Messages in this thread | | | Date | Mon, 25 Jun 2018 14:28:50 +0200 | From | Andrea Parri <> | Subject | Re: [PATCH] doc: Update wake_up() & co. memory-barrier guarantees |
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On Mon, Jun 25, 2018 at 01:12:45PM +0100, David Howells wrote: > Peter Zijlstra <peterz@infradead.org> wrote: > > > So yes, I suppose we're entirely suck with the full memory barrier > > semantics like that. But I still find it easier to think of it like a > > RELEASE that pairs with the ACQUIRE of waking up, such that the task > > is guaranteed to observe it's own wake condition. > > > > And maybe that is the thing I'm missing here. These comments only state > > that it does in fact imply a full memory barrier, but do not explain > > why, should it? > > I think because RELEASE and ACQUIRE concepts didn't really exist in Linux at > the time I wrote the doc, so the choices were read/readdep, write or full. > > Since this document defines the *minimum* you can expect rather than what the > kernel actually gives you, I think it probably makes sense to switch to > RELEASE and ACQUIRE here.
RELEASE and ACQUIRE are not enough in SB. Can you elaborate?
Andrea
> > David
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