------------------------------------------------------------------------------
  898 le_mem_PoolRef_t _le_mem_CreateSubPool
  899 (
  900     le_mem_PoolRef_t    superPool,  ///< [IN] Super-pool.
  901     const char*     componentName,  ///< [IN] Name of the component.
  902     const char*         name,       ///< [IN] Name of the sub-pool (will be copied into the
  903                                     ///   sub-pool).
  904     size_t              numObjects  ///< [IN] Number of objects to take from the super-pool.
  905 );
  906 /// @endcond
  907 
  908 
  909 //--------------------------------------------------------------------------------------------------
  910 /**
  911  * Creates a sub-pool.  You can't create sub-pools of sub-pools so do not attempt to pass a
  912  * sub-pool in the superPool parameter.
  913  *
  914  * See @ref mem_sub_pools for more information.
  915  *
  916  * @return
  917  *      Reference to the sub-pool.
  918  */
  919 //--------------------------------------------------------------------------------------------------
  920 static inline le_mem_PoolRef_t le_mem_CreateSubPool
  921 (
  922     le_mem_PoolRef_t    superPool,  ///< [IN] Super-pool.
  923     const char*         name,       ///< [IN] Name of the sub-pool (will be copied into the
  924                                     ///   sub-pool).
  925     size_t              numObjects  ///< [IN] Number of objects to take from the super-pool.
  926 )
  927 {
  928     return _le_mem_CreateSubPool(superPool, STRINGIZE(LE_COMPONENT_NAME), name, numObjects);
  929 }
  930 
  931 
  932 //--------------------------------------------------------------------------------------------------
  933 /**
  934  * Deletes a sub-pool.
  935  *
  936  * See @ref mem_sub_pools for more information.
  937  *
  938  * @return
  939  *      Nothing.
  940  */
  941 //--------------------------------------------------------------------------------------------------
  942 void le_mem_DeleteSubPool
  943 (
  944     le_mem_PoolRef_t    subPool     ///< [IN] Sub-pool to be deleted.
  945 );
  946 
  947 
  948 #endif // LEGATO_MEM_INCLUDE_GUARD
le_mem_TryAlloc
void * le_mem_TryAlloc(le_mem_PoolRef_t pool)
le_mem_ExpandPool
le_mem_PoolRef_t le_mem_ExpandPool(le_mem_PoolRef_t pool, size_t numObjects)
le_mem_PoolStats_t::numAllocs
uint64_t numAllocs
Number of times an object has been allocated from this pool. 
Definition: le_mem.h:446
le_result_t
le_result_t
Definition: le_basics.h:35
le_mem_AssertAlloc
void * le_mem_AssertAlloc(le_mem_PoolRef_t pool)
le_mem_GetStats
void le_mem_GetStats(le_mem_PoolRef_t pool, le_mem_PoolStats_t *statsPtr)
le_mem_IsSubPool
const bool le_mem_IsSubPool(le_mem_PoolRef_t pool)
le_mem_PoolStats_t::numBlocksInUse
size_t numBlocksInUse
Number of currently allocated blocks. 
Definition: le_mem.h:443
le_mem_FindPool
static le_mem_PoolRef_t le_mem_FindPool(const char *name)
Definition: le_mem.h:883
le_mem_PoolStats_t::maxNumBlocksUsed
size_t maxNumBlocksUsed
Maximum number of allocated blocks at any one time. 
Definition: le_mem.h:444
STRINGIZE
#define STRINGIZE(x)
Definition: le_basics.h:206
le_mem_SetDestructor
void le_mem_SetDestructor(le_mem_PoolRef_t pool, le_mem_Destructor_t destructor)
le_mem_CreatePool
static le_mem_PoolRef_t le_mem_CreatePool(const char *name, size_t objSize)
Definition: le_mem.h:529
le_mem_ResetStats
void le_mem_ResetStats(le_mem_PoolRef_t pool)
le_mem_SetNumObjsToForce
void le_mem_SetNumObjsToForce(le_mem_PoolRef_t pool, size_t numObjects)
le_mem_DeleteSubPool
void le_mem_DeleteSubPool(le_mem_PoolRef_t subPool)
le_mem_PoolRef_t
struct le_mem_Pool * le_mem_PoolRef_t
Definition: le_mem.h:414
le_mem_GetName
le_result_t le_mem_GetName(le_mem_PoolRef_t pool, char *namePtr, size_t bufSize)
le_mem_Release
void le_mem_Release(void *objPtr)
le_mem_PoolStats_t::numFree
size_t numFree
Number of free objects currently available in this pool. 
Definition: le_mem.h:447
le_mem_PoolStats_t::numOverflows
size_t numOverflows
Number of times le_mem_ForceAlloc() had to expand the pool. 
Definition: le_mem.h:445
le_mem_Destructor_t
void(* le_mem_Destructor_t)(void *objPtr)
Definition: le_mem.h:431
le_mem_GetObjectCount
size_t le_mem_GetObjectCount(le_mem_PoolRef_t pool)
le_mem_PoolStats_t
Definition: le_mem.h:441
le_mem_GetObjectFullSize
size_t le_mem_GetObjectFullSize(le_mem_PoolRef_t pool)
le_mem_GetObjectSize
size_t le_mem_GetObjectSize(le_mem_PoolRef_t pool)
le_mem_AddRef
void le_mem_AddRef(void *objPtr)
le_mem_ForceAlloc
void * le_mem_ForceAlloc(le_mem_PoolRef_t pool)
le_mem_CreateSubPool
static le_mem_PoolRef_t le_mem_CreateSubPool(le_mem_PoolRef_t superPool, const char *name, size_t numObjects)
Definition: le_mem.h:921