内存管理之bootmem管理之释放所有bootmem内存

主要是提供__free_pages_boot_core()函数，对外提供__free_pages_bootmem()和deferred_free_range()

__free_pages_bootmem()

1. free_bootmem_late

2. free_all_bootmem_core  《<-- free_all_bootmem》

3. __memblock_free_late

/*
 * free_bootmem_late - free bootmem pages directly to page allocator
 * @addr: starting physical address of the range
 * @size: size of the range in bytes
 *
 * This is only useful when the bootmem allocator has already been torn
 * down, but we are still initializing the system.  Pages are given directly
 * to the page allocator, no bootmem metadata is updated because it is gone.
 */
void __init free_bootmem_late(unsigned long physaddr, unsigned long size)
{
unsigned long cursor, end;

kmemleak_free_part_phys(physaddr, size);

cursor = PFN_UP(physaddr);
end = PFN_DOWN(physaddr + size);

for (; cursor < end; cursor++) {
__free_pages_bootmem(pfn_to_page(cursor), cursor, 0);
totalram_pages++;
}
}

static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
{
struct page *page;
unsigned long *map, start, end, pages, cur, count = 0;

if (!bdata->node_bootmem_map)
return 0;

map = bdata->node_bootmem_map;
start = bdata->node_min_pfn;
end = bdata->node_low_pfn;

bdebug("nid=%td start=%lx end=%lx\n",
bdata - bootmem_node_data, start, end);

while (start < end) {
unsigned long idx, vec;
unsigned shift;

idx = start - bdata->node_min_pfn;
shift = idx & (BITS_PER_LONG - 1);
/*
* vec holds at most BITS_PER_LONG map bits,
* bit 0 corresponds to start.
*/
vec = ~map[idx / BITS_PER_LONG];

if (shift) {
vec >>= shift;
if (end - start >= BITS_PER_LONG)
vec |= ~map[idx / BITS_PER_LONG + 1] <<
(BITS_PER_LONG - shift);
}
/*
* If we have a properly aligned and fully unreserved
* BITS_PER_LONG block of pages in front of us, free
* it in one go.
*/
if (IS_ALIGNED(start, BITS_PER_LONG) && vec == ~0UL) {
int order = ilog2(BITS_PER_LONG);

__free_pages_bootmem(pfn_to_page(start), start, order);
count += BITS_PER_LONG;
start += BITS_PER_LONG;
} else {
cur = start;

start = ALIGN(start + 1, BITS_PER_LONG);
while (vec && cur != start) {
if (vec & 1) {
page = pfn_to_page(cur);
__free_pages_bootmem(page, cur, 0);
count++;
}
vec >>= 1;
++cur;
}
}
}

cur = bdata->node_min_pfn;
page = virt_to_page(bdata->node_bootmem_map);
pages = bdata->node_low_pfn - bdata->node_min_pfn;
pages = bootmem_bootmap_pages(pages);
count += pages;
while (pages--)
__free_pages_bootmem(page++, cur++, 0);
bdata->node_bootmem_map = NULL;
bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);
return count;
}