[ThreadX, 5] memory

2017年10月31日

下午 03:22

Byte pool:

• 範例:

/* Create a memory pool whose total size is 2000 bytes

starting at address 0x500000. */

status = tx_byte_pool_create(&my_pool, "my_pool", (VOID *) 0x500000, 2000);

/* Allocate a 112 byte memory area from my_pool. Assume

that the byte pool has already been created with a call to tx_byte_pool_create. */

status = tx_byte_allocate(&my_pool, (VOID **) &memory_ptr, 112, TX_WAIT_FOREVER);

Block pool:

• 範例(create 時除了定義pool大小外還需要定義每一個block的大小，allocate時則不用):

/* Create a memory pool whose total size is 1000 bytes starting at address 0x100000. Each block in this

pool is defined to be 50 bytes long. */

status = tx_block_pool_create(&my_pool, "my_pool_name", 50, (VOID *) 0x100000, 1000);

status = tx_block_allocate(&my_pool, (VOID **) &memory_ptr, TX_WAIT_FOREVER);

• byte/block pool 都是利用 link list做管理，當有記憶體問題時可以dump出此list來做檢查(如CB是否被破壞)。

• 比較兩者，Byte較為靈活但有碎片以及效率(搜尋可用大小，整理碎片)的問題；嵌入式系統中建議使用block pool，透過create不同的block pool來增加靈活度，減輕其不足的部分。