Call out PROCMAP_QUERY ioctl() existence in the section describing
/proc/PID/maps file in documentation. We refer user to UAPI header for
low-level details of this programmatic interface.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 Documentation/filesystems/proc.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 7c3a565ffbef..f2bbd1e86204 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -443,6 +443,14 @@ is not associated with a file:
 
  or if empty, the mapping is anonymous.
 
+Starting with 6.11 kernel, /proc/PID/maps provides an alternative
+ioctl()-based API that gives ability to flexibly and efficiently query and
+filter individual VMAs.  This interface is binary and is meant for more
+efficient programmatic use. `struct procmap_query`, defined in linux/fs.h UAPI
+header, serves as an input/output argument to the `PROCMAP_QUERY` ioctl()
+command. See comments in linus/fs.h UAPI header for details on query
+semantics, supported flags, data returned, and general API usage information.
+
 The /proc/PID/smaps is an extension based on maps, showing the memory
 consumption for each of the process's mappings. For each mapping (aka Virtual
 Memory Area, or VMA) there is a series of lines such as the following::
-- 
2.43.0