[PATCH] Document Linux's memory barriers

Nick Piggin nickpiggin at yahoo.com.au
Wed Mar 8 18:41:30 EST 2006

Paul Mackerras wrote:
> David Howells writes:

>>+     The way to deal with this is to insert an I/O memory barrier between the
>>+     two accesses:
>>+	*ADR = ctl_reg_3;
>>+	mb();
>>+	reg = *DATA;
> Ummm, this implies mb() is "an I/O memory barrier".  I can see people
> getting confused if they read this and then see mb() being used when
> no I/O is being done.

Isn't it? Why wouldn't you just use smp_mb() if no IO is being done?

SUSE Labs, Novell Inc.
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