/*
* start_isolate_page_range() -- make page-allocation-type of range of pages
* to be MIGRATE_ISOLATE.
* @start_pfn: The lower PFN of the range to be isolated.
* @end_pfn: The upper PFN of the range to be isolated.
* @migratetype: migrate type to set in error recovery.
*
* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
* the range will never be allocated. Any free pages and pages freed in the
* future will not be allocated again.
*
* start_pfn/end_pfn must be aligned to pageblock_order.
* Returns 0 on success and -EBUSY if any part of range cannot be isolated.
*/
int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned migratetype, bool skip_hwpoisoned_pages)
{
unsigned long pfn;
unsigned long undo_pfn;
struct page *page;
BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
for (pfn = start_pfn;
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (page &&
set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
undo_pfn = pfn;
goto undo;
}
}
return 0;
undo:
for (pfn = start_pfn;
pfn < undo_pfn;
pfn += pageblock_nr_pages)
unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
return -EBUSY;
}
/*
* start_isolate_page_range() -- make page-allocation-type of range of pages
* to be MIGRATE_ISOLATE.
* @start_pfn: The lower PFN of the range to be isolated.
* @end_pfn: The upper PFN of the range to be isolated.
*
* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
* the range will never be allocated. Any free pages and pages freed in the
* future will not be allocated again.
*
* start_pfn/end_pfn must be aligned to pageblock_order.
* Returns 0 on success and -EBUSY if any part of range cannot be isolated.
*/
int
start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long pfn;
unsigned long undo_pfn;
struct page *page;
BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
for (pfn = start_pfn;
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (page && set_migratetype_isolate(page)) {
undo_pfn = pfn;
goto undo;
}
}
return 0;
undo:
for (pfn = start_pfn;
pfn < undo_pfn;
pfn += pageblock_nr_pages)
unset_migratetype_isolate(pfn_to_page(pfn));
return -EBUSY;
}
/**
* Claim a given page from the buddy subsystem. This only works, if the page registered within the buddy system and marked as free
*
*/
int
try_claim_free_buddy_page(struct page* requested_page,
unsigned int allowed_sources, struct page** allocated_page,
unsigned long* actual_source) {
int ret = CLAIMED_TRY_NEXT;
if (allowed_sources & SOURCE_FREE_BUDDY_PAGE) {
struct page * locked_page = NULL;
unsigned long pfn = page_to_pfn(requested_page);
unsigned int locked_page_count_after, locked_page_count_before;
/*
* Isolate the page, so that it doesn't get reallocated if it
* was free.
*/
set_migratetype_isolate(requested_page);
locked_page_count_before = page_count(requested_page);
if (0 == page_count(compound_head(requested_page))) {
if (is_free_buddy_page(requested_page)) {
printk(KERN_DEBUG "try_claim_free_buddy_page: %#lx free buddy page\n", pfn);
/* get, while page is still isolated */
locked_page = claim_free_buddy_page(requested_page);
} else {
printk(KERN_DEBUG
"try_claim_free_buddy_page: %#lx: unknown zero refcount page type %lx\n",
pfn, requested_page->flags);
}
} else {
long cppfn = page_to_pfn(compound_head(requested_page));
/* Not a free page */
printk(KERN_DEBUG
"try_claim_free_buddy_page: %#lx: %#lx refcount %i ,page type %lx\n",
pfn, cppfn, page_count(compound_head(requested_page)), requested_page->flags);
}
unset_migratetype_isolate(requested_page);
if (locked_page) {
/*
* The page is now rightfully ours!
*/
locked_page_count_after = page_count(locked_page);
printk(KERN_DEBUG "Buddy: Requested pfn %lx, allocated pfn %lx with pagecount %i (was:%i)\n", page_to_pfn(requested_page), page_to_pfn(locked_page), locked_page_count_after, locked_page_count_before);
*actual_source = SOURCE_FREE_BUDDY_PAGE;
ret = CLAIMED_SUCCESSFULLY;
}
}
return ret;
}
/*
* Make isolated pages available again.
*/
int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned migratetype)
{
unsigned long pfn;
struct page *page;
BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
for (pfn = start_pfn;
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
continue;
unset_migratetype_isolate(page, migratetype);
}
return 0;
}
/*
* Make isolated pages available again.
*/
int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned migratetype)
{
unsigned long pfn;
struct page *page;
BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
for (pfn = start_pfn;
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (!page || !is_migrate_isolate_page(page))
continue;
unset_migratetype_isolate(page, migratetype);
}
return 0;
}
