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* [tip:core/locking] Documentation/memory-barriers.txt: Fix a typo in the data dependency description
@ 2013-11-22 12:31 tip-bot for Ingo Molnar
  2013-11-22 13:57 ` Paul E. McKenney
  0 siblings, 1 reply; 2+ messages in thread
From: tip-bot for Ingo Molnar @ 2013-11-22 12:31 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: linux-kernel, hpa, mingo, torvalds, a.p.zijlstra, paulmck, akpm,
	tglx

Commit-ID:  e0edc78f25c020dea66742c05a7fbcb2ff3df629
Gitweb:     http://git.kernel.org/tip/e0edc78f25c020dea66742c05a7fbcb2ff3df629
Author:     Ingo Molnar <mingo@kernel.org>
AuthorDate: Fri, 22 Nov 2013 11:24:53 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 22 Nov 2013 11:46:12 +0100

Documentation/memory-barriers.txt: Fix a typo in the data dependency description

This typo has been there forever, it is 7.5 years old, looks like this
section of our memory ordering documentation is a place where most eyes
are glazed over already ;-)

[ Also fix some stray spaces and stray tabs while at it, shrinking the
  file by 49 bytes. Visual output unchanged. ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-gncea9cb8igosblizfqMXrie@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 Documentation/memory-barriers.txt | 42 +++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index c8c42e6..020cccd 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -500,7 +500,7 @@ odd-numbered bank is idle, one can see the new value of the pointer P (&B),
 but the old value of the variable B (2).
 
 
-Another example of where data dependency barriers might by required is where a
+Another example of where data dependency barriers might be required is where a
 number is read from memory and then used to calculate the index for an array
 access:
 
@@ -882,12 +882,12 @@ cache it for later use.
 
 Consider:
 
-	CPU 1	   		CPU 2
+	CPU 1			CPU 2
 	=======================	=======================
-	 	   		LOAD B
-	 	   		DIVIDE		} Divide instructions generally
-	 	   		DIVIDE		} take a long time to perform
-	 	   		LOAD A
+				LOAD B
+				DIVIDE		} Divide instructions generally
+				DIVIDE		} take a long time to perform
+				LOAD A
 
 Which might appear as this:
 
@@ -910,13 +910,13 @@ Which might appear as this:
 Placing a read barrier or a data dependency barrier just before the second
 load:
 
-	CPU 1	   		CPU 2
+	CPU 1			CPU 2
 	=======================	=======================
-	 	   		LOAD B
-	 	   		DIVIDE
-	 	   		DIVIDE
+				LOAD B
+				DIVIDE
+				DIVIDE
 				<read barrier>
-	 	   		LOAD A
+				LOAD A
 
 will force any value speculatively obtained to be reconsidered to an extent
 dependent on the type of barrier used.  If there was no change made to the
@@ -1887,8 +1887,8 @@ functions:
      space should suffice for PCI.
 
      [*] NOTE! attempting to load from the same location as was written to may
-     	 cause a malfunction - consider the 16550 Rx/Tx serial registers for
-     	 example.
+	 cause a malfunction - consider the 16550 Rx/Tx serial registers for
+	 example.
 
      Used with prefetchable I/O memory, an mmiowb() barrier may be required to
      force stores to be ordered.
@@ -1955,19 +1955,19 @@ barriers for the most part act at the interface between the CPU and its cache
 	                          :
 	+--------+    +--------+  :   +--------+    +-----------+
 	|        |    |        |  :   |        |    |           |    +--------+
-	|  CPU   |    | Memory |  :   | CPU    |    |           |    |	      |
-	|  Core  |--->| Access |----->| Cache  |<-->|           |    |	      |
+	|  CPU   |    | Memory |  :   | CPU    |    |           |    |        |
+	|  Core  |--->| Access |----->| Cache  |<-->|           |    |        |
 	|        |    | Queue  |  :   |        |    |           |--->| Memory |
-	|        |    |        |  :   |        |    |           |    |	      |
-	+--------+    +--------+  :   +--------+    |           |    | 	      |
+	|        |    |        |  :   |        |    |           |    |        |
+	+--------+    +--------+  :   +--------+    |           |    |        |
 	                          :                 | Cache     |    +--------+
 	                          :                 | Coherency |
 	                          :                 | Mechanism |    +--------+
 	+--------+    +--------+  :   +--------+    |           |    |	      |
 	|        |    |        |  :   |        |    |           |    |        |
 	|  CPU   |    | Memory |  :   | CPU    |    |           |--->| Device |
-	|  Core  |--->| Access |----->| Cache  |<-->|           |    | 	      |
-	|        |    | Queue  |  :   |        |    |           |    | 	      |
+	|  Core  |--->| Access |----->| Cache  |<-->|           |    |        |
+	|        |    | Queue  |  :   |        |    |           |    |        |
 	|        |    |        |  :   |        |    |           |    +--------+
 	+--------+    +--------+  :   +--------+    +-----------+
 	                          :
@@ -2090,7 +2090,7 @@ CPU's caches by some other cache event:
 	p = &v;		q = p;
 			<D:request p>
 	<B:modify p=&v>	<D:commit p=&v>
-		  	<D:read p>
+			<D:read p>
 			x = *q;
 			<C:read *q>	Reads from v before v updated in cache
 			<C:unbusy>
@@ -2115,7 +2115,7 @@ queue before processing any further requests:
 	p = &v;		q = p;
 			<D:request p>
 	<B:modify p=&v>	<D:commit p=&v>
-		  	<D:read p>
+			<D:read p>
 			smp_read_barrier_depends()
 			<C:unbusy>
 			<C:commit v=2>

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2013-11-22 12:31 [tip:core/locking] Documentation/memory-barriers.txt: Fix a typo in the data dependency description tip-bot for Ingo Molnar
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