> -----Original Message----- > From: linux-nfs-owner@xxxxxxxxxxxxxxx [mailto:linux-nfs-owner@xxxxxxxxxxxxxxx] On Behalf Of Jason Gunthorpe > Sent: Monday, July 20, 2015 4:06 PM > To: Tom Talpey; Steve Wise > Cc: Chuck Lever; linux-rdma@xxxxxxxxxxxxxxx; linux-nfs@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v3 05/15] xprtrdma: Remove last ib_reg_phys_mr() call site > > On Mon, Jul 20, 2015 at 01:34:16PM -0700, Tom Talpey wrote: > > On 7/20/2015 12:03 PM, Chuck Lever wrote: > > >All HCA providers have an ib_get_dma_mr() verb. Thus > > >rpcrdma_ia_open() will either grab the device's local_dma_key if one > > >is available, or it will call ib_get_dma_mr() which is a 100% > > >guaranteed fallback. > > > > I recall that in the past, some providers did not support mapping > > all of the machine's potential physical memory with a single dma_mr. > > If an rnic did/does not support 44-ish bits of length per region, > > for example. > > Looks like you are right, but the standard in kernel is to require > ib_get_dma_mr, if the HCA can't do that, then it cannot be used on a > big memory machine with kernel ULPs. > > Looking deeper, both amso1100 and cxgb3 seem limited to 32 bits of > physical memory, and silently break all kernel ULPs if they are used > on a modern machine with > 4G. > > Is that right Steve? > Yes. > Based on that, should we remove the cxgb3 driver as well? Or at least > can you fix it up to at least fail get_dma_mr if there is too much > ram? > I would like to keep cxgb3 around. I can add code to fail if the memory is > 32b. Do you know how I get the amount of available ram? What is the process again to remove a driver? I can remove amso... > Everything else looked Ok. > > Jason > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
