Rewrite the help descriptions for clarity, accuracy and consistency.
Kernel config options affected:
- NAMESPACES
- UTS_NS
- IPC_NS
- USER_NS
- PID_NS
Signed-off-by: Nick Andrew <nick@nick-andrew.net>
---
Here's try #2 at the 3rd patch in the series, for namespace
descriptions. Patching against Linus' git tree now, and trying
to comply with the standards for submitting patches. Each of
the UTS/IPC/USER/PID descriptions is subtly different, but I
hope they all are clear and accurate.
--- a/init/Kconfig 2008-02-20 09:34:48.000000000 +1100
+++ b/init/Kconfig 2008-02-20 22:55:41.000000000 +1100
@@ -414,31 +414,71 @@
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 (i.e. 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.
+
+ This is used by container systems (i.e. vservers) so that
+ each container has its own hostname and other attributes.
+ Tasks in the container are placed in the UTS namespace
+ corresponding to the container.
+
+ 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.
+
+ This is used by container systems (i.e. vservers).
+ Tasks in the container are placed in the IPC namespace
+ corresponding to the container.
+
+ 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
@@ -446,12 +486,20 @@
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.
- Unless you want to work with an experimental feature
- say N here.
+ Process IDs will be unique only within each PID namespace.
+ This allows multiple processes to have the same PID
+ so long as they are in different PID namespaces. Furthermore,
+ each process will have a distinct PID in each namespace
+ the process is in.
+
+ This is used by container systems (i.e. vservers).
+ Tasks in the container are placed in the PID namespace
+ corresponding to the container, and can only see or
+ affect processes in the same PID namespace.
+
+ If unsure, say N.
config BLK_DEV_INITRD
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
--
