Messages in this thread | | | Subject | Re: [ANNOUNCE] mdb: Merkey's Linux Kernel Debugger 2.6.27-rc4 released | From | Peter Zijlstra <> | Date | Thu, 21 Aug 2008 13:02:48 +0200 |
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On Thu, 2008-08-21 at 12:57 +0200, Stefan Richter wrote: > Peter Zijlstra wrote: > > On Wed, 2008-08-20 at 20:50 -0600, jmerkey@wolfmountaingroup.com wrote: > > > >> volatiles left in the code due to the previously stated > >> (and still present) severe breakage of the GNU compiler with SMP > >> shared data. most of the barrier() functions are just plain broken > >> and do not result in proper compiler behavior in this tree. > > > > Can you provide explicit detail? > > > > By using barrier() the compiler should clobber all its memory and > > registers therefore forcing a write/reload of the variable. > > I hope Jeff didn't try mere barrier()s only. smp_wmb() and smp_rmb() > are the more relevant barrier variants for mdb, from what I remember > when I last looked at it.
Sure, but volatile isn't a replacement for memory barriers.
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