From c775bca2c4451be4cdcf823919fa5dd9008d5c74 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Mon, 25 Apr 2016 10:28:23 +0200 Subject: [PATCH] cgroups.7: Add a section noting the "tasks" versus "processes" distinction Signed-off-by: Michael Kerrisk --- man7/cgroups.7 | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/man7/cgroups.7 b/man7/cgroups.7 index 892b591da..279060919 100644 --- a/man7/cgroups.7 +++ b/man7/cgroups.7 @@ -130,6 +130,23 @@ that are supported under version 2, while also using version 1 controllers where version 2 does not yet support those controllers. .\" +.SS Tasks versus processes +In cgroups v1, a distinction is drawn between +.I processes +and +.IR tasks . +In this view, a process can consist of multiple tasks +(more commonly called threads, from a user-space perspective). +In cgroups v1, it is possible independently manipulate +the cgroup memberships of the tasks in a process. +Because this ability caused certain problems, +.\" FIXME Add some text describing why this was a problem. +the ability to independently manipulate the cgroup memberships +of the tasks in a process has been removed in cgroups v2. +Cgroups v2 allows manipulation of cgroup membership only for processes +(which has the effect of changing the cgroup membership of +all tasks in the process). +.\" .SS Mounting To be available, a given cgroup subsystem must be compiled into the kernel.