Merge pull request #7651 from tobhe/memarray

Generic memory block allocator

sys/include/memarray.h

+/*
+ * Copyright (C) 2018 Tobias Heider <heidert@nm.ifi.lmu.de>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+/**
+ * @defgroup    sys_memarray memory array allocator
+ * @ingroup     sys
+ * @brief       memory array allocator
+ * @{
+ *
+ * @brief       pseudo dynamic allocation in static memory arrays
+ * @author      Tobias Heider <heidert@nm.ifi.lmu.de>
+ */
+
+#ifndef MEMARRAY_H
+#define MEMARRAY_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Memory pool
+ */
+typedef struct {
+    void *free_data;    /**< memory pool data / head of the free list */
+    size_t size;        /**< size of single list element */
+    size_t num;         /**< max number of elements in list */
+} memarray_t;
+
+/**
+ * @brief Initialize memarray pool with free list
+ *
+ * @pre `mem != NULL`
+ * @pre `data != NULL`
+ * @pre `size >= sizeof(void*)`
+ * @pre `num != 0`
+ *
+ * @param[in,out] mem    memarray pool to initialize
+ * @param[in]     data   pointer to user-allocated data
+ * @param[in]     size   size of a single element in data
+ * @param[in]     num    number of elements in data
+ */
+void memarray_init(memarray_t *mem, void *data, size_t size, size_t num);
+
+/**
+ * @brief Allocate memory chunk in memarray pool
+ *
+ * @pre `mem != NULL`
+ *
+ * @param[in,out] mem   memarray pool to allocate block in
+ *
+ * @return pointer to allocated structure, if enough memory was available
+ * @return NULL, on failure
+ */
+void *memarray_alloc(memarray_t *mem);
+
+/**
+ * @brief Free memory chunk in memarray pool
+ *
+ * @pre `mem != NULL`
+ * @pre `ptr != NULL`
+ *
+ * @param[in,out] mem   memarray pool to free block in
+ * @param[in]     ptr   pointer to memarray chunk
+ */
+void memarray_free(memarray_t *mem, void *ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MEMARRAY_H */
+
+/**
+ * @}
+ */

sys/memarray/Makefile

+include $(RIOTBASE)/Makefile.base

sys/memarray/memarray.c

+/*
+ * Copyright (C) 2018 Tobias Heider <heidert@nm.ifi.lmu.de>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+#include <string.h>
+#include "memarray.h"
+
+#define ENABLE_DEBUG    (0)
+#include "debug.h"
+
+void memarray_init(memarray_t *mem, void *data, size_t size, size_t num)
+{
+    assert((mem != NULL) && (data != NULL) && (size >= sizeof(void *)) &&
+           (num != 0));
+
+    DEBUG("memarray: Initialize memarray of %u times %u Bytes at %p\n",
+          (unsigned)num, (unsigned)size, data);
+
+    mem->free_data = data;
+    mem->size = size;
+    mem->num = num;
+
+    for (size_t i = 0; i < (mem->num - 1); i++) {
+        void *next = ((char *)mem->free_data) + ((i + 1) * mem->size);
+        memcpy(((char *)mem->free_data) + (i * mem->size), &next, sizeof(void *));
+    }
+}
+
+void *memarray_alloc(memarray_t *mem)
+{
+    assert(mem != NULL);
+
+    if (mem->free_data == NULL) {
+        return NULL;
+    }
+    void *free = mem->free_data;
+    mem->free_data = *((void **)mem->free_data);
+    DEBUG("memarray: Allocate %u Bytes at %p\n", (unsigned)mem->size, free);
+    return free;
+}
+
+void memarray_free(memarray_t *mem, void *ptr)
+{
+    assert((mem != NULL) && (ptr != NULL));
+
+    memcpy(ptr, &mem->free_data, sizeof(void *));
+    mem->free_data = ptr;
+    DEBUG("memarray: Free %u Bytes at %p\n", (unsigned)mem->size, ptr);
+}

tests/memarray/Makefile

+include ../Makefile.tests_common
+USEMODULE += memarray
+
+# Used for invoking _ps_handler
+USEMODULE += shell_commands
+USEMODULE += ps
+
+include $(RIOTBASE)/Makefile.include

tests/memarray/README.md

+Expected result
+===============
+
+This application should run a number of tests equal to NUMBER_OF_TESTS (Default 12).
+
+At the beginning of the tests memory usage of each thread is printed.
+At the end of the tests, the threads memory usage is printed once more time.
+
+This test is passed if the memory used by the main thread remains static.
+
+Background
+==========
+
+The module `memarray` is the fixed-size block allocator for RIOT-OS.
+
+This test application is therefore specialized for only testing the use of the module.
+
+This is also inspired by `test/malloc`.

tests/memarray/main.c

+/*
+ * Copyright (C) 2018 Inria
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       Simple memarray module tests
+ *
+ * @author      Tobias Heider <heidert@nm.ifi.lmu.de>
+ * @author      Raul Fuentes <raul.fuentes-samaniego@inria.fr>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "memarray.h"
+
+#define MAX_NUMBER_BLOCKS    (10)
+#define MESSAGE_SIZE         (8U)
+#define NUMBER_OF_TESTS      (12)
+
+extern int _ps_handler(int argc, char **argv);
+
+struct block_t {
+    struct node *next;
+    int number;
+    /* static size for the components */
+    unsigned char message[MESSAGE_SIZE];
+};
+
+struct block_t block_storage_data[MAX_NUMBER_BLOCKS];
+memarray_t block_storage;
+
+int total = 0;
+
+static void memory_block_init(void)
+{
+    memarray_init(&block_storage, block_storage_data, sizeof(struct block_t), MAX_NUMBER_BLOCKS);
+}
+
+void fill_memory(struct block_t *head)
+{
+    int aux = 0;
+
+    while ((aux < MAX_NUMBER_BLOCKS) && (head)) {
+        memset(head->message, '@', MESSAGE_SIZE - 1);
+        head->message[MESSAGE_SIZE - 1] = 0;
+        head->number = aux;
+
+        printf("\t(%i, %s) Allocated %u Bytes at %p, total %d\n",
+               head->number, head->message, (unsigned)sizeof(struct block_t),
+               (void *)head, total);
+
+        /* NOTE: If there is not space, memarray_alloc returns zero */
+        head->next = memarray_alloc(&block_storage);
+        head = (struct block_t *)head->next;
+
+        total += sizeof(struct block_t);
+        aux++;
+    }
+}
+
+void free_memory(struct block_t *head)
+{
+    struct block_t *old;
+
+    while (head) {
+        total -= sizeof(struct block_t);
+        printf("\tFree (%i) %u Bytes at %p, total %d\n", \
+               head->number, (unsigned)sizeof(struct block_t),
+               (void *)head, total);
+
+        if (head->next) {
+            old = head;
+            head = (struct block_t *) head->next;
+            memarray_free(&block_storage, old);
+        }
+        else {
+            memarray_free(&block_storage, head);
+            head = 0;
+        }
+    }
+}
+
+int main(void)
+{
+    memory_block_init();
+    int count = 0;
+
+    printf("Starting (%d, %u)\n", MAX_NUMBER_BLOCKS, MESSAGE_SIZE);
+    _ps_handler(0, NULL);
+
+    while (count < NUMBER_OF_TESTS) {
+        struct block_t *head = (struct block_t *) memarray_alloc(&block_storage);
+
+        printf("TEST #%i:\n", count + 1 );
+        fill_memory(head);
+        free_memory(head);
+
+        count++;
+    }
+
+    printf("Finishing\n");
+    _ps_handler(0, NULL);
+
+    return 0;
+}