From: Davidlohr Bueso <davidlohr@hp.com>
To: peterz@infradead.org, mingo@kernel.org
Cc: jason.low2@hp.com, davidlohr@hp.com, aswin@hp.com,
linux-kernel@vger.kernel.org
Subject: [PATCH -tip v2 7/7] Documentation: Update locking/mutex-design.txt disadvantages
Date: Wed, 30 Jul 2014 13:41:56 -0700 [thread overview]
Message-ID: <1406752916-3341-7-git-send-email-davidlohr@hp.com> (raw)
In-Reply-To: <1406752916-3341-1-git-send-email-davidlohr@hp.com>
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.
Acked-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Davidlohr Bueso <davidlohr@hp.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
next prev parent reply other threads:[~2014-07-30 20:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-30 20:41 [PATCH -tip v2 1/7] locking/mutex: Standardize arguments in lock/unlock slowpaths Davidlohr Bueso
2014-07-30 20:41 ` [PATCH -tip v2 2/7] locking/mutex: Document quick lock release when unlocking Davidlohr Bueso
2014-08-13 10:55 ` [tip:locking/core] locking/mutexes: " tip-bot for Davidlohr Bueso
2014-07-30 20:41 ` [PATCH -tip v2 3/7] locking/mcs: Remove obsolete comment Davidlohr Bueso
2014-08-13 10:55 ` [tip:locking/core] " tip-bot for Davidlohr Bueso
2014-07-30 20:41 ` [PATCH -tip v2 4/7] locking/mutex: Refactor optimistic spinning code Davidlohr Bueso
2014-07-31 0:56 ` Jason Low
2014-08-13 10:55 ` [tip:locking/core] locking/mutexes: " tip-bot for Davidlohr Bueso
2014-07-30 20:41 ` [PATCH -tip v2 5/7] locking/mutex: Use MUTEX_SPIN_ON_OWNER when appropriate Davidlohr Bueso
2014-08-13 10:55 ` [tip:locking/core] locking/mutexes: " tip-bot for Davidlohr Bueso
2014-07-30 20:41 ` [PATCH -tip v2 6/7] locking: Move docs into Documentation/locking/ Davidlohr Bueso
2014-07-30 21:02 ` Randy Dunlap
2014-07-31 6:53 ` Peter Zijlstra
2014-08-13 10:56 ` [tip:locking/core] locking/Documentation: Move locking related " tip-bot for Davidlohr Bueso
2014-07-30 20:41 ` Davidlohr Bueso [this message]
2014-08-13 10:56 ` [tip:locking/core] locking/Documentation: Update locking/ mutex-design.txt disadvantages tip-bot for Davidlohr Bueso
2014-08-13 10:54 ` [tip:locking/core] locking/mutexes: Standardize arguments in lock /unlock slowpaths tip-bot for Davidlohr Bueso
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