LittleKernel学习笔记（5）

heap_init

static inline void HEAP_INIT(void) {
/* start the heap off with some spare memory in the page allocator */
size_t len;
void *ptr = page_first_alloc(&len);
miniheap_init(ptr, len);
}

 

 1 void miniheap_init(void *ptr, size_t len) {
 2     LTRACEF("ptr %p, len %zu\n", ptr, len);
 3 
 4     // create a mutex
 5     mutex_init(&theheap.lock);
 6 
 7     // initialize the free list
 8     list_initialize(&theheap.free_list);
 9 
10     // align the buffer to a ptr
11     if (((uintptr_t)ptr % sizeof(uintptr_t)) > 0) {
12         uintptr_t aligned_ptr = ROUNDUP((uintptr_t)ptr, sizeof(uintptr_t));
13 
14         DEBUG_ASSERT((aligned_ptr - (uintptr_t)ptr) < len);
15 
16         len -= aligned_ptr - (uintptr_t)ptr;
17         ptr = (void *)aligned_ptr;
18 
19         LTRACEF("(aligned) ptr %p, len %zu\n", ptr, len);
20     }
21 
22     // set the heap range
23     theheap.base = ptr;
24     theheap.len = len;
25     theheap.remaining = 0; // will get set by heap_insert_free_chunk()
26     theheap.low_watermark = 0;
27 
28     // if passed a default range, use it
29     if (len > 0)
30         heap_insert_free_chunk(heap_create_free_chunk(ptr, len, true));
31 }

 

posted @ 2021-08-31 18:13  zhougong12  阅读(125)  评论(0)    收藏  举报