diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index ca8213d7e53e..d98bbd7cd38f 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1274,23 +1274,18 @@ static void smap_gather_stats(struct proc_maps_private *priv, if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) { /* - * For shared or readonly shmem mappings we know that all - * swapped out pages belong to the shmem object, and we can - * obtain the swap value much more efficiently. For private - * writable mappings, we might have COW pages that are - * not affected by the parent swapped out pages of the shmem - * object, so we have to distinguish them during the page walk. - * Unless we know that the shmem object (or the part mapped by - * our VMA) has no swapped out pages at all. + * CoW mappings might map anon folios that do not belong to + * shmem. Perform a less efficient page table walk in this + * situation, unless we know that the shmem object (or the + * part mapped by our VMA) has no swapped out pages at all. */ - unsigned long shmem_swapped = shmem_swap_usage(vma); + const unsigned long shmem_swapped = shmem_swap_usage(vma); + const bool is_cow = vma_is_cow_mapping(vma); - if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) || - !(vma->vm_flags & VM_WRITE))) { - mss->swap += shmem_swapped; - } else { + if (start || (shmem_swapped && is_cow)) ops = get_smaps_shmem_walk_ops(priv); - } + else + mss->swap += shmem_swapped; } if (!start)