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FAILED: patch "[PATCH] mm/mm_init: fix pageblock migratetype for ZONE_DEVICE" failed to apply to 6.6-stable tree

PATCH New [email protected] 2 participants 2 messages Jul 20 – Jul 25

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Stable branch Memory management memblock and memory management initialization
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author maintainer
#0 lore raw

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 94405c6136839f7c462249c8b4b957bcb9527a9d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026072014-sincere-blooper-afaf@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 94405c6136839f7c462249c8b4b957bcb9527a9d Mon Sep 17 00:00:00 2001
From: Muchun Song <[email protected]>
Date: Tue, 28 Apr 2026 16:18:54 +0800
Subject: [PATCH] mm/mm_init: fix pageblock migratetype for ZONE_DEVICE
compound pages

The memmap_init_zone_device() function only initializes the migratetype of the first pageblock of a compound page. If the compound page size exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), subsequent pageblocks in the compound page remain uninitialized.

Move the migratetype initialization out of __init_zone_device_page() and into a separate pageblock_migratetype_init_range() function. This iterates over the entire PFN range of the memory, ensuring that all pageblocks are correctly initialized.

Also remove the stale confusing comment about MEMINIT_HOTPLUG above the migratetype setting since it is an obsolete relic from commit 966cf44f637e ("mm: defer ZONE_DEVICE page initialization to the point where we init pgmap") and no longer makes sense here.

Link https://lore.kernel.org/[email protected] open here
Fixes c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages")
Signed-off-by Muchun Song <[email protected]>
Reviewed-by Mike Rapoport (Microsoft) <[email protected]>
Reviewed-by Oscar Salvador <[email protected]>
Acked-by David Hildenbrand (Arm) <[email protected]>
Acked-by Liam R. Howlett <[email protected]>
Cc "Aneesh Kumar K.V" <[email protected]>
Cc Joao Martins <[email protected]>
Cc Lorenzo Stoakes <[email protected]>
Cc Madhavan Srinivasan <[email protected]>
Cc Michael Ellerman <[email protected]>
Cc Michal Hocko <[email protected]>
Cc Nicholas Piggin <[email protected]>
Cc Suren Baghdasaryan <[email protected]>
Cc Vlastimil Babka <[email protected]>
Cc <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
mm/mm_init.c +19 -15
index f9f8e1af921c..cfc76953e249 100644
@@ -674,6 +674,20 @@ static inline void fixup_hashdist(void)
 static inline void fixup_hashdist(void) {}
 #endif /* CONFIG_NUMA */
 
+#ifdef CONFIG_ZONE_DEVICE
+static __meminit void pageblock_migratetype_init_range(unsigned long pfn,
+		unsigned long nr_pages, int migratetype)
+{
+	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))
+			cond_resched();
+	}
+}
+#endif
+
 /*
  * Initialize a reserved page unconditionally, finding its zone first.
  */

@@ -1011,21 +1025,6 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
 	page_folio(page)->pgmap = pgmap;
 	page->zone_device_data = NULL;
 
-	/*
-	 * Mark the block movable so that blocks are reserved for
-	 * movable at startup. This will force kernel allocations
-	 * to reserve their blocks rather than leaking throughout
-	 * the address space during boot when many long-lived
-	 * kernel allocations are made.
-	 *
-	 * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
-	 * because this is done early in section_activate()
-	 */
-	if (pageblock_aligned(pfn)) {
-		init_pageblock_migratetype(page, MIGRATE_MOVABLE, false);
-		cond_resched();
-	}
-
 	/*
 	 * ZONE_DEVICE pages other than MEMORY_TYPE_GENERIC are released
 	 * directly to the driver page allocator which will set the page count

@@ -1122,6 +1121,9 @@ void __ref memmap_init_zone_device(struct zone *zone,
 
 		__init_zone_device_page(page, pfn, zone_idx, nid, pgmap);
 
+		if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
+			cond_resched();
+
 		if (pfns_per_compound == 1)
 			continue;
 

@@ -1129,6 +1131,8 @@ void __ref memmap_init_zone_device(struct zone *zone,
 				     compound_nr_pages(altmap, pgmap));
 	}
 
+	pageblock_migratetype_init_range(start_pfn, nr_pages, MIGRATE_MOVABLE);
+
 	pr_debug("%s initialised %lu pages in %ums\n", __func__,
 		nr_pages, jiffies_to_msecs(jiffies - start));
 }
maintainer
#1 lore raw

PATCH 1/1 mm/mm_init: fix pageblock migratetype for ZONE_DEVICE compound pages

From: Muchun Song <[email protected]>

[ Upstream commit 94405c6136839f7c462249c8b4b957bcb9527a9d ]

The memmap_init_zone_device() function only initializes the migratetype of the first pageblock of a compound page. If the compound page size exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks), subsequent pageblocks in the compound page remain uninitialized.

Move the migratetype initialization out of __init_zone_device_page() and into a separate pageblock_migratetype_init_range() function. This iterates over the entire PFN range of the memory, ensuring that all pageblocks are correctly initialized.

Also remove the stale confusing comment about MEMINIT_HOTPLUG above the migratetype setting since it is an obsolete relic from commit 966cf44f637e ("mm: defer ZONE_DEVICE page initialization to the point where we init pgmap") and no longer makes sense here.

Link https://lore.kernel.org/[email protected] open here
Fixes c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages")
Signed-off-by Muchun Song <[email protected]>
Reviewed-by Mike Rapoport (Microsoft) <[email protected]>
Reviewed-by Oscar Salvador <[email protected]>
Acked-by David Hildenbrand (Arm) <[email protected]>
Acked-by Liam R. Howlett <[email protected]>
Cc "Aneesh Kumar K.V" <[email protected]>
Cc Joao Martins <[email protected]>
Cc Lorenzo Stoakes <[email protected]>
Cc Madhavan Srinivasan <[email protected]>
Cc Michael Ellerman <[email protected]>
Cc Michal Hocko <[email protected]>
Cc Nicholas Piggin <[email protected]>
Cc Suren Baghdasaryan <[email protected]>
Cc Vlastimil Babka <[email protected]>
Cc <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Sasha Levin <[email protected]>
---
 mm/mm_init.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)
mm/mm_init.c +19 -15
index f9f87e2299b8f1..a71fbb3cec3870 100644
@@ -649,6 +649,20 @@ static inline void fixup_hashdist(void)
 static inline void fixup_hashdist(void) {}
 #endif /* CONFIG_NUMA */
 
+#ifdef CONFIG_ZONE_DEVICE
+static __meminit void pageblock_migratetype_init_range(unsigned long pfn,
+		unsigned long nr_pages, int migratetype)
+{
+	const unsigned long end = pfn + nr_pages;
+
+	for (pfn = pageblock_align(pfn); pfn < end; pfn += pageblock_nr_pages) {
+		set_pageblock_migratetype(pfn_to_page(pfn), migratetype);
+		if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
+			cond_resched();
+	}
+}
+#endif
+
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
 {

@@ -992,21 +1006,6 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
 	page->pgmap = pgmap;
 	page->zone_device_data = NULL;
 
-	/*
-	 * Mark the block movable so that blocks are reserved for
-	 * movable at startup. This will force kernel allocations
-	 * to reserve their blocks rather than leaking throughout
-	 * the address space during boot when many long-lived
-	 * kernel allocations are made.
-	 *
-	 * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
-	 * because this is done early in section_activate()
-	 */
-	if (pageblock_aligned(pfn)) {
-		set_pageblock_migratetype(page, MIGRATE_MOVABLE);
-		cond_resched();
-	}
-
 	/*
 	 * ZONE_DEVICE pages are released directly to the driver page allocator
 	 * which will set the page count to 1 when allocating the page.

@@ -1098,6 +1097,9 @@ void __ref memmap_init_zone_device(struct zone *zone,
 
 		__init_zone_device_page(page, pfn, zone_idx, nid, pgmap);
 
+		if (IS_ALIGNED(pfn, PAGES_PER_SECTION))
+			cond_resched();
+
 		if (pfns_per_compound == 1)
 			continue;
 

@@ -1105,6 +1107,8 @@ 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);
+
 	pr_debug("%s initialised %lu pages in %ums\n", __func__,
 		nr_pages, jiffies_to_msecs(jiffies - start));
 }
Signature · 1 line
2.53.0