1 files changed, 51 insertions, 0 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 187b3b5f242e..85ef60fdf2c0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -451,6 +451,7 @@ struct mem_size_stats {
 	unsigned long private_hugetlb;
 	u64 pss;
 	u64 swap_pss;
+	bool check_shmem_swap;
 };
 
 static void smaps_account(struct mem_size_stats *mss, struct page *page,
@@ -485,6 +486,45 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page,
 	}
 }
 
+#ifdef CONFIG_SHMEM
+static unsigned long smaps_shmem_swap(struct vm_area_struct *vma,
+		unsigned long addr)
+{
+	struct page *page;
+
+	page = find_get_entry(vma->vm_file->f_mapping,
+					linear_page_index(vma, addr));
+	if (!page)
+		return 0;
+
+	if (radix_tree_exceptional_entry(page))
+		return PAGE_SIZE;
+
+	page_cache_release(page);
+	return 0;
+
+}
+
+static int smaps_pte_hole(unsigned long addr, unsigned long end,
+		struct mm_walk *walk)
+{
+	struct mem_size_stats *mss = walk->private;
+
+	while (addr < end) {
+		mss->swap += smaps_shmem_swap(walk->vma, addr);
+		addr += PAGE_SIZE;
+	}
+
+	return 0;
+}
+#else
+static unsigned long smaps_shmem_swap(struct vm_area_struct *vma,
+		unsigned long addr)
+{
+	return 0;
+}
+#endif
+
 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 		struct mm_walk *walk)
 {
@@ -512,6 +552,9 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 			}
 		} else if (is_migration_entry(swpent))
 			page = migration_entry_to_page(swpent);
+	} else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap
+							&& pte_none(*pte))) {
+		mss->swap += smaps_shmem_swap(vma, addr);
 	}
 
 	if (!page)
@@ -671,6 +714,14 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 	};
 
 	memset(&mss, 0, sizeof mss);
+
+#ifdef CONFIG_SHMEM
+	if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
+		mss.check_shmem_swap = true;
+		smaps_walk.pte_hole = smaps_pte_hole;
+	}
+#endif
+
 	/* mmap_sem is held in m_start */
 	walk_page_vma(vma, &smaps_walk);