Commit-ID: 0a7cbf9abe3198461de3d3e97268db32a646ba06 Gitweb: http://git.kernel.org/tip/0a7cbf9abe3198461de3d3e97268db32a646ba06 Author: Davidlohr Bueso <davidlohr@xxxxxx> AuthorDate: Wed, 30 Jul 2014 13:41:56 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Wed, 13 Aug 2014 10:32:04 +0200 locking/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@xxxxxx> Acked-by: Jason Low <jason.low2@xxxxxx> Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: aswin@xxxxxx Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1406752916-3341-7-git-send-email-davidlohr@xxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- 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 ------------------- -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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