Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [RFC patch] spindep: add cross cache lines checking | Date | Mon, 5 Mar 2012 09:41:56 +0000 |
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On Monday 05 March 2012, Alex Shi wrote: > Subject: [PATCH] lockdep: add cross cache lines checking > > Modern x86 CPU won't hold whole memory bus when executing 'lock' > prefixed instructions unless the instruction destination is crossing 2 > cache lines. If so, it is disaster of system performance. > > Actually if the lock is not in the 'packed' structure, gcc places it > safely under x86 arch. But seems add this checking in > CONFIG_DEBUG_LOCK_ALLOC is harmless.
Have you tried making this a compile-time check using __alignof__? I would say that any spinlock in a packed data structure is basically a bug, even more so on most other architectures besides x86.
Arnd
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