[PATCH v6 2/5] drm/pagemap: Unlock and put folios when possible

[Francois Dugast <francois.dugast@intel.com>]

If the page is part of a folio, unlock and put the whole folio at once
instead of individual pages one after the other. This will reduce the
amount of operations once device THP are in use.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: linux-mm@kvack.org
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
---
 drivers/gpu/drm/drm_pagemap.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
index 38eca94f01a1..8e24a2c24729 100644
--- a/drivers/gpu/drm/drm_pagemap.c
+++ b/drivers/gpu/drm/drm_pagemap.c
@@ -154,15 +154,15 @@ static void drm_pagemap_zdd_put(struct drm_pagemap_zdd *zdd)
 }
 
 /**
- * drm_pagemap_migration_unlock_put_page() - Put a migration page
- * @page: Pointer to the page to put
+ * drm_pagemap_migration_unlock_put_folio() - Put a migration folio
+ * @folio: Pointer to the folio to put
  *
- * This function unlocks and puts a page.
+ * This function unlocks and puts a folio.
  */
-static void drm_pagemap_migration_unlock_put_page(struct page *page)
+static void drm_pagemap_migration_unlock_put_folio(struct folio *folio)
 {
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 }
 
 /**
@@ -177,15 +177,23 @@ static void drm_pagemap_migration_unlock_put_pages(unsigned long npages,
 {
 	unsigned long i;
 
-	for (i = 0; i < npages; ++i) {
+	for (i = 0; i < npages;) {
 		struct page *page;
+		struct folio *folio;
+		unsigned int order = 0;
 
 		if (!migrate_pfn[i])
-			continue;
+			goto next;
 
 		page = migrate_pfn_to_page(migrate_pfn[i]);
-		drm_pagemap_migration_unlock_put_page(page);
+		folio = page_folio(page);
+		order = folio_order(folio);
+
+		drm_pagemap_migration_unlock_put_folio(folio);
 		migrate_pfn[i] = 0;
+
+next:
+		i += NR_PAGES(order);
 	}
 }
 
-- 
2.43.0