Messages in this thread | | | Subject | Re: [PATCH 0/2] jump label: 2.6.38 updates | From | Peter Zijlstra <> | Date | Mon, 14 Feb 2011 19:24:28 +0100 |
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On Mon, 2011-02-14 at 17:50 +0000, Will Newton wrote: > > It would observe a stale value, but that value would only be updated > when the cache line was reloaded from main memory which would have to > be triggered by either eviction or cache flushing. So it could get > pretty stale. Whilst that's probably within the spec. of atomic_read I > suspect it would lead to problems in practice. I could be wrong > though.
Right, so the typical scenario that could cause pain is something like:
while (atomic_read(&foo) != n) cpu_relax();
and the problem is that cpu_relax() doesn't know which particular cacheline to flush in order to make things go faster, hm?
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