RE: A question regarding "multiple SGL"

2016-10-27 Thread Steve Wise
> > Hi Robert, > > Hey Robert, Christoph, > > > please explain your use cases that isn't handled. The one and only > > reason to set MSDBD to 1 is to make the code a lot simpler given that > > there is no real use case for supporting more. > > > > RDMA uses memory registrations to register

Re: A question regarding "multiple SGL"

2016-10-27 Thread Sagi Grimberg
Hi Robert, Hey Robert, Christoph, please explain your use cases that isn't handled. The one and only reason to set MSDBD to 1 is to make the code a lot simpler given that there is no real use case for supporting more. RDMA uses memory registrations to register large and possibly

Re: A question regarding "multiple SGL"

2016-10-27 Thread Christoph Hellwig
Hi Robert, please explain your use cases that isn't handled. The one and only reason to set MSDBD to 1 is to make the code a lot simpler given that there is no real use case for supporting more. RDMA uses memory registrations to register large and possibly discontiguous data regions for a

Re: A question regarding "multiple SGL"

2016-10-27 Thread Qiuxin (robert)
Martin K. Petersen; Mike Snitzer; linux-r...@vger.kernel.org; Ming Lei; linux-n...@lists.infradead.org; Keith Busch; Doug Ledford; linux-s...@vger.kernel.org; Laurence Oberman; Christoph Hellwig; Tiger zhao; Qiuxin (robert) 主题: Re: A question regarding "multiple SGL" Hi Robert, There

Re: A question regarding "multiple SGL"

2016-10-27 Thread Christoph Hellwig
Hi Robert, There is no feature called "Multiple SGL in one NVMe capsule". The NVMe over Fabrics specification allows a controller to advertise how many SGL descriptors it supports using the MSDBD Identify field: "Maximum SGL Data Block Descriptors (MSDBD): This field indicates the maximum