fs, proc: introduce /proc/<pid>/task/<tid>/children entry

[platform/adaptation/renesas_rcar/renesas_kernel.git] / Documentation / filesystems / proc.txt

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 912af6c..d8d3f9a 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -40,6 +40,7 @@ Table of Contents
   3.4  /proc/<pid>/coredump_filter - Core dump filtering settings
   3.5  /proc/<pid>/mountinfo - Information about mounts
   3.6  /proc/<pid>/comm  & /proc/<pid>/task/<tid>/comm
+  3.7   /proc/<pid>/task/<tid>/children - Information about task children
 
   4    Configuring procfs
   4.1  Mount options
@@ -1578,6 +1579,23 @@ then the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated
 comm value.
 
 
+3.7    /proc/<pid>/task/<tid>/children - Information about task children
+-------------------------------------------------------------------------
+This file provides a fast way to retrieve first level children pids
+of a task pointed by <pid>/<tid> pair. The format is a space separated
+stream of pids.
+
+Note the "first level" here -- if a child has own children they will
+not be listed here, one needs to read /proc/<children-pid>/task/<tid>/children
+to obtain the descendants.
+
+Since this interface is intended to be fast and cheap it doesn't
+guarantee to provide precise results and some children might be
+skipped, especially if they've exited right after we printed their
+pids, so one need to either stop or freeze processes being inspected
+if precise results are needed.
+
+
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 Configuring procfs
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