Messages in this thread | | | Date | Mon, 14 Dec 2015 21:31:54 +0100 | From | Peter Zijlstra <> | Subject | Re: Commit 81a43adae3b9 (locking/mutex: Use acquire/release semantics) causing failures on arm64 (ThunderX) |
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On Mon, Dec 14, 2015 at 06:49:31PM +0000, One Thousand Gnomes wrote: > > But seriously are there any cases we actually care about this for osq ?
So I think what PaulMck is worried about is that one would expect things like:
mutex_lock(); MMIO(++var); mutex_unlock();
(the same example Linus gave but with a mutex instead of a spinlock) to just work.
Now, I haven't checked the code, but I'm not sure we ever rely on osq to provide the mutex ACQUIRE barrier, since we always need to acquire the mutex variable itself after we've acquired the osq 'lock'.
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