Re: [PATCH 6/24] make atomic_read() behave consistently on frv

From: Segher Boessenkool
Date: Wed Aug 15 2007 - 15:48:34 EST


Well if there is only one memory location involved, then smp_rmb()
isn't
going to really do anything anyway, so it would be incorrect to use it.

rmb() orders *any* two reads; that includes two reads from the same
location.

If the two reads are to the same location, all CPUs I am aware of
will maintain the ordering without need for a memory barrier.

That's true of course, although there is no real guarantee for that.


Segher

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