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Commit 0efadf48 authored by Yisheng Xie's avatar Yisheng Xie Committed by Linus Torvalds
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mm/hotplug: enable memory hotplug for non-lru movable pages 



We had considered all of the non-lru pages as unmovable before commit
bda807d4 ("mm: migrate: support non-lru movable page migration").
But now some of non-lru pages like zsmalloc, virtio-balloon pages also
become movable.  So we can offline such blocks by using non-lru page
migration.

This patch straightforwardly adds non-lru migration code, which means
adding non-lru related code to the functions which scan over pfn and
collect pages to be migrated and isolate them before migration.

Signed-off-by: default avatarYisheng Xie <xieyisheng1@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 85fbe5d1

mm/memory_hotplug.c

+17 −11
Original line number Diff line number Diff line
@@ -1531,10 +1531,10 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, 
}



/*

 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages

 * and hugepages). We scan pfn because it's much easier than scanning over

 * linked list. This function returns the pfn of the first found movable

 * page if it's found, otherwise 0.

 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,

 * non-lru movable pages and hugepages). We scan pfn because it's much

 * easier than scanning over linked list. This function returns the pfn

 * of the first found movable page if it's found, otherwise 0.

 */

static unsigned long scan_movable_pages(unsigned long start, unsigned long end)

{
@@ -1545,6 +1545,8 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) 
			page = pfn_to_page(pfn);

			if (PageLRU(page))

				return pfn;

			if (__PageMovable(page))

				return pfn;

			if (PageHuge(page)) {

				if (page_huge_active(page))

					return pfn;
@@ -1621,21 +1623,25 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 
		if (!get_page_unless_zero(page))

			continue;

		/*

		 * We can skip free pages. And we can only deal with pages on

		 * LRU.

		 * We can skip free pages. And we can deal with pages on

		 * LRU and non-lru movable pages.

		 */

		if (PageLRU(page))

			ret = isolate_lru_page(page);

		else

			ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);

		if (!ret) { /* Success */

			put_page(page);

			list_add_tail(&page->lru, &source);

			move_pages--;

			if (!__PageMovable(page))

				inc_node_page_state(page, NR_ISOLATED_ANON +

						    page_is_file_cache(page));



		} else {

#ifdef CONFIG_DEBUG_VM

			pr_alert("removing pfn %lx from LRU failed\n", pfn);

			dump_page(page, "failed to remove from LRU");

			pr_alert("failed to isolate pfn %lx\n", pfn);

			dump_page(page, "isolation failed");

#endif

			put_page(page);

			/* Because we don't have big zone->lock. we should

mm/page_alloc.c

+6 −2
Original line number Diff line number Diff line
@@ -7227,8 +7227,9 @@ void *__init alloc_large_system_hash(const char *tablename, 
 * If @count is not zero, it is okay to include less @count unmovable pages

 *

 * PageLRU check without isolation or lru_lock could race so that

 * MIGRATE_MOVABLE block might include unmovable pages. It means you can't

 * expect this function should be exact.

 * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable

 * check without lock_page also may miss some movable non-lru pages at

 * race condition. So you can't expect this function should be exact.

 */

bool has_unmovable_pages(struct zone *zone, struct page *page, int count,

			 bool skip_hwpoisoned_pages)
@@ -7284,6 +7285,9 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, 
		if (skip_hwpoisoned_pages && PageHWPoison(page))

			continue;



		if (__PageMovable(page))

			continue;



		if (!PageLRU(page))

			found++;

		/*