centos man page for proc_flush_task

PROC_FLUSH_TASK(9)						The proc filesystem						PROC_FLUSH_TASK(9)

NAME
       proc_flush_task - Remove dcache entries for task from the /proc dcache.

SYNOPSIS
       void proc_flush_task(struct task_struct * task);

ARGUMENTS
       task
	   task that should be flushed.

DESCRIPTION
       When flushing dentries from proc, one needs to flush them from global proc (proc_mnt) and from all the namespaces' procs this task was seen
       in. This call is supposed to do all of this job.

       Looks in the dcache for /proc/pid /proc/tgid/task/pid if either directory is present flushes it and all of it'ts children from the dcache.

       It is safe and reasonable to cache /proc entries for a task until that task exits. After that they just clog up the dcache with useless
       entries, possibly causing useful dcache entries to be flushed instead. This routine is proved to flush those useless dcache entries at
       process exit time.

NOTE
       This routine is just an optimization so it does not guarantee that no dcache entries will exist at process exit time it just makes it very
       unlikely that any will persist.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							PROC_FLUSH_TASK(9)