Messages in this thread | | | Date | Fri, 7 Nov 2008 15:08:12 -0500 (EST) | From | Steven Rostedt <> | Subject | Re: [RFC patch 08/18] cnt32_to_63 should use smp_rmb() |
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On Fri, 7 Nov 2008, Mathieu Desnoyers wrote: > > I want to make sure > > __m_cnt_hi > is read before > mmio cnt_lo read
Hmm, let me make sure I understand why there is no wmb.
Paul, can you verify this?
Mathieu, you do the following:
read a smp_rmb reab b if (test b) write a
So the idea is that you must read b to test it. And since we must read a before reading b we can see that we write a before either?
The question remains, can the write happen before either of the reads?
But since the read b is reading the hw clock, perhaps that just implies a wmb on the hardware side?
-- Steve
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