Re: [PATCH v3 4/4] mm/page_isolation: remove migratetype parameter from more functions.

[Zi Yan <ziy@nvidia.com>]

On 8 May 2025, at 16:25, Zi Yan wrote:

> On 7 May 2025, at 17:10, Zi Yan wrote:
>
>> migratetype is no longer overwritten during pageblock isolation,
>> start_isolate_page_range(), has_unmovable_pages(), and
>> set_migratetype_isolate() no longer need which migratetype to restore
>> during isolation failure.
>>
>> For has_unmoable_pages(), it needs to know if the isolation is for CMA
>> allocation, so adding CMA_ALLOCATION to isolation flags to provide the
>> information.
>>
>> alloc_contig_range() no longer needs migratetype. Replace it with
>> a newly defined acr_flags_t to tell if an allocation is for CMA. So does
>> __alloc_contig_migrate_range().
>>
>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>> ---
>>  drivers/virtio/virtio_mem.c    |  3 +--
>>  include/linux/gfp.h            |  6 +++++-
>>  include/linux/page-isolation.h | 15 +++++++++++---
>>  include/trace/events/kmem.h    | 14 +++++++------
>>  mm/cma.c                       |  2 +-
>>  mm/memory_hotplug.c            |  1 -
>>  mm/page_alloc.c                | 22 ++++++++++-----------
>>  mm/page_isolation.c            | 36 ++++++++++++----------------------
>>  8 files changed, 50 insertions(+), 49 deletions(-)
>
> Here is the fixup 3/3 to address the type issue reported by kernel test robot.
>
> From 3c439f1f09b03c8362b43c0ac05e5f174f1a6655 Mon Sep 17 00:00:00 2001
> From: Zi Yan <ziy@nvidia.com>
> Date: Thu, 8 May 2025 15:42:18 -0400
> Subject: [PATCH] fixup for mm/page_isolation: remove migratetype parameter
>  from more functions.
>
> 1. fixed test_pages_isolated() and __test_page_isolated_in_pageblock()
>    signature by using the new isol_flags_t type.
> 2. fixed test_pages_isolated() doc: flags -> isol_flags
>
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
>  include/linux/page-isolation.h | 2 +-
>  mm/page_isolation.c            | 6 +++---
>  2 files changed, 4 insertions(+), 4 deletions(-)

This is the second round of fixup 1/1 to address Johannes' comment on Patch 4.

From 760c00e808c74d62e8d879f281f38d6608c89296 Mon Sep 17 00:00:00 2001
From: Zi Yan <ziy@nvidia.com>
Date: Thu, 8 May 2025 20:54:40 -0400
Subject: [PATCH] fixup for fixup for mm/page_isolation: remove migratetype
 parameter from more functions.

1. change MEMORY_OFFLINE and CMA_ALLOCATION to isolate_mode_t enums.
2. rename isol_flags_t to isolate_flags_t.
2. REPORT_FAILURE becomes the only isolate_flags_t.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 include/linux/page-isolation.h | 26 +++++++++++++++++---------
 mm/memory_hotplug.c            |  2 +-
 mm/page_alloc.c                |  3 ++-
 mm/page_isolation.c            | 31 ++++++++++++++++++-------------
 4 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index 20c3f98b5afb..29b4ddcaea7a 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -22,17 +22,25 @@ static inline bool is_migrate_isolate(int migratetype)
 }
 #endif

+/*
+ * Isolation modes:
+ * ISOLATE_MODE_NONE - isolate for other purposes than those below
+ * MEMORY_OFFLINE    - isolate to offline (!allocate) memory e.g., skip over
+ *		       PageHWPoison() pages and PageOffline() pages.
+ * CMA_ALLOCATION    - isolate for CMA allocations
+ */
+enum isolate_mode_t {
+	ISOLATE_MODE_NONE,
+	MEMORY_OFFLINE,
+	CMA_ALLOCATION,
+};
+
 /*
  * Isolation flags:
- * MEMORY_OFFLINE - isolate to offline (!allocate) memory e.g., skip over
- *		    PageHWPoison() pages and PageOffline() pages.
  * REPORT_FAILURE - report details about the failure to isolate the range
- * CMA_ALLOCATION - isolate for CMA allocations
  */
-typedef unsigned int __bitwise isol_flags_t;
-#define MEMORY_OFFLINE		((__force isol_flags_t)BIT(0))
-#define REPORT_FAILURE		((__force isol_flags_t)BIT(1))
-#define CMA_ALLOCATION		((__force isol_flags_t)BIT(2))
+typedef unsigned int __bitwise isolate_flags_t;
+#define REPORT_FAILURE		((__force isolate_flags_t)BIT(0))

 void set_pageblock_migratetype(struct page *page, int migratetype);

@@ -40,10 +48,10 @@ bool pageblock_isolate_and_move_free_pages(struct zone *zone, struct page *page)
 bool pageblock_unisolate_and_move_free_pages(struct zone *zone, struct page *page);

 int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
-			     isol_flags_t flags);
+			     isolate_mode_t mode, isolate_flags_t flags);

 void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);

 int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
-			isol_flags_t isol_flags);
+			isolate_flags_t isol_flags);
 #endif
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 155f0b4ff299..3dab006a537e 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -2005,7 +2005,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages,

 	/* set above range as isolated */
 	ret = start_isolate_page_range(start_pfn, end_pfn,
-				       MEMORY_OFFLINE | REPORT_FAILURE);
+				       MEMORY_OFFLINE, REPORT_FAILURE);
 	if (ret) {
 		reason = "failure to isolate range";
 		goto failed_removal_pcplists_disabled;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 51d66f86b93d..3f208f8656f4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6787,7 +6787,8 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end,
 	 */

 	ret = start_isolate_page_range(start, end,
-			(alloc_flags & ACR_CMA) ? CMA_ALLOCATION : 0);
+		(alloc_flags & ACR_CMA) ? CMA_ALLOCATION : ISOLATE_MODE_NONE,
+		0);
 	if (ret)
 		goto done;

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 5f00d7113766..fd4818862654 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -48,7 +48,7 @@ static inline void set_pageblock_isolate(struct page *page)
  *
  */
 static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long end_pfn,
-				isol_flags_t flags)
+				isolate_mode_t mode, isolate_flags_t flags)
 {
 	struct page *page = pfn_to_page(start_pfn);
 	struct zone *zone = page_zone(page);
@@ -63,7 +63,7 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
 		 * isolate CMA pageblocks even when they are not movable in fact
 		 * so consider them movable here.
 		 */
-		if (flags & CMA_ALLOCATION)
+		if (mode == CMA_ALLOCATION)
 			return NULL;

 		return page;
@@ -168,8 +168,9 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
  * present in [start_pfn, end_pfn). The pageblock must intersect with
  * [start_pfn, end_pfn).
  */
-static int set_migratetype_isolate(struct page *page, isol_flags_t isol_flags,
-			unsigned long start_pfn, unsigned long end_pfn)
+static int set_migratetype_isolate(struct page *page, isolate_mode_t mode,
+			isolate_flags_t isol_flags, unsigned long start_pfn,
+			unsigned long end_pfn)
 {
 	struct zone *zone = page_zone(page);
 	struct page *unmovable;
@@ -203,7 +204,7 @@ static int set_migratetype_isolate(struct page *page, isol_flags_t isol_flags,
 				  end_pfn);

 	unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
-			isol_flags);
+			mode, isol_flags);
 	if (!unmovable) {
 		if (!pageblock_isolate_and_move_free_pages(zone, page)) {
 			spin_unlock_irqrestore(&zone->lock, flags);
@@ -309,6 +310,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  * isolate_single_pageblock() -- tries to isolate a pageblock that might be
  * within a free or in-use page.
  * @boundary_pfn:		pageblock-aligned pfn that a page might cross
+ * @mode:			isolation mode
  * @flags:			isolation flags
  * @isolate_before:	isolate the pageblock before the boundary_pfn
  * @skip_isolation:	the flag to skip the pageblock isolation in second
@@ -327,7 +329,8 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  * either. The function handles this by splitting the free page or migrating
  * the in-use page then splitting the free page.
  */
-static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t flags,
+static int isolate_single_pageblock(unsigned long boundary_pfn,
+			isolate_mode_t mode, isolate_flags_t flags,
 			bool isolate_before, bool skip_isolation)
 {
 	unsigned long start_pfn;
@@ -357,7 +360,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t fla
 		VM_BUG_ON(!get_pageblock_isolate(pfn_to_page(isolate_pageblock)));
 	} else {
 		ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock),
-				flags, isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
+				mode, flags, isolate_pageblock,
+				isolate_pageblock + pageblock_nr_pages);

 		if (ret)
 			return ret;
@@ -455,6 +459,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t fla
  * start_isolate_page_range() - mark page range MIGRATE_ISOLATE
  * @start_pfn:		The first PFN of the range to be isolated.
  * @end_pfn:		The last PFN of the range to be isolated.
+ * @mode:		isolation mode
  * @flags:		isolation flags
  *
  * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
@@ -488,7 +493,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t fla
  * Return: 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,
-			     isol_flags_t flags)
+			     isolate_mode_t mode, isolate_flags_t flags)
 {
 	unsigned long pfn;
 	struct page *page;
@@ -499,7 +504,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 	bool skip_isolation = false;

 	/* isolate [isolate_start, isolate_start + pageblock_nr_pages) pageblock */
-	ret = isolate_single_pageblock(isolate_start, flags, false,
+	ret = isolate_single_pageblock(isolate_start, mode, flags, false,
 			skip_isolation);
 	if (ret)
 		return ret;
@@ -508,7 +513,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 		skip_isolation = true;

 	/* isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock */
-	ret = isolate_single_pageblock(isolate_end, flags, true,
+	ret = isolate_single_pageblock(isolate_end, mode, flags, true,
 			skip_isolation);
 	if (ret) {
 		unset_migratetype_isolate(pfn_to_page(isolate_start));
@@ -520,7 +525,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 	     pfn < isolate_end - pageblock_nr_pages;
 	     pfn += pageblock_nr_pages) {
 		page = __first_valid_page(pfn, pageblock_nr_pages);
-		if (page && set_migratetype_isolate(page, flags,
+		if (page && set_migratetype_isolate(page, mode, flags,
 					start_pfn, end_pfn)) {
 			undo_isolate_page_range(isolate_start, pfn);
 			unset_migratetype_isolate(
@@ -563,7 +568,7 @@ void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
  */
 static unsigned long
 __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
-				  isol_flags_t flags)
+				  isolate_flags_t flags)
 {
 	struct page *page;

@@ -610,7 +615,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
  * Returns 0 if true, -EBUSY if one or more pages are in use.
  */
 int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
-			isol_flags_t isol_flags)
+			isolate_flags_t isol_flags)
 {
 	unsigned long pfn, flags;
 	struct page *page;
-- 
2.47.2



--
Best Regards,
Yan, Zi