On Wed, Dec 08, 2010 at 12:14:51PM +0000, Walukiewicz, Miroslaw wrote: > Or, > > >I don't see why the ib uverbs flow (BTW - the data path has nothing to do > >with the > >rdma_cm, you're working with /dev/infiniband/uverbsX), can't be enhanced > >e.g to support shared-page which is allocated && mmaped from uverbs to > >user space and used in the same manner your implementation does. > > The problem that I see is that the mmap is currently used for > mapping of doorbell page in different drivers. > > We can use it for mapping a page for transmit/receive operation when > we are able to differentiate that we need to map Doorbell or our > shared page.
There is the 64 bit file offset field to mmap which I think is driver-specific. You could use 0 for the doorbell page, QPN*PAGE_SIZE + QPN_OFFSET for the per-QP page, etc.. > The second problem is that this rx/tx mmap should map the separate > page per QP to avoid the unnecessary QP lookups so page identifier > passed to mmap should be based on QP identifier. > > I cannot find a specific code for /dev/infiniband/uverbsX. Is this > device driver sharing the same functions like /dev/infiniband/rdmacm > or it has own implementation. It is in drivers/infiniband/core/uverbs* For mmap the call is just routed to the driver's ib_dev mmap function, so you can do whatever you want in your driver and match the functionality in your userspace libibverbs driver library. I think you should be able to implement your driver-specific optimization within the uverbs framework - that would be best all round. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
