On Tue, May 22, 2012 at 08:56:12AM +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2012-05-22 at 01:22 +0300, Michael S. Tsirkin wrote:
> > > Again, from which originator ? From a given initiator, nothing
> > bypasses
> > > anything, so the right thing to do here is a full mb(). However, I
> > > sus
On Tue, 22 May 2012 07:58:17 +1000, Benjamin Herrenschmidt
wrote:
> On Mon, 2012-05-21 at 15:18 +0300, Michael S. Tsirkin wrote:
> > But I can also live with a global flag "latest_dma_read"
> > and on read we could do
> > if (unlikely(latest_dma_read))
> > smp_mb();
> >
> > if yo
On Tue, 2012-05-22 at 01:22 +0300, Michael S. Tsirkin wrote:
> > Again, from which originator ? From a given initiator, nothing
> bypasses
> > anything, so the right thing to do here is a full mb(). However, I
> > suspect what you are talking about here is read -responses- not
> > bypassing writes
On Tue, 2012-05-22 at 01:22 +0300, Michael S. Tsirkin wrote:
> > Again, from which originator ? From a given initiator, nothing
> bypasses
> > anything, so the right thing to do here is a full mb(). However, I
> > suspect what you are talking about here is read -responses- not
> > bypassing writes
On Tue, May 22, 2012 at 07:58:17AM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2012-05-21 at 15:18 +0300, Michael S. Tsirkin wrote:
>
> > > mb is more than just "read flush writes" (besides it's not a statement
> > > about flushing, it's a statement about ordering. whether it has a
> > > flushi
On Mon, 2012-05-21 at 15:18 +0300, Michael S. Tsirkin wrote:
> > mb is more than just "read flush writes" (besides it's not a statement
> > about flushing, it's a statement about ordering. whether it has a
> > flushing side effect on x86 is a separate issue, it doesn't on power for
> > example).
>
