1 files changed, 0 insertions, 89 deletions
diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt
deleted file mode 100644
index c818cf65c5a9..000000000000
--- a/Documentation/RCU/rcu.txt
+++ /dev/null
@@ -1,89 +0,0 @@
-RCU Concepts
-
-
-The basic idea behind RCU (read-copy update) is to split destructive
-operations into two parts, one that prevents anyone from seeing the data
-item being destroyed, and one that actually carries out the destruction.
-A "grace period" must elapse between the two parts, and this grace period
-must be long enough that any readers accessing the item being deleted have
-since dropped their references.  For example, an RCU-protected deletion
-from a linked list would first remove the item from the list, wait for
-a grace period to elapse, then free the element.  See the listRCU.txt
-file for more information on using RCU with linked lists.
-
-
-Frequently Asked Questions
-
-o	Why would anyone want to use RCU?
-
-	The advantage of RCU's two-part approach is that RCU readers need
-	not acquire any locks, perform any atomic instructions, write to
-	shared memory, or (on CPUs other than Alpha) execute any memory
-	barriers.  The fact that these operations are quite expensive
-	on modern CPUs is what gives RCU its performance advantages
-	in read-mostly situations.  The fact that RCU readers need not
-	acquire locks can also greatly simplify deadlock-avoidance code.
-
-o	How can the updater tell when a grace period has completed
-	if the RCU readers give no indication when they are done?
-
-	Just as with spinlocks, RCU readers are not permitted to
-	block, switch to user-mode execution, or enter the idle loop.
-	Therefore, as soon as a CPU is seen passing through any of these
-	three states, we know that that CPU has exited any previous RCU
-	read-side critical sections.  So, if we remove an item from a
-	linked list, and then wait until all CPUs have switched context,
-	executed in user mode, or executed in the idle loop, we can
-	safely free up that item.
-
-	Preemptible variants of RCU (CONFIG_PREEMPT_RCU) get the
-	same effect, but require that the readers manipulate CPU-local
-	counters.  These counters allow limited types of blocking within
-	RCU read-side critical sections.  SRCU also uses CPU-local
-	counters, and permits general blocking within RCU read-side
-	critical sections.  These variants of RCU detect grace periods
-	by sampling these counters.
-
-o	If I am running on a uniprocessor kernel, which can only do one
-	thing at a time, why should I wait for a grace period?
-
-	See the UP.txt file in this directory.
-
-o	How can I see where RCU is currently used in the Linux kernel?
-
-	Search for "rcu_read_lock", "rcu_read_unlock", "call_rcu",
-	"rcu_read_lock_bh", "rcu_read_unlock_bh", "srcu_read_lock",
-	"srcu_read_unlock", "synchronize_rcu", "synchronize_net",
-	"synchronize_srcu", and the other RCU primitives.  Or grab one
-	of the cscope databases from:
-
-	http://www.rdrop.com/users/paulmck/RCU/linuxusage/rculocktab.html
-
-o	What guidelines should I follow when writing code that uses RCU?
-
-	See the checklist.txt file in this directory.
-
-o	Why the name "RCU"?
-
-	"RCU" stands for "read-copy update".  The file listRCU.txt has
-	more information on where this name came from, search for
-	"read-copy update" to find it.
-
-o	I hear that RCU is patented?  What is with that?
-
-	Yes, it is.  There are several known patents related to RCU,
-	search for the string "Patent" in RTFP.txt to find them.
-	Of these, one was allowed to lapse by the assignee, and the
-	others have been contributed to the Linux kernel under GPL.
-	There are now also LGPL implementations of user-level RCU
-	available (http://liburcu.org/).
-
-o	I hear that RCU needs work in order to support realtime kernels?
-
-	Realtime-friendly RCU can be enabled via the CONFIG_PREEMPT_RCU
-	kernel configuration parameter.
-
-o	Where can I find more information on RCU?
-
-	See the RTFP.txt file in this directory.
-	Or point your browser at http://www.rdrop.com/users/paulmck/RCU/.