struct page *alloc_pages(struct buddy *node, unsigned int order)
{
struct page *page;
struct buddy_freelist *freelist;
struct links *head, *curr;
unsigned int i, n;
freelist = &node->freelist[order];
page = NULL;
unsigned int irqflag;
spin_lock_irqsave(&node->lock, irqflag);
for (i = order; i < BUDDY_MAX_ORDER; i++, freelist++) {
head = &freelist->list;
curr = head->next;
if (curr == head)
continue;
page = get_container_of(curr, struct page, list);
RESET_PAGE_FLAG(page, PAGE_BUDDY);
links_del(curr);
freelist->nr_pageblocks--;
/* split in half to add one of them to the current order list
* if allocating from a higher order */
while (i > order) {
freelist--;
i--;
n = 1U << i;
SET_PAGE_FLAG(&page[n], PAGE_BUDDY);
SET_PAGE_ORDER(&page[n], i);
links_add(&page[n].list, &freelist->list);
freelist->nr_pageblocks++;
}
node->nr_free -= 1 << order;
RESET_PAGE_FLAG(page, PAGE_BUDDY);
SET_PAGE_ORDER(page, i);
break;
}
spin_unlock_irqrestore(&node->lock, irqflag);
return page;
}
static void buddy_freelist_init(struct buddy *node, size_t nr_pages,
struct page *mem_map)
{
extern unsigned int _ram_start;
unsigned int order, idx, preserved, nr_free, n;
/* Preserve the initial kernel stack to be free later, which is located
* at the end of memory */
preserved = nr_pages - PAGE_NR(ALIGN_PAGE(STACK_SIZE));
order = mylog2(PAGE_NR(ALIGN_PAGE(STACK_SIZE)));
SET_PAGE_ORDER(&mem_map[preserved], order);
/* And mark kernel .data and .bss sections as used.
* The region of mem_map array as well. */
idx = PAGE_NR(ALIGN_PAGE(&mem_map[nr_pages]) -
(unsigned int)&_ram_start);
nr_free = preserved - idx;
debug(MSG_DEBUG, "The first free page(idx:%d) - %x",
idx, &mem_map[nr_pages]);
debug(MSG_DEBUG, "The number of free pages %d", nr_free);
struct page *page;
while (nr_free) {
order = min(mylog2(idx), BUDDY_MAX_ORDER - 1);
while ((int)(nr_free - (1U << order)) < 0)
order--;
page = &mem_map[idx];
SET_PAGE_ORDER(page, order);
SET_PAGE_FLAG(page, PAGE_BUDDY);
links_add(&page->list, &node->freelist[order].list);
node->freelist[order].nr_pageblocks++;
debug(MSG_DEBUG, "%02d %x added to %x", order, &page->list,
&node->freelist[order].list);
n = 1U << order;
debug(MSG_DEBUG, "%04d: idx %d buddy %d head %d",
n, idx, idx ^ n, idx & ~n);
idx += n;
nr_free -= n;
node->nr_free += n; /* total pages being managed by buddy */
debug(MSG_DEBUG, "order %d, nr_free %d, next %d\n",
order, nr_free, idx);
}
}
void free_pages(struct buddy *node, struct page *page)
{
struct page *buddy, *mem_map;
struct buddy_freelist *freelist;
unsigned int order, idx, n;
unsigned int irqflag;
mem_map = node->mem_map;
idx = page - mem_map;
order = GET_PAGE_ORDER(page);
freelist = &node->freelist[order];
n = 1U << order;
spin_lock_irqsave(&node->lock, irqflag);
node->nr_free += n;
while (order < (BUDDY_MAX_ORDER - 1)) {
n = 1U << order;
buddy = &mem_map[idx ^ n];
if (!is_buddy_free(page, buddy, order))
break;
links_del(&buddy->list);
freelist->nr_pageblocks--;
RESET_PAGE_FLAG(buddy, PAGE_BUDDY);
idx &= ~n; /* grab the head of merging buddies */
order++;
freelist++;
}
page = &mem_map[idx];
links_add(&page->list, &freelist->list);
freelist->nr_pageblocks++;
SET_PAGE_FLAG(page, PAGE_BUDDY);
SET_PAGE_ORDER(page, order);
spin_unlock_irqrestore(&node->lock, irqflag);
}
struct page *alloc_pages(struct buddy *pool, unsigned int order)
{
struct buddy_freelist *freelist = &pool->free[order];
struct list *head, *curr;
struct page *page;
unsigned int i;
for (i = order; i < BUDDY_MAX_ORDER; i++, freelist++) {
head = &freelist->list;
curr = head->next;
if (curr != head) {
page = get_container_of(curr, struct page, link);
list_del(curr);
BITMAP_TOGGLE(freelist->bitmap,
PAGE_INDEX(page->addr), i);
/* if allocating from higher order, split in half to add
* one of them to current order. */
while (i > order) {
freelist--;
i--;
list_add(&page->link, &freelist->list);
BITMAP_TOGGLE(freelist->bitmap,
PAGE_INDEX(page->addr), i);
page += 1 << i;
}
pool->nr_free -= 1 << order;
SET_PAGE_ORDER(page, order);
SET_PAGE_FLAG(page, PAGE_BUDDY);
return page;
}
}