[PATCH v4 16/21] mm/mm_init: simplify deferred_free_pages() migratetype init

[Pratyush Yadav <pratyush@kernel.org>]

From: Muchun Song <songmuchun@bytedance.com>

deferred_free_pages() open-codes two loops to initialize the pageblock
migratetype for a range of pages.

Replace them with pageblock_migratetype_init_range() to remove the
duplication and make the code clearer (Note that deferred_free_pages() may
be called from atomic context).

Link: https://lore.kernel.org/20260612035903.2468601-6-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
---

Notes:
    This patch is taken from Muchun's series [0]. The patch as of today is
    in mm-unstable.
    
    [0] https://lore.kernel.org/linux-mm/20260612035903.2468601-6-songmuchun@bytedance.com/

 mm/mm_init.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 84d4b1c997bc..30355effe1f2 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -674,15 +674,15 @@ static inline void fixup_hashdist(void)
 static inline void fixup_hashdist(void) {}
 #endif /* CONFIG_NUMA */
 
-#ifdef CONFIG_ZONE_DEVICE
+#if defined(CONFIG_ZONE_DEVICE) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
 static __meminit void pageblock_migratetype_init_range(unsigned long pfn,
-		unsigned long nr_pages, int migratetype)
+		unsigned long nr_pages, int migratetype, bool atomic)
 {
 	const unsigned long end = pfn + nr_pages;
 
 	for (pfn = pageblock_align(pfn); pfn < end; pfn += pageblock_nr_pages) {
 		init_pageblock_migratetype(pfn_to_page(pfn), migratetype, false);
-		if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
+		if (!atomic && IS_ALIGNED(pfn, PAGES_PER_SECTION))
 			cond_resched();
 	}
 }
@@ -1142,7 +1142,7 @@ void __ref memmap_init_zone_device(struct zone *zone,
 				     compound_nr_pages(pfn, altmap, pgmap));
 	}
 
-	pageblock_migratetype_init_range(start_pfn, nr_pages, MIGRATE_MOVABLE);
+	pageblock_migratetype_init_range(start_pfn, nr_pages, MIGRATE_MOVABLE, false);
 
 	pr_debug("%s initialised %lu pages in %ums\n", __func__,
 		nr_pages, jiffies_to_msecs(jiffies - start));
@@ -1981,12 +1981,12 @@ static void __init deferred_free_pages(unsigned long pfn,
 	if (!nr_pages)
 		return;
 
+	pageblock_migratetype_init_range(pfn, nr_pages, mt, true);
+
 	page = pfn_to_page(pfn);
 
 	/* Free a large naturally-aligned chunk if possible */
 	if (nr_pages == MAX_ORDER_NR_PAGES && IS_MAX_ORDER_ALIGNED(pfn)) {
-		for (i = 0; i < nr_pages; i += pageblock_nr_pages)
-			init_pageblock_migratetype(page + i, mt, false);
 		__free_pages_core(page, MAX_PAGE_ORDER, MEMINIT_EARLY);
 		return;
 	}
@@ -1994,11 +1994,8 @@ static void __init deferred_free_pages(unsigned long pfn,
 	/* Accept chunks smaller than MAX_PAGE_ORDER upfront */
 	accept_memory(PFN_PHYS(pfn), nr_pages * PAGE_SIZE);
 
-	for (i = 0; i < nr_pages; i++, page++, pfn++) {
-		if (pageblock_aligned(pfn))
-			init_pageblock_migratetype(page, mt, false);
-		__free_pages_core(page, 0, MEMINIT_EARLY);
-	}
+	for (i = 0; i < nr_pages; i++)
+		__free_pages_core(page + i, 0, MEMINIT_EARLY);
 }
 
 /* Completion tracking for deferred_init_memmap() threads */
-- 
2.55.0.229.g6434b31f56-goog