UFFD_FEATURE_THREAD_ID is supported since Linux 4.14.
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
man2/userfaultfd.2 | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
index e7dc9f813..2d14effc6 100644
--- a/man2/userfaultfd.2
+++ b/man2/userfaultfd.2
@@ -77,6 +77,12 @@ When the last file descriptor referring to a userfaultfd object is closed,
all memory ranges that were registered with the object are unregistered
and unread events are flushed.
.\"
+.PP
+Since Linux 4.14, userfaultfd page fault message can selectively embed fault
+thread ID information into the fault message. One needs to enable this feature
+explicitly using the
+.BR UFFD_FEATURE_THREAD_ID