[PATCH -tip/master 7/7] Documentation: Update locking/mutex-design.txt disadvantages

From: Davidlohr Bueso
Date: Mon Jul 28 2014 - 01:19:22 EST


Fortunately Jason was able to reduce some of the overhead we
had introduced in the original rwsem optimistic spinning -
an it is now the same size as mutexes. Update the documentation
accordingly.

Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
---
Documentation/locking/mutex-design.txt | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/locking/mutex-design.txt b/Documentation/locking/mutex-design.txt
index ee231ed..60c482d 100644
--- a/Documentation/locking/mutex-design.txt
+++ b/Documentation/locking/mutex-design.txt
@@ -145,9 +145,9 @@ Disadvantages

Unlike its original design and purpose, 'struct mutex' is larger than
most locks in the kernel. E.g: on x86-64 it is 40 bytes, almost twice
-as large as 'struct semaphore' (24 bytes) and 8 bytes shy of the
-'struct rw_semaphore' variant. Larger structure sizes mean more CPU
-cache and memory footprint.
+as large as 'struct semaphore' (24 bytes) and tied, along with rwsems,
+for the largest lock in the kernel. Larger structure sizes mean more
+CPU cache and memory footprint.

When to use mutexes
-------------------
--
1.8.1.4

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