1 files changed, 44 insertions, 18 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 615b5d323ee2..5cb970d51f0a 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -76,7 +76,9 @@
 
 #include <asm/tlbflush.h>
 
+#define CREATE_TRACE_POINTS
 #include <trace/events/tlb.h>
+#include <trace/events/migrate.h>
 
 #include "internal.h"
 
@@ -1236,14 +1238,14 @@ void page_add_new_anon_rmap(struct page *page,
 void page_add_file_rmap(struct page *page,
 	struct vm_area_struct *vma, bool compound)
 {
-	int i, nr = 1;
+	int i, nr = 0;
 
 	VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
 	lock_page_memcg(page);
 	if (compound && PageTransHuge(page)) {
 		int nr_pages = thp_nr_pages(page);
 
-		for (i = 0, nr = 0; i < nr_pages; i++) {
+		for (i = 0; i < nr_pages; i++) {
 			if (atomic_inc_and_test(&page[i]._mapcount))
 				nr++;
 		}
@@ -1271,11 +1273,12 @@ void page_add_file_rmap(struct page *page,
 			VM_WARN_ON_ONCE(!PageLocked(page));
 			SetPageDoubleMap(compound_head(page));
 		}
-		if (!atomic_inc_and_test(&page->_mapcount))
-			goto out;
+		if (atomic_inc_and_test(&page->_mapcount))
+			nr++;
 	}
-	__mod_lruvec_page_state(page, NR_FILE_MAPPED, nr);
 out:
+	if (nr)
+		__mod_lruvec_page_state(page, NR_FILE_MAPPED, nr);
 	unlock_page_memcg(page);
 
 	mlock_vma_page(page, vma, compound);
@@ -1283,7 +1286,7 @@ out:
 
 static void page_remove_file_rmap(struct page *page, bool compound)
 {
-	int i, nr = 1;
+	int i, nr = 0;
 
 	VM_BUG_ON_PAGE(compound && !PageHead(page), page);
 
@@ -1298,12 +1301,12 @@ static void page_remove_file_rmap(struct page *page, bool compound)
 	if (compound && PageTransHuge(page)) {
 		int nr_pages = thp_nr_pages(page);
 
-		for (i = 0, nr = 0; i < nr_pages; i++) {
+		for (i = 0; i < nr_pages; i++) {
 			if (atomic_add_negative(-1, &page[i]._mapcount))
 				nr++;
 		}
 		if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
-			return;
+			goto out;
 		if (PageSwapBacked(page))
 			__mod_lruvec_page_state(page, NR_SHMEM_PMDMAPPED,
 						-nr_pages);
@@ -1311,16 +1314,12 @@ static void page_remove_file_rmap(struct page *page, bool compound)
 			__mod_lruvec_page_state(page, NR_FILE_PMDMAPPED,
 						-nr_pages);
 	} else {
-		if (!atomic_add_negative(-1, &page->_mapcount))
-			return;
+		if (atomic_add_negative(-1, &page->_mapcount))
+			nr++;
 	}
-
-	/*
-	 * We use the irq-unsafe __{inc|mod}_lruvec_page_state because
-	 * these counters are not modified in interrupt context, and
-	 * pte lock(a spinlock) is held, which implies preemption disabled.
-	 */
-	__mod_lruvec_page_state(page, NR_FILE_MAPPED, -nr);
+out:
+	if (nr)
+		__mod_lruvec_page_state(page, NR_FILE_MAPPED, -nr);
 }
 
 static void page_remove_anon_compound_rmap(struct page *page)
@@ -1589,7 +1588,30 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 
 			/* MADV_FREE page check */
 			if (!folio_test_swapbacked(folio)) {
-				if (!folio_test_dirty(folio)) {
+				int ref_count, map_count;
+
+				/*
+				 * Synchronize with gup_pte_range():
+				 * - clear PTE; barrier; read refcount
+				 * - inc refcount; barrier; read PTE
+				 */
+				smp_mb();
+
+				ref_count = folio_ref_count(folio);
+				map_count = folio_mapcount(folio);
+
+				/*
+				 * Order reads for page refcount and dirty flag
+				 * (see comments in __remove_mapping()).
+				 */
+				smp_rmb();
+
+				/*
+				 * The only page refs must be one from isolation
+				 * plus the rmap(s) (dropped by discard:).
+				 */
+				if (ref_count == 1 + map_count &&
+				    !folio_test_dirty(folio)) {
 					/* Invalidate as we cleared the pte */
 					mmu_notifier_invalidate_range(mm,
 						address, address + PAGE_SIZE);
@@ -1852,6 +1874,8 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
 			if (pte_swp_uffd_wp(pteval))
 				swp_pte = pte_swp_mkuffd_wp(swp_pte);
 			set_pte_at(mm, pvmw.address, pvmw.pte, swp_pte);
+			trace_set_migration_pte(pvmw.address, pte_val(swp_pte),
+						compound_order(&folio->page));
 			/*
 			 * No need to invalidate here it will synchronize on
 			 * against the special swap migration pte.
@@ -1920,6 +1944,8 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
 			if (pte_uffd_wp(pteval))
 				swp_pte = pte_swp_mkuffd_wp(swp_pte);
 			set_pte_at(mm, address, pvmw.pte, swp_pte);
+			trace_set_migration_pte(address, pte_val(swp_pte),
+						compound_order(&folio->page));
 			/*
 			 * No need to invalidate here it will synchronize on
 			 * against the special swap migration pte.