[PATCH 4/4] mm: memory_hotplug: unify Huge/LRU/non-LRU movable folio isolation

[Kefeng Wang <wangkefeng.wang@huawei.com>]

Move isolate_hugetlb() after grab a reference, and use the
isolate_folio_to_list() to unify hugetlb/LRU/non-LRU folio
isolation, which cleanup code a bit and save a few calls to
compound_head().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/memory_hotplug.c | 48 +++++++++++++++------------------------------
 1 file changed, 16 insertions(+), 32 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ccaf4c480aed..057037766efa 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1773,20 +1773,17 @@ static int scan_movable_pages(unsigned long start, unsigned long end,
 static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 {
 	unsigned long pfn;
-	struct page *page, *head;
 	LIST_HEAD(source);
+	struct folio *folio;
 	static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
 				      DEFAULT_RATELIMIT_BURST);
 
 	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
-		struct folio *folio;
-		bool isolated;
+		struct page *page;
 
 		if (!pfn_valid(pfn))
 			continue;
 		page = pfn_to_page(pfn);
-		folio = page_folio(page);
-		head = &folio->page;
 
 		/*
 		 * HWPoison pages have elevated reference counts so the migration would
@@ -1808,36 +1805,22 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 			continue;
 		}
 
-		if (PageHuge(page)) {
-			pfn = page_to_pfn(head) + compound_nr(head) - 1;
-			isolate_hugetlb(folio, &source);
+		folio = folio_get_nontail_page(page);
+		if (!folio)
 			continue;
-		} else if (PageTransHuge(page))
-			pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
-
-		if (!get_page_unless_zero(page))
-			continue;
-		/*
-		 * We can skip free pages. And we can deal with pages on
-		 * LRU and non-lru movable pages.
-		 */
-		if (PageLRU(page))
-			isolated = isolate_lru_page(page);
-		else
-			isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
-		if (isolated) {
-			list_add_tail(&page->lru, &source);
-			if (!__PageMovable(page))
-				inc_node_page_state(page, NR_ISOLATED_ANON +
-						    page_is_file_lru(page));
 
-		} else {
+		/* Skip free folios, deal with hugetlb, LRU and non-lru movable folios. */
+		if (!isolate_folio_to_list(folio, &source)) {
 			if (__ratelimit(&migrate_rs)) {
 				pr_warn("failed to isolate pfn %lx\n", pfn);
 				dump_page(page, "isolation failed");
 			}
 		}
-		put_page(page);
+
+		if (folio_test_large(folio))
+			pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;
+
+		folio_put(folio);
 	}
 	if (!list_empty(&source)) {
 		nodemask_t nmask = node_states[N_MEMORY];
@@ -1852,7 +1835,7 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 		 * We have checked that migration range is on a single zone so
 		 * we can use the nid of the first page to all the others.
 		 */
-		mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
+		mtc.nid = folio_nid(list_first_entry(&source, struct folio, lru));
 
 		/*
 		 * try to allocate from a different node but reuse this node
@@ -1865,11 +1848,12 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 		ret = migrate_pages(&source, alloc_migration_target, NULL,
 			(unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
 		if (ret) {
-			list_for_each_entry(page, &source, lru) {
+			list_for_each_entry(folio, &source, lru) {
 				if (__ratelimit(&migrate_rs)) {
 					pr_warn("migrating pfn %lx failed ret:%d\n",
-						page_to_pfn(page), ret);
-					dump_page(page, "migration failure");
+						folio_pfn(folio), ret);
+					dump_page(&folio->page,
+						  "migration failure");
 				}
 			}
 			putback_movable_pages(&source);
-- 
2.27.0