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From: Nick Andrew <nick@nick-andrew.net>
To: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Pavel Emelyanov <xemul@openvz.org>,
	trivial@kernel.org, linux-kernel@vger.kernel.org,
	Serge Hallyn <serue@us.ibm.com>
Subject: [PATCH 2.6.25-rc2 3/9] config: Improve init/Kconfig help	descriptions - namespaces
Date: Wed, 20 Feb 2008 23:19:15 +1100	[thread overview]
Message-ID: <20080220121915.GA2169@tull.net> (raw)
In-Reply-To: <20080219143307.GA27352@tull.net>

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"

  parent reply	other threads:[~2008-02-20 12:19 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-19 14:06 Improve init/Kconfig help descriptions [PATCH 0/9] Nick Andrew
2008-02-19 14:09 ` Improve init/Kconfig help descriptions [PATCH 1/9] Nick Andrew
2008-02-19 14:11 ` Improve init/Kconfig help descriptions [PATCH 2/9] Nick Andrew
2008-02-19 14:33 ` Improve init/Kconfig help descriptions [PATCH 3/9] Nick Andrew
2008-02-19 14:42   ` Pavel Emelyanov
2008-02-19 15:10     ` Nick Andrew
2008-02-19 15:16       ` Pavel Emelyanov
2008-02-19 15:50         ` Serge E. Hallyn
2008-02-19 16:44         ` Randy Dunlap
2008-02-19 22:41           ` Nick Andrew
2008-02-20 12:19           ` Nick Andrew [this message]
2008-02-20 12:23             ` [PATCH 2.6.25-rc2 3/9] config: Improve init/Kconfig help descriptions - namespaces Pavel Emelyanov
2008-02-20 13:01               ` Nick Andrew
2008-02-20 13:07                 ` Pavel Emelyanov
2008-02-20 16:50             ` serge
2008-02-20 23:10               ` Nick Andrew
2008-02-19 14:38 ` Improve init/Kconfig help descriptions [PATCH 4/9] Nick Andrew
2008-02-20  3:42   ` Valdis.Kletnieks
2008-02-20 22:17     ` Nick Andrew
2008-02-19 14:53 ` Improve init/Kconfig help descriptions [PATCH 5/9] Nick Andrew
2008-02-19 20:17   ` Randy Dunlap
2008-02-19 15:12 ` Improve init/Kconfig help descriptions [PATCH 6/9] Nick Andrew
2008-02-19 15:39   ` Paul Jackson
2008-02-20 12:41     ` Nick Andrew
2008-02-20 16:43       ` Paul Jackson
2008-02-20  2:04   ` Paul Menage
2008-02-20  2:54     ` Nick Andrew
2008-02-20  3:12       ` Paul Menage
2008-02-20 16:55       ` serge
2008-02-20 21:31         ` Nick Andrew
2008-02-19 15:15 ` Improve init/Kconfig help descriptions [PATCH 7/9] Nick Andrew
2008-02-19 15:21 ` Improve init/Kconfig help descriptions [PATCH 8/9] Nick Andrew
2008-02-19 15:27 ` Improve init/Kconfig help descriptions [PATCH 9/9] Nick Andrew
2008-02-20 22:33 ` [PATCH 2.6.25-rc2 1/9] init: Improve init/Kconfig help descriptions part 1 Nick Andrew
     [not found] ` <200802220014.m1M0Dh5r022354@rgminet03.oracle.com>
2008-02-22  0:19   ` [PATCH 2.6.25-rc2 5/9] Kconfig: Improve init/Kconfig help descriptions - IKCONFIG etc Randy Dunlap
2008-02-22  0:48 ` [PATCH 2.6.25-rc2 1/9] Kconfig: Improve init/Kconfig help descriptions part 1 Nick Andrew
2008-02-22  0:49 ` [PATCH 2.6.25-rc2 2/9] Kconfig: Improve init/Kconfig help descriptions - TASKSTATS Nick Andrew
2008-02-22  0:51 ` [PATCH 2.6.25-rc2 3/9] Kconfig: Improve init/Kconfig help descriptions - NAMESPACES Nick Andrew
2008-02-27 23:00   ` Nick Andrew
2008-02-27 23:08     ` Serge E. Hallyn
2008-02-22  0:52 ` [PATCH 2.6.25-rc2 4/9] Kconfig: Improve init/Kconfig help descriptions - AUDIT Nick Andrew
2008-02-22  0:54 ` [PATCH 2.6.25-rc2 5/9] Kconfig: Improve init/Kconfig help descriptions - IKCONFIG etc Nick Andrew
2008-02-22  0:55 ` [PATCH 2.6.25-rc2 6/9] Kconfig: Improve init/Kconfig help descriptions - CGROUPS Nick Andrew
2008-02-22  0:56 ` [PATCH 2.6.25-rc2 7/9] Kconfig: Improve init/Kconfig help descriptions - EMBEDDED etc Nick Andrew
2008-02-22  0:58 ` [PATCH 2.6.25-rc2 8/9] Kconfig: Improve init/Kconfig help descriptions - SLAB Nick Andrew
2008-02-22  0:59 ` [PATCH 2.6.25-rc2 9/9] Kconfig: Improve init/Kconfig help descriptions - MODULES Nick Andrew
     [not found] ` <200802220010.m1M0Arr7024044@vzorg.swsoft.net>
2008-02-22  8:14   ` [PATCH 2.6.25-rc2 3/9] Kconfig: Improve init/Kconfig help descriptions - NAMESPACES Pavel Emelyanov
     [not found] ` <200802220010.m1M0Auqn024414@e5.ny.us.ibm.com>
2008-02-22 22:14   ` Serge E. Hallyn
2008-02-23  1:12     ` Nick Andrew
2008-02-23  3:45       ` Serge E. Hallyn

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