[v5,4/6] docs/procfs: call out ioctl()-based PROCMAP_QUERY command existence

Commit Message

Andrii Nakryiko June 18, 2024, 10:45 p.m. UTC

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 <[e-mail]>
---
 Documentation/filesystems/proc.rst | 9 +++++++++
 1 file changed, 9 insertions(+)

Patch

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 82d142de3461..e834779d9611 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -443,6 +443,15 @@  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 and easy 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::