Are we all talking about the same thing here? I think Christoph is just asking that the code use dma_map_[single|page|sg] instead of using page_to_phys or virt_to_phys.
The rest of this talk is about memory registration strategies which is a different issue than having the code assume that bus address == phys addresses. > On Mon, 2006-02-20 at 10:12 -0800, Caitlin Bestler wrote: > > > On 2/20/06, Roland Dreier <[EMAIL PROTECTED]> wrote: > Thomas> And, this is only one of many memory registration > Thomas> modes. We would use memory windows, if only OpenIB > Thomas> provided them (yes I know the hardware currently > sucks for > Thomas> them). We will add FMR support shortly. In both > these > Thomas> modes we perform all addressing by the book via > 1-1 OpenIB > Thomas> registration. > > Memory windows don't solve anything here, do they? You still > have to > register the full region using bus addresses somehow. > > - R. > _______________________________________________ > Keep in mind that there are two problems: registering memory and > exposing memory. > Windows solves the latter problem. FMR work requests solves both. > > A kernel based storage related client will frequently want to form > logical buffers > from scattered physical pages. The pages selected are not necessarily > part > of an existing virtual memory map, and especially not a registered > one. > > You can solve the memory registration problem once by creating an > exportable memory region that covers all of physical memory. The > problem is that you do not want to advertise that regions RKey/STag. > > Memory Windows solve that problem, by allowing you to bind windows > within the memory region. The problem is that if the buffer is not > physically > continquous then you still have to export a multi-element list in > order to > have the peer to read from a discontiguous target. > > A Fast Memory Region allows arbitrary sets of pages to form a single > logical window for the purposes of peer-to-peer interaction, and has a > life cycle that more naturally maps the duration when the pages have > to be iomapped. > > > > > > _______________________________________________ > openib-general mailing list > [email protected] > http://openib.org/mailman/listinfo/openib-general > > To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
