mm: mempolicy: make mpol_misplaced() to take a folio

In preparation for large folio numa balancing, make mpol_misplaced() to
take a folio, no functional change intended.

Link: https://lkml.kernel.org/r/20230921074417.24004-6-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mempolicy.h

@@ -174,7 +174,7 @@ extern void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol);
 /* Check if a vma is migratable */
 extern bool vma_migratable(struct vm_area_struct *vma);
 
-extern int mpol_misplaced(struct page *, struct vm_area_struct *, unsigned long);
+int mpol_misplaced(struct folio *, struct vm_area_struct *, unsigned long);
 extern void mpol_put_task_policy(struct task_struct *);
 
 static inline bool mpol_is_preferred_many(struct mempolicy *pol)
@@ -278,7 +278,8 @@ static inline int mpol_parse_str(char *str, struct mempolicy **mpol)
 }
 #endif
 
-static inline int mpol_misplaced(struct page *page, struct vm_area_struct *vma,
+static inline int mpol_misplaced(struct folio *folio,
+				 struct vm_area_struct *vma,
 				 unsigned long address)
 {
 	return -1; /* no node preference */

mm/memory.c

@@ -4738,7 +4738,7 @@ int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma,
 		*flags |= TNF_FAULT_LOCAL;
 	}
 
-	return mpol_misplaced(&folio->page, vma, addr);
+	return mpol_misplaced(folio, vma, addr);
 }
 
 static vm_fault_t do_numa_page(struct vm_fault *vmf)

mm/mempolicy.c

@@ -2564,24 +2564,25 @@ static void sp_free(struct sp_node *n)
 }
 
 /**
- * mpol_misplaced - check whether current page node is valid in policy
+ * mpol_misplaced - check whether current folio node is valid in policy
  *
- * @page: page to be checked
- * @vma: vm area where page mapped
- * @addr: virtual address where page mapped
+ * @folio: folio to be checked
+ * @vma: vm area where folio mapped
+ * @addr: virtual address in @vma for shared policy lookup and interleave policy
  *
- * Lookup current policy node id for vma,addr and "compare to" page's
+ * Lookup current policy node id for vma,addr and "compare to" folio's
  * node id.  Policy determination "mimics" alloc_page_vma().
  * Called from fault path where we know the vma and faulting address.
  *
  * Return: NUMA_NO_NODE if the page is in a node that is valid for this
- * policy, or a suitable node ID to allocate a replacement page from.
+ * policy, or a suitable node ID to allocate a replacement folio from.
  */
-int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
+int mpol_misplaced(struct folio *folio, struct vm_area_struct *vma,
+		   unsigned long addr)
 {
 	struct mempolicy *pol;
 	struct zoneref *z;
-	int curnid = page_to_nid(page);
+	int curnid = folio_nid(folio);
 	unsigned long pgoff;
 	int thiscpu = raw_smp_processor_id();
 	int thisnid = cpu_to_node(thiscpu);
@@ -2637,11 +2638,12 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
 		BUG();
 	}
 
-	/* Migrate the page towards the node whose CPU is referencing it */
+	/* Migrate the folio towards the node whose CPU is referencing it */
 	if (pol->flags & MPOL_F_MORON) {
 		polnid = thisnid;
 
-		if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
+		if (!should_numa_migrate_memory(current, &folio->page, curnid,
+						thiscpu))
 			goto out;
 	}