Messages in this thread | | | Date | Mon, 5 Mar 2012 11:43:11 +0100 | From | Ingo Molnar <> | Subject | Re: [RFC patch] spindep: add cross cache lines checking |
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* Arnd Bergmann <arnd@arndb.de> wrote:
> 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.
agreed.
Thanks,
Ingo
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