diff --git a/Documentation/ABI/testing/procfs-smaps_rollup b/Documentation/ABI/testing/procfs-smaps_rollup
index a4e31c465194..b446a7154a1b 100644
--- a/Documentation/ABI/testing/procfs-smaps_rollup
+++ b/Documentation/ABI/testing/procfs-smaps_rollup
@@ -22,6 +22,7 @@ Description:
 			MMUPageSize:           4 kB
 			Rss:		     884 kB
 			Pss:		     385 kB
+			Pss_Dirty:	      68 kB
 			Pss_Anon:	     301 kB
 			Pss_File:	      80 kB
 			Pss_Shmem:	       4 kB
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 8543a59f288f..0b5120ff506c 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -448,6 +448,7 @@ Memory Area, or VMA) there is a series of lines such as the following::
     MMUPageSize:           4 kB
     Rss:                 892 kB
     Pss:                 374 kB
+    Pss_Dirty:             0 kB
     Shared_Clean:        892 kB
     Shared_Dirty:          0 kB
     Private_Clean:         0 kB
@@ -479,7 +480,9 @@ dirty shared and private pages in the mapping.
 The "proportional set size" (PSS) of a process is the count of pages it has
 in memory, where each page is divided by the number of processes sharing it.
 So if a process has 1000 pages all to itself, and 1000 shared with one other
-process, its PSS will be 1500.
+process, its PSS will be 1500.  "Pss_Dirty" is the portion of PSS which
+consists of dirty pages.  ("Pss_Clean" is not included, but it can be
+calculated by subtracting "Pss_Dirty" from "Pss".)
 
 Note that even a page which is part of a MAP_SHARED mapping, but has only
 a single pte mapped, i.e.  is currently used by only one process, is accounted
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2d04e3470d4c..751c19d5bfdd 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -406,6 +406,7 @@ struct mem_size_stats {
 	u64 pss_anon;
 	u64 pss_file;
 	u64 pss_shmem;
+	u64 pss_dirty;
 	u64 pss_locked;
 	u64 swap_pss;
 };
@@ -427,6 +428,7 @@ static void smaps_page_accumulate(struct mem_size_stats *mss,
 		mss->pss_locked += pss;
 
 	if (dirty || PageDirty(page)) {
+		mss->pss_dirty += pss;
 		if (private)
 			mss->private_dirty += size;
 		else
@@ -808,6 +810,7 @@ static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
 {
 	SEQ_PUT_DEC("Rss:            ", mss->resident);
 	SEQ_PUT_DEC(" kB\nPss:            ", mss->pss >> PSS_SHIFT);
+	SEQ_PUT_DEC(" kB\nPss_Dirty:      ", mss->pss_dirty >> PSS_SHIFT);
 	if (rollup_mode) {
 		/*
 		 * These are meaningful only for smaps_rollup, otherwise two of