[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / page_isolation.c

/*
 * linux/mm/page_isolation.c
 */

#include <linux/mm.h>
#include <linux/page-isolation.h>
#include <linux/pageblock-flags.h>
#include <linux/memory.h>
#include "internal.h"

int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages)
{
	struct zone *zone;
	unsigned long flags, pfn;
	struct memory_isolate_notify arg;
	int notifier_ret;
	int ret = -EBUSY;

	zone = page_zone(page);

	spin_lock_irqsave(&zone->lock, flags);

	pfn = page_to_pfn(page);
	arg.start_pfn = pfn;
	arg.nr_pages = pageblock_nr_pages;
	arg.pages_found = 0;

	/*
	 * It may be possible to isolate a pageblock even if the
	 * migratetype is not MIGRATE_MOVABLE. The memory isolation
	 * notifier chain is used by balloon drivers to return the
	 * number of pages in a range that are held by the balloon
	 * driver to shrink memory. If all the pages are accounted for
	 * by balloons, are free, or on the LRU, isolation can continue.
	 * Later, for example, when memory hotplug notifier runs, these
	 * pages reported as "can be isolated" should be isolated(freed)
	 * by the balloon driver through the memory notifier chain.
	 */
	notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
	notifier_ret = notifier_to_errno(notifier_ret);
	if (notifier_ret)
		goto out;
	/*
	 * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
	 * We just check MOVABLE pages.
	 */
	if (!has_unmovable_pages(zone, page, arg.pages_found,
				 skip_hwpoisoned_pages))
		ret = 0;

	/*
	 * immobile means "not-on-lru" paes. If immobile is larger than
	 * removable-by-driver pages reported by notifier, we'll fail.
	 */

out:
	if (!ret) {
		unsigned long nr_pages;
		int migratetype = get_pageblock_migratetype(page);

		set_pageblock_migratetype(page, MIGRATE_ISOLATE);
		nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);

		__mod_zone_freepage_state(zone, -nr_pages, migratetype);
	}

	spin_unlock_irqrestore(&zone->lock, flags);
	if (!ret)
		drain_all_pages();
	return ret;
}

void unset_migratetype_isolate(struct page *page, unsigned migratetype)
{
	struct zone *zone;
	unsigned long flags, nr_pages;

	zone = page_zone(page);
	spin_lock_irqsave(&zone->lock, flags);
	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
		goto out;
	nr_pages = move_freepages_block(zone, page, migratetype);
	__mod_zone_freepage_state(zone, nr_pages, migratetype);
	set_pageblock_migratetype(page, migratetype);
out:
	spin_unlock_irqrestore(&zone->lock, flags);
}

static inline struct page *
__first_valid_page(unsigned long pfn, unsigned long nr_pages)
{
	int i;
	for (i = 0; i < nr_pages; i++)
		if (pfn_valid_within(pfn + i))
			break;
	if (unlikely(i == nr_pages))
		return NULL;
	return pfn_to_page(pfn + i);
}

/*
 * 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((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, 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;
}

/*
 * 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;
}
/*
 * Test all pages in the range is free(means isolated) or not.
 * all pages in [start_pfn...end_pfn) must be in the same zone.
 * zone->lock must be held before call this.
 *
 * Returns 1 if all pages in the range are isolated.
 */
static int
__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
				  bool skip_hwpoisoned_pages)
{
	struct page *page;

	while (pfn < end_pfn) {
		if (!pfn_valid_within(pfn)) {
			pfn++;
			continue;
		}
		page = pfn_to_page(pfn);
		if (PageBuddy(page)) {
			/*
			 * If race between isolatation and allocation happens,
			 * some free pages could be in MIGRATE_MOVABLE list
			 * although pageblock's migratation type of the page
			 * is MIGRATE_ISOLATE. Catch it and move the page into
			 * MIGRATE_ISOLATE list.
			 */
			if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) {
				struct page *end_page;

				end_page = page + (1 << page_order(page)) - 1;
				move_freepages(page_zone(page), page, end_page,
						MIGRATE_ISOLATE);
			}
			pfn += 1 << page_order(page);
		}
		else if (page_count(page) == 0 &&
			get_freepage_migratetype(page) == MIGRATE_ISOLATE)
			pfn += 1;
		else if (skip_hwpoisoned_pages && PageHWPoison(page)) {
			/*
			 * The HWPoisoned page may be not in buddy
			 * system, and page_count() is not 0.
			 */
			pfn++;
			continue;
		}
		else
			break;
	}
	if (pfn < end_pfn)
		return 0;
	return 1;
}

int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
			bool skip_hwpoisoned_pages)
{
	unsigned long pfn, flags;
	struct page *page;
	struct zone *zone;
	int ret;

	/*
	 * Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page
	 * is not aligned to pageblock_nr_pages.
	 * Then we just check pagetype fist.
	 */
	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)
			break;
	}
	page = __first_valid_page(start_pfn, end_pfn - start_pfn);
	if ((pfn < end_pfn) || !page)
		return -EBUSY;
	/* Check all pages are free or Marked as ISOLATED */
	zone = page_zone(page);
	spin_lock_irqsave(&zone->lock, flags);
	ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
						skip_hwpoisoned_pages);
	spin_unlock_irqrestore(&zone->lock, flags);
	return ret ? 0 : -EBUSY;
}

struct page *alloc_migrate_target(struct page *page, unsigned long private,
				  int **resultp)
{
	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;

	if (PageHighMem(page))
		gfp_mask |= __GFP_HIGHMEM;

	return alloc_page(gfp_mask);
}
Commit	Line	Data
a5d76b54 KH	1	/*
	2	* linux/mm/page_isolation.c
	3	*/
	4
a5d76b54 KH	5	#include <linux/mm.h>
	6	#include <linux/page-isolation.h>
	7	#include <linux/pageblock-flags.h>
ee6f509c	8	#include <linux/memory.h>
a5d76b54 KH	9	#include "internal.h"
a5d76b54 KH	10
b023f468	11	int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages)
ee6f509c MK	12	{
	13	struct zone *zone;
	14	unsigned long flags, pfn;
	15	struct memory_isolate_notify arg;
	16	int notifier_ret;
	17	int ret = -EBUSY;
	18
	19	zone = page_zone(page);
	20
	21	spin_lock_irqsave(&zone->lock, flags);
	22
	23	pfn = page_to_pfn(page);
	24	arg.start_pfn = pfn;
	25	arg.nr_pages = pageblock_nr_pages;
	26	arg.pages_found = 0;
	27
	28	/*
	29	* It may be possible to isolate a pageblock even if the
	30	* migratetype is not MIGRATE_MOVABLE. The memory isolation
	31	* notifier chain is used by balloon drivers to return the
	32	* number of pages in a range that are held by the balloon
	33	* driver to shrink memory. If all the pages are accounted for
	34	* by balloons, are free, or on the LRU, isolation can continue.
	35	* Later, for example, when memory hotplug notifier runs, these
	36	* pages reported as "can be isolated" should be isolated(freed)
	37	* by the balloon driver through the memory notifier chain.
	38	*/
	39	notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
	40	notifier_ret = notifier_to_errno(notifier_ret);
	41	if (notifier_ret)
	42	goto out;
	43	/*
	44	* FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
	45	* We just check MOVABLE pages.
	46	*/
b023f468 WC	47	if (!has_unmovable_pages(zone, page, arg.pages_found,
b023f468 WC	48	skip_hwpoisoned_pages))
ee6f509c MK	49	ret = 0;
	50
	51	/*
	52	* immobile means "not-on-lru" paes. If immobile is larger than
	53	* removable-by-driver pages reported by notifier, we'll fail.
	54	*/
	55
	56	out:
	57	if (!ret) {
2139cbe6	58	unsigned long nr_pages;
d1ce749a	59	int migratetype = get_pageblock_migratetype(page);
2139cbe6	60
a458431e	61	set_pageblock_migratetype(page, MIGRATE_ISOLATE);
2139cbe6 BZ	62	nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
2139cbe6 BZ	63
d1ce749a	64	__mod_zone_freepage_state(zone, -nr_pages, migratetype);
ee6f509c MK	65	}
	66
	67	spin_unlock_irqrestore(&zone->lock, flags);
	68	if (!ret)
	69	drain_all_pages();
	70	return ret;
	71	}
	72
	73	void unset_migratetype_isolate(struct page *page, unsigned migratetype)
	74	{
	75	struct zone *zone;
2139cbe6 BZ	76	unsigned long flags, nr_pages;
2139cbe6 BZ	77
ee6f509c MK	78	zone = page_zone(page);
	79	spin_lock_irqsave(&zone->lock, flags);
	80	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
	81	goto out;
2139cbe6	82	nr_pages = move_freepages_block(zone, page, migratetype);
d1ce749a	83	__mod_zone_freepage_state(zone, nr_pages, migratetype);
a458431e	84	set_pageblock_migratetype(page, migratetype);
ee6f509c MK	85	out:
	86	spin_unlock_irqrestore(&zone->lock, flags);
	87	}
	88
a5d76b54 KH	89	static inline struct page *
	90	__first_valid_page(unsigned long pfn, unsigned long nr_pages)
	91	{
	92	int i;
	93	for (i = 0; i < nr_pages; i++)
	94	if (pfn_valid_within(pfn + i))
	95	break;
	96	if (unlikely(i == nr_pages))
	97	return NULL;
	98	return pfn_to_page(pfn + i);
	99	}
	100
	101	/*
	102	* start_isolate_page_range() -- make page-allocation-type of range of pages
	103	* to be MIGRATE_ISOLATE.
	104	* @start_pfn: The lower PFN of the range to be isolated.
	105	* @end_pfn: The upper PFN of the range to be isolated.
0815f3d8	106	* @migratetype: migrate type to set in error recovery.
a5d76b54 KH	107	*
	108	* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
	109	* the range will never be allocated. Any free pages and pages freed in the
	110	* future will not be allocated again.
	111	*
	112	* start_pfn/end_pfn must be aligned to pageblock_order.
	113	* Returns 0 on success and -EBUSY if any part of range cannot be isolated.
	114	*/
0815f3d8	115	int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
b023f468	116	unsigned migratetype, bool skip_hwpoisoned_pages)
a5d76b54 KH	117	{
	118	unsigned long pfn;
	119	unsigned long undo_pfn;
	120	struct page *page;
	121
	122	BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
	123	BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
	124
	125	for (pfn = start_pfn;
	126	pfn < end_pfn;
	127	pfn += pageblock_nr_pages) {
	128	page = __first_valid_page(pfn, pageblock_nr_pages);
b023f468 WC	129	if (page &&
b023f468 WC	130	set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
a5d76b54 KH	131	undo_pfn = pfn;
	132	goto undo;
	133	}
	134	}
	135	return 0;
	136	undo:
	137	for (pfn = start_pfn;
dbc0e4ce	138	pfn < undo_pfn;
a5d76b54	139	pfn += pageblock_nr_pages)
0815f3d8	140	unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
a5d76b54 KH	141
	142	return -EBUSY;
	143	}
	144
	145	/*
	146	* Make isolated pages available again.
	147	*/
0815f3d8 MN	148	int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
0815f3d8 MN	149	unsigned migratetype)
a5d76b54 KH	150	{
	151	unsigned long pfn;
	152	struct page *page;
	153	BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
	154	BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
	155	for (pfn = start_pfn;
	156	pfn < end_pfn;
	157	pfn += pageblock_nr_pages) {
	158	page = __first_valid_page(pfn, pageblock_nr_pages);
dbc0e4ce	159	if (!page \|\| get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
a5d76b54	160	continue;
0815f3d8	161	unset_migratetype_isolate(page, migratetype);
a5d76b54 KH	162	}
	163	return 0;
	164	}
	165	/*
	166	* Test all pages in the range is free(means isolated) or not.
	167	* all pages in [start_pfn...end_pfn) must be in the same zone.
	168	* zone->lock must be held before call this.
	169	*
0815f3d8	170	* Returns 1 if all pages in the range are isolated.
a5d76b54 KH	171	*/
a5d76b54 KH	172	static int
b023f468 WC	173	__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
b023f468 WC	174	bool skip_hwpoisoned_pages)
a5d76b54 KH	175	{
	176	struct page *page;
	177
	178	while (pfn < end_pfn) {
	179	if (!pfn_valid_within(pfn)) {
	180	pfn++;
	181	continue;
	182	}
	183	page = pfn_to_page(pfn);
41d575ad	184	if (PageBuddy(page)) {
435b405c MK	185	/*
	186	* If race between isolatation and allocation happens,
	187	* some free pages could be in MIGRATE_MOVABLE list
	188	* although pageblock's migratation type of the page
	189	* is MIGRATE_ISOLATE. Catch it and move the page into
	190	* MIGRATE_ISOLATE list.
	191	*/
	192	if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) {
	193	struct page *end_page;
	194
	195	end_page = page + (1 << page_order(page)) - 1;
	196	move_freepages(page_zone(page), page, end_page,
	197	MIGRATE_ISOLATE);
	198	}
a5d76b54	199	pfn += 1 << page_order(page);
41d575ad	200	}
a5d76b54	201	else if (page_count(page) == 0 &&
b12c4ad1	202	get_freepage_migratetype(page) == MIGRATE_ISOLATE)
a5d76b54	203	pfn += 1;
b023f468 WC	204	else if (skip_hwpoisoned_pages && PageHWPoison(page)) {
	205	/*
	206	* The HWPoisoned page may be not in buddy
	207	* system, and page_count() is not 0.
	208	*/
	209	pfn++;
	210	continue;
	211	}
a5d76b54 KH	212	else
	213	break;
	214	}
	215	if (pfn < end_pfn)
	216	return 0;
	217	return 1;
	218	}
	219
b023f468 WC	220	int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
b023f468 WC	221	bool skip_hwpoisoned_pages)
a5d76b54	222	{
6c1b7f68	223	unsigned long pfn, flags;
a5d76b54	224	struct page *page;
6c1b7f68 GS	225	struct zone *zone;
6c1b7f68 GS	226	int ret;
a5d76b54	227
a5d76b54 KH	228	/*
	229	* Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page
	230	* is not aligned to pageblock_nr_pages.
	231	* Then we just check pagetype fist.
	232	*/
	233	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
	234	page = __first_valid_page(pfn, pageblock_nr_pages);
dbc0e4ce	235	if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
a5d76b54 KH	236	break;
a5d76b54 KH	237	}
a70dcb96 GS	238	page = __first_valid_page(start_pfn, end_pfn - start_pfn);
a70dcb96 GS	239	if ((pfn < end_pfn) \|\| !page)
a5d76b54 KH	240	return -EBUSY;
a5d76b54 KH	241	/* Check all pages are free or Marked as ISOLATED */
a70dcb96	242	zone = page_zone(page);
6c1b7f68	243	spin_lock_irqsave(&zone->lock, flags);
b023f468 WC	244	ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
b023f468 WC	245	skip_hwpoisoned_pages);
6c1b7f68 GS	246	spin_unlock_irqrestore(&zone->lock, flags);
6c1b7f68 GS	247	return ret ? 0 : -EBUSY;
a5d76b54	248	}
723a0644 MK	249
	250	struct page alloc_migrate_target(struct page page, unsigned long private,
	251	int **resultp)
	252	{
	253	gfp_t gfp_mask = GFP_USER \| __GFP_MOVABLE;
	254
	255	if (PageHighMem(page))
	256	gfp_mask \|= __GFP_HIGHMEM;
	257
	258	return alloc_page(gfp_mask);
	259	}