mm/cma_debug.c

Source file repositories/reference/linux-study-clean/mm/cma_debug.c

File Facts

System
Linux kernel
Corpus path
mm/cma_debug.c
Extension
.c
Size
4988 bytes
Lines
214
Domain
Core OS
Bucket
Memory Management
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct cma_mem {
	struct hlist_node node;
	struct page *p;
	unsigned long n;
};

static int cma_debugfs_get(void *data, u64 *val)
{
	unsigned long *p = data;

	*val = *p;

	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");

static int cma_used_get(void *data, u64 *val)
{
	struct cma *cma = data;

	spin_lock_irq(&cma->lock);
	*val = cma->count - cma->available_count;
	spin_unlock_irq(&cma->lock);

	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");

static int cma_maxchunk_get(void *data, u64 *val)
{
	struct cma *cma = data;
	struct cma_memrange *cmr;
	unsigned long maxchunk = 0;
	unsigned long start, end;
	unsigned long bitmap_maxno;
	int r;

	spin_lock_irq(&cma->lock);
	for (r = 0; r < cma->nranges; r++) {
		cmr = &cma->ranges[r];
		bitmap_maxno = cma_bitmap_maxno(cma, cmr);
		for_each_clear_bitrange(start, end, cmr->bitmap, bitmap_maxno)
			maxchunk = max(end - start, maxchunk);
	}
	spin_unlock_irq(&cma->lock);
	*val = (u64)maxchunk << cma->order_per_bit;

	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");

static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
{
	spin_lock(&cma->mem_head_lock);
	hlist_add_head(&mem->node, &cma->mem_head);
	spin_unlock(&cma->mem_head_lock);
}

static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
{
	struct cma_mem *mem = NULL;

	spin_lock(&cma->mem_head_lock);
	if (!hlist_empty(&cma->mem_head)) {
		mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
		hlist_del_init(&mem->node);
	}
	spin_unlock(&cma->mem_head_lock);

	return mem;
}

static int cma_free_mem(struct cma *cma, int count)
{
	struct cma_mem *mem = NULL;

	while (count) {
		mem = cma_get_entry_from_list(cma);
		if (mem == NULL)
			return 0;

		if (mem->n <= count) {
			cma_release(cma, mem->p, mem->n);
			count -= mem->n;
			kfree(mem);
		} else if (cma->order_per_bit == 0) {
			cma_release(cma, mem->p, count);
			mem->p += count;
			mem->n -= count;
			count = 0;

Annotation

Implementation Notes