[RFC PATCH 4/7] mm: pageblock: allow set/unset migratetype for partial pageblock

Zi Yan
2021-05-06T15:26:20Z

From: Zi Yan <ziy@nvidia.com>

When we online subsections and pageblock size is larger than
a subsection, we should be able to change migratetype for partial
pageblocks. We also change the assumption that all pageblocks are in
a whole.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
include/linux/page-isolation.h | 8 ++++++--
mm/page_alloc.c | 27 ++++++++++++++++++---------
mm/page_isolation.c | 26 ++++++++++++++------------
3 files changed, 38 insertions(+), 23 deletions(-)

diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index 572458016331..308b540865b7 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -33,11 +33,15 @@ static inline bool is_migrate_isolate(int migratetype)
#define MEMORY_OFFLINE 0x1
#define REPORT_FAILURE 0x2

-struct page *has_unmovable_pages(struct zone *zone, struct page *page,
- int migratetype, int flags);
+struct page *has_unmovable_pages(struct zone *zone, unsigned long start_pfn,
+ unsigned long end_pfn, int migratetype,
+ int flags);
void set_pageblock_migratetype(struct page *page, int migratetype);
int move_freepages_block(struct zone *zone, struct page *page,
int migratetype, int *num_movable);
+int move_freepages(struct zone *zone,
+ unsigned long start_pfn, unsigned long end_pfn,
+ int migratetype, int *num_movable);

/*
* Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 72bb4a300e03..bc410f45c355 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2433,7 +2433,7 @@ static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
* Note that start_page and end_pages are not aligned on a pageblock
* boundary. If alignment is required, use move_freepages_block()
*/
-static int move_freepages(struct zone *zone,
+int move_freepages(struct zone *zone,
unsigned long start_pfn, unsigned long end_pfn,
int migratetype, int *num_movable)
{
@@ -6328,6 +6328,7 @@ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone
{
unsigned long pfn, end_pfn = start_pfn + size;
struct page *page;
+ bool set_migratetype = false;

if (highest_memmap_pfn < end_pfn - 1)
highest_memmap_pfn = end_pfn - 1;
@@ -6374,10 +6375,16 @@ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone
*/
if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
set_pageblock_migratetype(page, migratetype);
+ set_migratetype = true;
cond_resched();
}
pfn++;
}
+ /* in case the range is smaller than a pageblock */
+ if (!set_migratetype && context == MEMINIT_HOTPLUG) {
+ page = pfn_to_page(start_pfn);
+ set_pageblock_migratetype(page, migratetype);
+ }
}

#ifdef CONFIG_ZONE_DEVICE
@@ -8524,12 +8531,14 @@ void *__init alloc_large_system_hash(const char *tablename,
* cannot get removed (e.g., via memory unplug) concurrently.
*
*/
-struct page *has_unmovable_pages(struct zone *zone, struct page *page,
- int migratetype, int flags)
+struct page *has_unmovable_pages(struct zone *zone, unsigned long start_pfn,
+ unsigned long end_pfn, int migratetype,
+ int flags)
{
unsigned long iter = 0;
- unsigned long pfn = page_to_pfn(page);
- unsigned long offset = pfn % pageblock_nr_pages;
+ unsigned long pfn = start_pfn;
+ struct page *page = pfn_to_page(pfn);
+

if (is_migrate_cma_page(page)) {
/*
@@ -8543,11 +8552,11 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
return page;
}

- for (; iter < pageblock_nr_pages - offset; iter++) {
- if (!pfn_valid_within(pfn + iter))
+ for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+ if (!pfn_valid_within(pfn))
continue;

- page = pfn_to_page(pfn + iter);
+ page = pfn_to_page(pfn);

/*
* Both, bootmem allocations and memory holes are marked
@@ -8596,7 +8605,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
*/
if (!page_ref_count(page)) {
if (PageBuddy(page))
- iter += (1 << buddy_order(page)) - 1;
+ pfn += (1 << buddy_order(page)) - 1;
continue;
}

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index bddf788f45bf..c1b9b8848382 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -15,8 +15,10 @@
#define CREATE_TRACE_POINTS
#include <trace/events/page_isolation.h>

-static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags)
+static int set_migratetype_isolate(unsigned long start_pfn, unsigned long end_pfn,
+ int migratetype, int isol_flags)
{
+ struct page *page = pfn_to_page(start_pfn);
struct zone *zone = page_zone(page);
struct page *unmovable;
unsigned long flags;
@@ -37,15 +39,14 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
* FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
* We just check MOVABLE pages.
*/
- unmovable = has_unmovable_pages(zone, page, migratetype, isol_flags);
+ unmovable = has_unmovable_pages(zone, start_pfn, end_pfn, migratetype, isol_flags);
if (!unmovable) {
unsigned long nr_pages;
int mt = get_pageblock_migratetype(page);

set_pageblock_migratetype(page, MIGRATE_ISOLATE);
zone->nr_isolate_pageblock++;
- nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE,
- NULL);
+ nr_pages = move_freepages(zone, start_pfn, end_pfn, MIGRATE_ISOLATE, NULL);

__mod_zone_freepage_state(zone, -nr_pages, mt);
spin_unlock_irqrestore(&zone->lock, flags);
@@ -64,7 +65,8 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
return -EBUSY;
}

-static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
+static void unset_migratetype_isolate(unsigned long start_pfn, unsigned long end_pfn,
+ unsigned migratetype)
{
struct zone *zone;
unsigned long flags, nr_pages;
@@ -72,6 +74,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
unsigned int order;
unsigned long pfn, buddy_pfn;
struct page *buddy;
+ struct page *page = pfn_to_page(start_pfn);

zone = page_zone(page);
spin_lock_irqsave(&zone->lock, flags);
@@ -112,7 +115,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
* allocation.
*/
if (!isolated_page) {
- nr_pages = move_freepages_block(zone, page, migratetype, NULL);
+ nr_pages = move_freepages(zone, start_pfn, end_pfn, migratetype, NULL);
__mod_zone_freepage_state(zone, nr_pages, migratetype);
}
set_pageblock_migratetype(page, migratetype);
@@ -195,7 +198,8 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (page) {
- if (set_migratetype_isolate(page, migratetype, flags)) {
+ if (set_migratetype_isolate(pfn, min(end_pfn, pfn + pageblock_nr_pages),
+ migratetype, flags)) {
undo_pfn = pfn;
goto undo;
}
@@ -209,7 +213,8 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
struct page *page = pfn_to_online_page(pfn);
if (!page)
continue;
- unset_migratetype_isolate(page, migratetype);
+ unset_migratetype_isolate(pfn, min(pfn + pageblock_nr_pages, undo_pfn),
+ migratetype);
}

return -EBUSY;
@@ -224,16 +229,13 @@ void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned long pfn;
struct page *page;

- BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
- BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
-
for (pfn = start_pfn;
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (!page || !is_migrate_isolate_page(page))
continue;
- unset_migratetype_isolate(page, migratetype);
+ unset_migratetype_isolate(pfn, min(pfn + pageblock_nr_pages, end_pfn), migratetype);
}
}
/*
--
2.30.2