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Message-Id: <1406524724-17946-7-git-send-email-davidlohr@hp.com>
Date: Sun, 27 Jul 2014 22:18:44 -0700
From: Davidlohr Bueso <davidlohr@...com>
To: peterz@...radead.org, mingo@...nel.org
Cc: jason.low2@...com, davidlohr@...com, aswin@...com,
linux-kernel@...r.kernel.org
Subject: [PATCH -tip/master 7/7] Documentation: Update locking/mutex-design.txt disadvantages
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@...com>
---
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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