> -----Original Message----- > From: Tom Talpey <tom@xxxxxxxxxx> > Sent: Friday, 21 October 2022 16:34 > To: Long Li <longli@xxxxxxxxxxxxx>; Bernard Metzler <BMT@xxxxxxxxxxxxxx>; > KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; > Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>; Wei Liu <wei.liu@xxxxxxxxxx>; > Dexuan Cui <decui@xxxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; > Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Jason > Gunthorpe <jgg@xxxxxxxx>; Leon Romanovsky <leon@xxxxxxxxxx>; > edumazet@xxxxxxxxxx; shiraz.saleem@xxxxxxxxx; Ajay Sharma > <sharmaajay@xxxxxxxxxxxxx> > Cc: linux-hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx > Subject: [EXTERNAL] Re: [Patch v8 12/12] RDMA/mana_ib: Add a driver for > Microsoft Azure Network Adapter > > On 10/20/2022 4:42 PM, Long Li wrote: > >> [Bernard wrote...] > > >>> + props->max_qp_wr = MAX_SEND_BUFFERS_PER_QUEUE; > >>> + > >>> + /* > >>> + * max_cqe could be potentially much bigger. > >>> + * As this version of driver only support RAW QP, set it to the same > >>> + * value as max_qp_wr > >>> + */ > >>> + props->max_cqe = MAX_SEND_BUFFERS_PER_QUEUE; > >>> + > >>> + props->max_mr_size = MANA_IB_MAX_MR_SIZE; > >>> + props->max_mr = INT_MAX; > >> > >> How the 24 bit wide MR keys can handle INT_MAX unique > >> MR's? > > > > Not sure if I understand this correctly, lkey and rkey are u32 in ib_mr. > > The upper 8 bits of an ib_mr remote token are reserved for use as a > rotating key, this allows a consumer to more safely reuse an ib_mr > without having to overallocate large region pools. > > Tom. Right, my point was that one cannot encode INT_MAX different MR identifiers into 32 - 8 = 24 bits. Best, Bernard.
