Re: [PATCH 05/12] net: mana: Set the DMA device max page size

From: Jason Gunthorpe
Date: Tue May 17 2022 - 11:00:00 EST


On Tue, May 17, 2022 at 02:04:29AM -0700, longli@xxxxxxxxxxxxxxxxx wrote:
> From: Long Li <longli@xxxxxxxxxxxxx>
>
> The system chooses default 64K page size if the device does not specify
> the max page size the device can handle for DMA. This do not work well
> when device is registering large chunk of memory in that a large page size
> is more efficient.
>
> Set it to the maximum hardware supported page size.

For RDMA devices this should be set to the largest segment size an
ib_sge can take in when posting work. It should not be the page size
of MR. 2M is a weird number for that, are you sure it is right?

Jason