[PATCH v7 4/6] mm/page_isolation: remove migratetype from move_freepages_block_isolate()

From: Zi Yan
Date: Mon Jun 02 2025 - 11:24:45 EST

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Since migratetype is no longer overwritten during pageblock isolation,
moving a pageblock out of MIGRATE_ISOLATE no longer needs a new
migratetype.

Add pageblock_isolate_and_move_free_pages() and
pageblock_unisolate_and_move_free_pages() to be explicit about the page
isolation operations. Both share the common code in
__move_freepages_block_isolate(), which is renamed from
move_freepages_block_isolate().

Add toggle_pageblock_isolate() to flip pageblock isolation bit in
__move_freepages_block_isolate().

Make set_pageblock_migratetype() only accept non MIGRATE_ISOLATE types,
so that one should use set_pageblock_isolate() to isolate pageblocks.
As a result, move pageblock migratetype code out of
__move_freepages_block().

Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
---
include/linux/page-isolation.h | 5 +--
mm/page_alloc.c | 80 ++++++++++++++++++++++++++--------
mm/page_isolation.c | 21 +++++----
3 files changed, 75 insertions(+), 31 deletions(-)

diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index 14c6a5f691c2..7241a6719618 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -44,10 +44,9 @@ static inline void set_pageblock_isolate(struct page *page)
void __meminit init_pageblock_migratetype(struct page *page,
enum migratetype migratetype,
bool isolate);
-void set_pageblock_migratetype(struct page *page, enum migratetype migratetype);

-bool move_freepages_block_isolate(struct zone *zone, struct page *page,
- int migratetype);
+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,
int migratetype, int flags);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 92a368d38d77..6ddf4fd6b2bd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -525,8 +525,8 @@ void clear_pfnblock_bit(const struct page *page, unsigned long pfn,
* @page: The page within the block of interest
* @migratetype: migratetype to set
*/
-__always_inline void set_pageblock_migratetype(struct page *page,
- enum migratetype migratetype)
+static void set_pageblock_migratetype(struct page *page,
+ enum migratetype migratetype)
{
if (unlikely(page_group_by_mobility_disabled &&
migratetype < MIGRATE_PCPTYPES))
@@ -534,9 +534,13 @@ __always_inline void set_pageblock_migratetype(struct page *page,

#ifdef CONFIG_MEMORY_ISOLATION
if (migratetype == MIGRATE_ISOLATE) {
- set_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate);
+ VM_WARN_ONCE(1,
+ "Use set_pageblock_isolate() for pageblock isolation");
return;
}
+ VM_WARN_ONCE(get_pfnblock_bit(page, page_to_pfn(page),
+ PB_migrate_isolate),
+ "Use clear_pageblock_isolate() to unisolate pageblock");
/* MIGRATETYPE_AND_ISO_MASK clears PB_migrate_isolate if it is set */
#endif
__set_pfnblock_flags_mask(page, page_to_pfn(page),
@@ -1923,8 +1927,8 @@ static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
#endif

/*
- * Change the type of a block and move all its free pages to that
- * type's freelist.
+ * Move all free pages of a block to new type's freelist. Caller needs to
+ * change the block type.
*/
static int __move_freepages_block(struct zone *zone, unsigned long start_pfn,
int old_mt, int new_mt)
@@ -1956,8 +1960,6 @@ static int __move_freepages_block(struct zone *zone, unsigned long start_pfn,
pages_moved += 1 << order;
}

- set_pageblock_migratetype(pfn_to_page(start_pfn), new_mt);
-
return pages_moved;
}

@@ -2015,11 +2017,16 @@ static int move_freepages_block(struct zone *zone, struct page *page,
int old_mt, int new_mt)
{
unsigned long start_pfn;
+ int res;

if (!prep_move_freepages_block(zone, page, &start_pfn, NULL, NULL))
return -1;

- return __move_freepages_block(zone, start_pfn, old_mt, new_mt);
+ res = __move_freepages_block(zone, start_pfn, old_mt, new_mt);
+ set_pageblock_migratetype(pfn_to_page(start_pfn), new_mt);
+
+ return res;
+
}

#ifdef CONFIG_MEMORY_ISOLATION
@@ -2047,11 +2054,19 @@ static unsigned long find_large_buddy(unsigned long start_pfn)
return start_pfn;
}

+static inline void toggle_pageblock_isolate(struct page *page, bool isolate)
+{
+ if (isolate)
+ set_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate);
+ else
+ clear_pfnblock_bit(page, page_to_pfn(page), PB_migrate_isolate);
+}
+
/**
- * move_freepages_block_isolate - move free pages in block for page isolation
+ * __move_freepages_block_isolate - move free pages in block for page isolation
* @zone: the zone
* @page: the pageblock page
- * @migratetype: migratetype to set on the pageblock
+ * @isolate: to isolate the given pageblock or unisolate it
*
* This is similar to move_freepages_block(), but handles the special
* case encountered in page isolation, where the block of interest
@@ -2066,10 +2081,18 @@ static unsigned long find_large_buddy(unsigned long start_pfn)
*
* Returns %true if pages could be moved, %false otherwise.
*/
-bool move_freepages_block_isolate(struct zone *zone, struct page *page,
- int migratetype)
+static bool __move_freepages_block_isolate(struct zone *zone,
+ struct page *page, bool isolate)
{
unsigned long start_pfn, pfn;
+ int from_mt;
+ int to_mt;
+
+ if (isolate == get_pageblock_isolate(page)) {
+ VM_WARN_ONCE(1, "%s a pageblock that is already in that state",
+ isolate ? "Isolate" : "Unisolate");
+ return false;
+ }

if (!prep_move_freepages_block(zone, page, &start_pfn, NULL, NULL))
return false;
@@ -2086,7 +2109,7 @@ bool move_freepages_block_isolate(struct zone *zone, struct page *page,

del_page_from_free_list(buddy, zone, order,
get_pfnblock_migratetype(buddy, pfn));
- set_pageblock_migratetype(page, migratetype);
+ toggle_pageblock_isolate(page, isolate);
split_large_buddy(zone, buddy, pfn, order, FPI_NONE);
return true;
}
@@ -2097,16 +2120,38 @@ bool move_freepages_block_isolate(struct zone *zone, struct page *page,

del_page_from_free_list(page, zone, order,
get_pfnblock_migratetype(page, pfn));
- set_pageblock_migratetype(page, migratetype);
+ toggle_pageblock_isolate(page, isolate);
split_large_buddy(zone, page, pfn, order, FPI_NONE);
return true;
}
move:
- __move_freepages_block(zone, start_pfn,
- get_pfnblock_migratetype(page, start_pfn),
- migratetype);
+ /* Use MIGRATETYPE_MASK to get non-isolate migratetype */
+ if (isolate) {
+ from_mt = __get_pfnblock_flags_mask(page, page_to_pfn(page),
+ MIGRATETYPE_MASK);
+ to_mt = MIGRATE_ISOLATE;
+ } else {
+ from_mt = MIGRATE_ISOLATE;
+ to_mt = __get_pfnblock_flags_mask(page, page_to_pfn(page),
+ MIGRATETYPE_MASK);
+ }
+
+ __move_freepages_block(zone, start_pfn, from_mt, to_mt);
+ toggle_pageblock_isolate(pfn_to_page(start_pfn), isolate);
+
return true;
}
+
+bool pageblock_isolate_and_move_free_pages(struct zone *zone, struct page *page)
+{
+ return __move_freepages_block_isolate(zone, page, true);
+}
+
+bool pageblock_unisolate_and_move_free_pages(struct zone *zone, struct page *page)
+{
+ return __move_freepages_block_isolate(zone, page, false);
+}
+
#endif /* CONFIG_MEMORY_ISOLATION */

static void change_pageblock_range(struct page *pageblock_page,
@@ -2298,6 +2343,7 @@ try_to_claim_block(struct zone *zone, struct page *page,
if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
page_group_by_mobility_disabled) {
__move_freepages_block(zone, start_pfn, block_type, start_type);
+ set_pageblock_migratetype(pfn_to_page(start_pfn), start_type);
return __rmqueue_smallest(zone, order, start_type);
}

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index b2fc5266e3d2..08f627a5032f 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -188,7 +188,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
migratetype, isol_flags);
if (!unmovable) {
- if (!move_freepages_block_isolate(zone, page, MIGRATE_ISOLATE)) {
+ if (!pageblock_isolate_and_move_free_pages(zone, page)) {
spin_unlock_irqrestore(&zone->lock, flags);
return -EBUSY;
}
@@ -209,7 +209,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
return -EBUSY;
}

-static void unset_migratetype_isolate(struct page *page, int migratetype)
+static void unset_migratetype_isolate(struct page *page)
{
struct zone *zone;
unsigned long flags;
@@ -262,10 +262,10 @@ static void unset_migratetype_isolate(struct page *page, int migratetype)
* Isolating this block already succeeded, so this
* should not fail on zone boundaries.
*/
- WARN_ON_ONCE(!move_freepages_block_isolate(zone, page, migratetype));
+ WARN_ON_ONCE(!pageblock_unisolate_and_move_free_pages(zone, page));
} else {
- set_pageblock_migratetype(page, migratetype);
- __putback_isolated_page(page, order, migratetype);
+ clear_pageblock_isolate(page);
+ __putback_isolated_page(page, order, get_pageblock_migratetype(page));
}
zone->nr_isolate_pageblock--;
out:
@@ -383,7 +383,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
if (PageBuddy(page)) {
int order = buddy_order(page);

- /* move_freepages_block_isolate() handled this */
+ /* pageblock_isolate_and_move_free_pages() handled this */
VM_WARN_ON_ONCE(pfn + (1 << order) > boundary_pfn);

pfn += 1UL << order;
@@ -433,7 +433,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
failed:
/* restore the original migratetype */
if (!skip_isolation)
- unset_migratetype_isolate(pfn_to_page(isolate_pageblock), migratetype);
+ unset_migratetype_isolate(pfn_to_page(isolate_pageblock));
return -EBUSY;
}

@@ -504,7 +504,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
ret = isolate_single_pageblock(isolate_end, flags, true,
skip_isolation, migratetype);
if (ret) {
- unset_migratetype_isolate(pfn_to_page(isolate_start), migratetype);
+ unset_migratetype_isolate(pfn_to_page(isolate_start));
return ret;
}

@@ -517,8 +517,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
start_pfn, end_pfn)) {
undo_isolate_page_range(isolate_start, pfn, migratetype);
unset_migratetype_isolate(
- pfn_to_page(isolate_end - pageblock_nr_pages),
- migratetype);
+ pfn_to_page(isolate_end - pageblock_nr_pages));
return -EBUSY;
}
}
@@ -548,7 +547,7 @@ void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
page = __first_valid_page(pfn, pageblock_nr_pages);
if (!page || !is_migrate_isolate_page(page))
continue;
- unset_migratetype_isolate(page, migratetype);
+ unset_migratetype_isolate(page);
}
}
/*
--
2.47.2

Next message: Zi Yan: "[PATCH v7 6/6] mm/page_isolation: remove migratetype parameter from more functions."
Previous message: Matthew Wilcox: "Re: [GIT PULL] Additional MM updates for 6.16-rc1"
In reply to: Zi Yan: "[PATCH v7 0/6] Make MIGRATE_ISOLATE a standalone bit"
Next in thread: Zi Yan: "[PATCH v7 6/6] mm/page_isolation: remove migratetype parameter from more functions."
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]