[PATCH RFC v2 4/4] mm/ksm: add force merging/unmerging documentation

[Oleksandr Natalenko <oleksandr@redhat.com>]

Document respective sysfs knob.

Signed-off-by: Oleksandr Natalenko <oleksandr@redhat.com>
---
 Documentation/admin-guide/mm/ksm.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
index 9303786632d1..4302b92910ec 100644
--- a/Documentation/admin-guide/mm/ksm.rst
+++ b/Documentation/admin-guide/mm/ksm.rst
@@ -78,6 +78,17 @@ KSM daemon sysfs interface
 The KSM daemon is controlled by sysfs files in ``/sys/kernel/mm/ksm/``,
 readable by all but writable only by root:
 
+force_madvise
+        write-only control to force merging/unmerging for specific
+        task.
+
+        To mark the VMAs as mergeable, use:
+        ``echo PID > /sys/kernel/mm/ksm/force_madvise``
+
+        To unmerge all the VMAs, use:
+        ``echo -PID > /sys/kernel/mm/ksm/force_madvise``
+        (note the prepending "minus")
+
 pages_to_scan
         how many pages to scan before ksmd goes to sleep
         e.g. ``echo 100 > /sys/kernel/mm/ksm/pages_to_scan``.
-- 
2.21.0