sched: Remove USER_SCHED from documentation
USER_SCHED has been removed, so update the documentation
accordingly.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
LKML-Reference: <4BA9A07E.8070508@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/Documentation/scheduler/sched-design-CFS.txt b/Documentation/scheduler/sched-design-CFS.txt
index 6f33593..8239ebb 100644
--- a/Documentation/scheduler/sched-design-CFS.txt
+++ b/Documentation/scheduler/sched-design-CFS.txt
@@ -211,7 +211,7 @@
desirable to first provide fair CPU time to each user on the system and then to
each task belonging to a user.
-CONFIG_GROUP_SCHED strives to achieve exactly that. It lets tasks to be
+CONFIG_CGROUP_SCHED strives to achieve exactly that. It lets tasks to be
grouped and divides CPU time fairly among such groups.
CONFIG_RT_GROUP_SCHED permits to group real-time (i.e., SCHED_FIFO and
@@ -220,38 +220,11 @@
CONFIG_FAIR_GROUP_SCHED permits to group CFS (i.e., SCHED_NORMAL and
SCHED_BATCH) tasks.
-At present, there are two (mutually exclusive) mechanisms to group tasks for
-CPU bandwidth control purposes:
-
- - Based on user id (CONFIG_USER_SCHED)
-
- With this option, tasks are grouped according to their user id.
-
- - Based on "cgroup" pseudo filesystem (CONFIG_CGROUP_SCHED)
-
- This options needs CONFIG_CGROUPS to be defined, and lets the administrator
+ These options need CONFIG_CGROUPS to be defined, and let the administrator
create arbitrary groups of tasks, using the "cgroup" pseudo filesystem. See
Documentation/cgroups/cgroups.txt for more information about this filesystem.
-Only one of these options to group tasks can be chosen and not both.
-
-When CONFIG_USER_SCHED is defined, a directory is created in sysfs for each new
-user and a "cpu_share" file is added in that directory.
-
- # cd /sys/kernel/uids
- # cat 512/cpu_share # Display user 512's CPU share
- 1024
- # echo 2048 > 512/cpu_share # Modify user 512's CPU share
- # cat 512/cpu_share # Display user 512's CPU share
- 2048
- #
-
-CPU bandwidth between two users is divided in the ratio of their CPU shares.
-For example: if you would like user "root" to get twice the bandwidth of user
-"guest," then set the cpu_share for both the users such that "root"'s cpu_share
-is twice "guest"'s cpu_share.
-
-When CONFIG_CGROUP_SCHED is defined, a "cpu.shares" file is created for each
+When CONFIG_FAIR_GROUP_SCHED is defined, a "cpu.shares" file is created for each
group created using the pseudo filesystem. See example steps below to create
task groups and modify their CPU share using the "cgroups" pseudo filesystem.
@@ -273,24 +246,3 @@
# #Launch gmplayer (or your favourite movie player)
# echo <movie_player_pid> > multimedia/tasks
-
-8. Implementation note: user namespaces
-
-User namespaces are intended to be hierarchical. But they are currently
-only partially implemented. Each of those has ramifications for CFS.
-
-First, since user namespaces are hierarchical, the /sys/kernel/uids
-presentation is inadequate. Eventually we will likely want to use sysfs
-tagging to provide private views of /sys/kernel/uids within each user
-namespace.
-
-Second, the hierarchical nature is intended to support completely
-unprivileged use of user namespaces. So if using user groups, then
-we want the users in a user namespace to be children of the user
-who created it.
-
-That is currently unimplemented. So instead, every user in a new
-user namespace will receive 1024 shares just like any user in the
-initial user namespace. Note that at the moment creation of a new
-user namespace requires each of CAP_SYS_ADMIN, CAP_SETUID, and
-CAP_SETGID.