Re: [PATCH] seqlock: don't smp_rmb in seqlock reader spin loop

2011-05-12 Thread Andi Kleen
On Thu, May 12, 2011 at 04:13:54AM -0500, Milton Miller wrote: > > Move the smp_rmb after cpu_relax loop in read_seqlock and add > ACCESS_ONCE to make sure the test and return are consistent. > > A multi-threaded core in the lab didn't like the update Which core was that? -Andi

Re: [PATCH] seqlock: don't smp_rmb in seqlock reader spin loop

2011-05-12 Thread Eric Dumazet
Le jeudi 12 mai 2011 à 04:13 -0500, Milton Miller a écrit : > Move the smp_rmb after cpu_relax loop in read_seqlock and add > ACCESS_ONCE to make sure the test and return are consistent. > > A multi-threaded core in the lab didn't like the update > from 2.6.35 to 2.6.36, to the point it would hang