Re: [PATCH v5 1/6] mm: page_isolation: move has_unmovable_pages() to mm/page_isolation.c
On Fri, Feb 11, 2022 at 11:41:30AM -0500, Zi Yan wrote:
> From: Zi Yan
>
> has_unmovable_pages() is only used in mm/page_isolation.c. Move it from
> mm/page_alloc.c and make it static.
>
> Signed-off-by: Zi Yan
> Reviewed-by: Oscar Salvador
Reviewed-by: Mike Rapoport
> ---
> include/linux/page-isolation.h | 2 -
> mm/page_alloc.c| 119 -
> mm/page_isolation.c| 119 +
> 3 files changed, 119 insertions(+), 121 deletions(-)
>
> diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
> index 572458016331..e14eddf6741a 100644
> --- a/include/linux/page-isolation.h
> +++ b/include/linux/page-isolation.h
> @@ -33,8 +33,6 @@ 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);
> void set_pageblock_migratetype(struct page *page, int migratetype);
> int move_freepages_block(struct zone *zone, struct page *page,
> int migratetype, int *num_movable);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index cface1d38093..e2c6a67fc386 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -8962,125 +8962,6 @@ void *__init alloc_large_system_hash(const char
> *tablename,
> return table;
> }
>
> -/*
> - * This function checks whether pageblock includes unmovable pages or not.
> - *
> - * PageLRU check without isolation or lru_lock could race so that
> - * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
> - * check without lock_page also may miss some movable non-lru pages at
> - * race condition. So you can't expect this function should be exact.
> - *
> - * Returns a page without holding a reference. If the caller wants to
> - * dereference that page (e.g., dumping), it has to make sure that it
> - * cannot get removed (e.g., via memory unplug) concurrently.
> - *
> - */
> -struct page *has_unmovable_pages(struct zone *zone, struct page *page,
> - int migratetype, int flags)
> -{
> - unsigned long iter = 0;
> - unsigned long pfn = page_to_pfn(page);
> - unsigned long offset = pfn % pageblock_nr_pages;
> -
> - if (is_migrate_cma_page(page)) {
> - /*
> - * CMA allocations (alloc_contig_range) really need to mark
> - * isolate CMA pageblocks even when they are not movable in fact
> - * so consider them movable here.
> - */
> - if (is_migrate_cma(migratetype))
> - return NULL;
> -
> - return page;
> - }
> -
> - for (; iter < pageblock_nr_pages - offset; iter++) {
> - page = pfn_to_page(pfn + iter);
> -
> - /*
> - * Both, bootmem allocations and memory holes are marked
> - * PG_reserved and are unmovable. We can even have unmovable
> - * allocations inside ZONE_MOVABLE, for example when
> - * specifying "movablecore".
> - */
> - if (PageReserved(page))
> - return page;
> -
> - /*
> - * If the zone is movable and we have ruled out all reserved
> - * pages then it should be reasonably safe to assume the rest
> - * is movable.
> - */
> - if (zone_idx(zone) == ZONE_MOVABLE)
> - continue;
> -
> - /*
> - * Hugepages are not in LRU lists, but they're movable.
> - * THPs are on the LRU, but need to be counted as #small pages.
> - * We need not scan over tail pages because we don't
> - * handle each tail page individually in migration.
> - */
> - if (PageHuge(page) || PageTransCompound(page)) {
> - struct page *head = compound_head(page);
> - unsigned int skip_pages;
> -
> - if (PageHuge(page)) {
> - if
> (!hugepage_migration_supported(page_hstate(head)))
> - return page;
> - } else if (!PageLRU(head) && !__PageMovable(head)) {
> - return page;
> - }
> -
> - skip_pages = compound_nr(head) - (page - head);
> - iter += skip_pages - 1;
> - continue;
> - }
> -
> - /*
> - * We can't use page_count without pin a page
> - * because another CPU can free compound page.
> - * This check already skips compound tails of THP
> - * because their page->_refcount is zero at all time.
> - */
> - if (!page_ref_count(page)) {
> -
[PATCH v5 1/6] mm: page_isolation: move has_unmovable_pages() to mm/page_isolation.c
From: Zi Yan
has_unmovable_pages() is only used in mm/page_isolation.c. Move it from
mm/page_alloc.c and make it static.
Signed-off-by: Zi Yan
Reviewed-by: Oscar Salvador
---
include/linux/page-isolation.h | 2 -
mm/page_alloc.c| 119 -
mm/page_isolation.c| 119 +
3 files changed, 119 insertions(+), 121 deletions(-)
diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index 572458016331..e14eddf6741a 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -33,8 +33,6 @@ 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);
void set_pageblock_migratetype(struct page *page, int migratetype);
int move_freepages_block(struct zone *zone, struct page *page,
int migratetype, int *num_movable);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cface1d38093..e2c6a67fc386 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8962,125 +8962,6 @@ void *__init alloc_large_system_hash(const char
*tablename,
return table;
}
-/*
- * This function checks whether pageblock includes unmovable pages or not.
- *
- * PageLRU check without isolation or lru_lock could race so that
- * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
- * check without lock_page also may miss some movable non-lru pages at
- * race condition. So you can't expect this function should be exact.
- *
- * Returns a page without holding a reference. If the caller wants to
- * dereference that page (e.g., dumping), it has to make sure that it
- * cannot get removed (e.g., via memory unplug) concurrently.
- *
- */
-struct page *has_unmovable_pages(struct zone *zone, struct page *page,
-int migratetype, int flags)
-{
- unsigned long iter = 0;
- unsigned long pfn = page_to_pfn(page);
- unsigned long offset = pfn % pageblock_nr_pages;
-
- if (is_migrate_cma_page(page)) {
- /*
-* CMA allocations (alloc_contig_range) really need to mark
-* isolate CMA pageblocks even when they are not movable in fact
-* so consider them movable here.
-*/
- if (is_migrate_cma(migratetype))
- return NULL;
-
- return page;
- }
-
- for (; iter < pageblock_nr_pages - offset; iter++) {
- page = pfn_to_page(pfn + iter);
-
- /*
-* Both, bootmem allocations and memory holes are marked
-* PG_reserved and are unmovable. We can even have unmovable
-* allocations inside ZONE_MOVABLE, for example when
-* specifying "movablecore".
-*/
- if (PageReserved(page))
- return page;
-
- /*
-* If the zone is movable and we have ruled out all reserved
-* pages then it should be reasonably safe to assume the rest
-* is movable.
-*/
- if (zone_idx(zone) == ZONE_MOVABLE)
- continue;
-
- /*
-* Hugepages are not in LRU lists, but they're movable.
-* THPs are on the LRU, but need to be counted as #small pages.
-* We need not scan over tail pages because we don't
-* handle each tail page individually in migration.
-*/
- if (PageHuge(page) || PageTransCompound(page)) {
- struct page *head = compound_head(page);
- unsigned int skip_pages;
-
- if (PageHuge(page)) {
- if
(!hugepage_migration_supported(page_hstate(head)))
- return page;
- } else if (!PageLRU(head) && !__PageMovable(head)) {
- return page;
- }
-
- skip_pages = compound_nr(head) - (page - head);
- iter += skip_pages - 1;
- continue;
- }
-
- /*
-* We can't use page_count without pin a page
-* because another CPU can free compound page.
-* This check already skips compound tails of THP
-* because their page->_refcount is zero at all time.
-*/
- if (!page_ref_count(page)) {
- if (PageBuddy(page))
- iter += (1 << buddy_order(page)) - 1;
- continue;
- }
-
- /*
-* The HWPoisoned page may
