Messages in this thread Patch in this message | | | From | Davidlohr Bueso <> | Subject | [PATCH -tip/master 7/7] Documentation: Update locking/mutex-design.txt disadvantages | Date | Sun, 27 Jul 2014 22:18:44 -0700 |
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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@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
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