[PATCH] Document Linux's memory barriers [try #2]

David Howells dhowells at redhat.com
Thu Mar 9 04:04:51 EST 2006

Alan Cox <alan at redhat.com> wrote:

> [For information on bus mastering DMA and coherency please read ....]
> sincee have a doc on this


> The use of volatile generates poorer code and hides the serialization in 
> type declarations that may be far from the code.

I'm not sure what you mean by that.

> Is this true of IA-64 ??

Are you referring to non-temporal loads and stores?

> > +There are some more advanced barriering functions:
> "barriering" ... ick,  barrier.


> Should clarify local ordering v SMP ordering for locks implied here.

Do you mean explain what each sort of lock does?

> > + (*) inX(), outX():
> > +
> > +     These are intended to talk to legacy i386 hardware using an alternate bus
> > +     addressing mode.  They are synchronous as far as the x86 CPUs are
> Not really true. Lots of PCI devices use them. Need to talk about "I/O space"

Which bit is not really true?


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