[PATCH 2.6.25-rc2 3/9] Kconfig: Improve init/Kconfig help descriptions - NAMESPACES

From: Nick Andrew
Date: Wed Feb 27 2008 - 18:01:39 EST


Modify the help descriptions of init/Kconfig for clarity, accuracy and consistency.

Kernel config options affected:

- NAMESPACES
- UTS_NS
- IPC_NS
- USER_NS
- PID_NS

Add a brief description of what namespaces are and when you would
want to use them.

For the *_NS options, add a tiny bit of detail about what it is,
and ensure each config option has an answer hint: Y for namespaces
"if you will be using a container system", Y for the *_NS options
except for the two labeled EXPERIMENTAL.

Signed-off-by: Nick Andrew <nick@xxxxxxxxxxxxxxx>
---
Try #4


init/Kconfig | 65 +++++++++++++++++++++++++++++++++++++++++++++-------------
1 files changed, 50 insertions(+), 15 deletions(-)


diff --git a/init/Kconfig b/init/Kconfig
index cc7a341..0e6a084 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -487,31 +487,62 @@ config NAMESPACES
bool "Namespaces support" if EMBEDDED
default !EMBEDDED
help
- Provides the way to make tasks work with different objects using
- the same id. For example same IPC id may refer to different objects
- or same user id or pid may refer to different tasks when used in
- different namespaces.
+ Select various namespace options.
+
+ Namespaces allow different kernel objects (such as processes
+ or sockets) to have the same ID in different namespaces.
+ Identifiers like process IDs, which historically were globally
+ unique, will now be unique only within each PID namespace.
+ Each task can refer only to PIDs within the same namespace
+ as the task itself.
+
+ Namespaces are used by container systems (e.g. vservers)
+ to provide isolation between the containers.
+
+ This option does not affect any kernel code directly; it merely
+ allows you to select namespace options below.
+
+ Answer Y if you will be using a container system, and you
+ will probably want to enable all the namespace options
+ below.

config UTS_NS
bool "UTS namespace"
depends on NAMESPACES
help
- In this namespace tasks see different info provided with the
- uname() system call
+ Enable support for multiple UTS system attributes.
+
+ Each UTS namespace provides an individual view of the
+ information returned by the uname() system call including
+ hostname, kernel version and domain name.
+
+ Answer Y if you will be using a container system.

config IPC_NS
bool "IPC namespace"
depends on NAMESPACES && SYSVIPC
help
- In this namespace tasks work with IPC ids which correspond to
- different IPC objects in different namespaces
+ Enable support for namespace-specific IPC IDs.
+
+ IPC IDs will be unique only within each IPC namespace.
+
+ Answer Y if you will be using a container system.

config USER_NS
bool "User namespace (EXPERIMENTAL)"
depends on NAMESPACES && EXPERIMENTAL
help
- This allows containers, i.e. vservers, to use user namespaces
- to provide different user info for different servers.
+ Enable experimental support for user namespaces.
+
+ This is a function used by container-based virtualisation systems
+ (e.g. vservers). User namespaces are intended to ensure that
+ processes with the same uid which are in different containers are
+ isolated from each other.
+
+ Currently user namespaces provide separate accounting, while
+ isolation must be provided using SELinux or a custom security
+ module.
+
If unsure, say N.

config PID_NS
@@ -519,12 +550,16 @@ config PID_NS
default n
depends on NAMESPACES && EXPERIMENTAL
help
- Suport process id namespaces. This allows having multiple
- process with the same pid as long as they are in different
- pid namespaces. This is a building block of containers.
+ Enable experimental support for hierarchical process id namespaces.
+
+ This is a function used by container-based virtualisation
+ systems (e.g. vservers). Each process will have a distinct
+ Process ID in each PID namespace which the process is in.
+ A process can "see" other processes in the same PID namespace
+ and child PID namespaces, but cannot see processes in parent
+ PID namespaces.

- Unless you want to work with an experimental feature
- say N here.
+ If unsure, say N.

config BLK_DEV_INITRD
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"

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