mm: convert free_huge_page() to free_huge_folio()

Pass a folio instead of the head page to save a few instructions.  Update
the documentation, at least in English.

Link: https://lkml.kernel.org/r/20230816151201.3655946-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 24 insertions, 26 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5f498e8025cc..6a3c80026ab3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1706,10 +1706,10 @@ static void add_hugetlb_folio(struct hstate *h, struct folio *folio,
 	zeroed = folio_put_testzero(folio);
 	if (unlikely(!zeroed))
 		/*
-		 * It is VERY unlikely soneone else has taken a ref on
-		 * the page.  In this case, we simply return as the
-		 * hugetlb destructor (free_huge_page) will be called
-		 * when this other ref is dropped.
+		 * It is VERY unlikely soneone else has taken a ref
+		 * on the folio.  In this case, we simply return as
+		 * free_huge_folio() will be called when this other ref
+		 * is dropped.
 		 */
 		return;
 
@@ -1875,13 +1875,12 @@ struct hstate *size_to_hstate(unsigned long size)
 	return NULL;
 }
 
-void free_huge_page(struct page *page)
+void free_huge_folio(struct folio *folio)
 {
 	/*
 	 * Can't pass hstate in here because it is called from the
 	 * compound page destructor.
 	 */
-	struct folio *folio = page_folio(page);
 	struct hstate *h = folio_hstate(folio);
 	int nid = folio_nid(folio);
 	struct hugepage_subpool *spool = hugetlb_folio_subpool(folio);
@@ -1936,7 +1935,7 @@ void free_huge_page(struct page *page)
 		spin_unlock_irqrestore(&hugetlb_lock, flags);
 		update_and_free_hugetlb_folio(h, folio, true);
 	} else {
-		arch_clear_hugepage_flags(page);
+		arch_clear_hugepage_flags(&folio->page);
 		enqueue_hugetlb_folio(h, folio);
 		spin_unlock_irqrestore(&hugetlb_lock, flags);
 	}
@@ -2246,7 +2245,7 @@ static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
 		folio = alloc_fresh_hugetlb_folio(h, gfp_mask, node,
 					nodes_allowed, node_alloc_noretry);
 		if (folio) {
-			free_huge_page(&folio->page); /* free it into the hugepage allocator */
+			free_huge_folio(folio); /* free it into the hugepage allocator */
 			return 1;
 		}
 	}
@@ -2429,13 +2428,13 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h,
 	 * We could have raced with the pool size change.
 	 * Double check that and simply deallocate the new page
 	 * if we would end up overcommiting the surpluses. Abuse
-	 * temporary page to workaround the nasty free_huge_page
+	 * temporary page to workaround the nasty free_huge_folio
 	 * codeflow
 	 */
 	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
 		folio_set_hugetlb_temporary(folio);
 		spin_unlock_irq(&hugetlb_lock);
-		free_huge_page(&folio->page);
+		free_huge_folio(folio);
 		return NULL;
 	}
 
@@ -2547,8 +2546,7 @@ static int gather_surplus_pages(struct hstate *h, long delta)
 	__must_hold(&hugetlb_lock)
 {
 	LIST_HEAD(surplus_list);
-	struct folio *folio;
-	struct page *page, *tmp;
+	struct folio *folio, *tmp;
 	int ret;
 	long i;
 	long needed, allocated;
@@ -2608,21 +2606,21 @@ retry:
 	ret = 0;
 
 	/* Free the needed pages to the hugetlb pool */
-	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
+	list_for_each_entry_safe(folio, tmp, &surplus_list, lru) {
 		if ((--needed) < 0)
 			break;
 		/* Add the page to the hugetlb allocator */
-		enqueue_hugetlb_folio(h, page_folio(page));
+		enqueue_hugetlb_folio(h, folio);
 	}
 free:
 	spin_unlock_irq(&hugetlb_lock);
 
 	/*
 	 * Free unnecessary surplus pages to the buddy allocator.
-	 * Pages have no ref count, call free_huge_page directly.
+	 * Pages have no ref count, call free_huge_folio directly.
 	 */
-	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
-		free_huge_page(page);
+	list_for_each_entry_safe(folio, tmp, &surplus_list, lru)
+		free_huge_folio(folio);
 	spin_lock_irq(&hugetlb_lock);
 
 	return ret;
@@ -2836,11 +2834,11 @@ static long vma_del_reservation(struct hstate *h,
  * 2) No reservation was in place for the page, so hugetlb_restore_reserve is
  *    not set.  However, alloc_hugetlb_folio always updates the reserve map.
  *
- * In case 1, free_huge_page later in the error path will increment the
- * global reserve count.  But, free_huge_page does not have enough context
+ * In case 1, free_huge_folio later in the error path will increment the
+ * global reserve count.  But, free_huge_folio does not have enough context
  * to adjust the reservation map.  This case deals primarily with private
  * mappings.  Adjust the reserve map here to be consistent with global
- * reserve count adjustments to be made by free_huge_page.  Make sure the
+ * reserve count adjustments to be made by free_huge_folio.  Make sure the
  * reserve map indicates there is a reservation present.
  *
  * In case 2, simply undo reserve map modifications done by alloc_hugetlb_folio.
@@ -2856,7 +2854,7 @@ void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
 			 * Rare out of memory condition in reserve map
 			 * manipulation.  Clear hugetlb_restore_reserve so
 			 * that global reserve count will not be incremented
-			 * by free_huge_page.  This will make it appear
+			 * by free_huge_folio.  This will make it appear
 			 * as though the reservation for this folio was
 			 * consumed.  This may prevent the task from
 			 * faulting in the folio at a later time.  This
@@ -3232,7 +3230,7 @@ static void __init gather_bootmem_prealloc(void)
 		if (prep_compound_gigantic_folio(folio, huge_page_order(h))) {
 			WARN_ON(folio_test_reserved(folio));
 			prep_new_hugetlb_folio(h, folio, folio_nid(folio));
-			free_huge_page(page); /* add to the hugepage allocator */
+			free_huge_folio(folio); /* add to the hugepage allocator */
 		} else {
 			/* VERY unlikely inflated ref count on a tail page */
 			free_gigantic_folio(folio, huge_page_order(h));
@@ -3264,7 +3262,7 @@ static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
 					&node_states[N_MEMORY], NULL);
 			if (!folio)
 				break;
-			free_huge_page(&folio->page); /* free it into the hugepage allocator */
+			free_huge_folio(folio); /* free it into the hugepage allocator */
 		}
 		cond_resched();
 	}
@@ -3542,7 +3540,7 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
 	while (count > persistent_huge_pages(h)) {
 		/*
 		 * If this allocation races such that we no longer need the
-		 * page, free_huge_page will handle it by freeing the page
+		 * page, free_huge_folio will handle it by freeing the page
 		 * and reducing the surplus.
 		 */
 		spin_unlock_irq(&hugetlb_lock);
@@ -3658,7 +3656,7 @@ static int demote_free_hugetlb_folio(struct hstate *h, struct folio *folio)
 			prep_compound_page(subpage, target_hstate->order);
 		folio_change_private(inner_folio, NULL);
 		prep_new_hugetlb_folio(target_hstate, inner_folio, nid);
-		free_huge_page(subpage);
+		free_huge_folio(inner_folio);
 	}
 	mutex_unlock(&target_hstate->resize_lock);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 744848593360..30dc444436cc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -610,7 +610,7 @@ void destroy_large_folio(struct folio *folio)
 	enum compound_dtor_id dtor = folio->_folio_dtor;
 
 	if (folio_test_hugetlb(folio)) {
-		free_huge_page(&folio->page);
+		free_huge_folio(folio);
 		return;
 	}