Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> writes: > On Fri, 03 Nov 2023 15:45:13 +0800 > "Huang, Ying" <ying.huang@xxxxxxxxx> wrote: > >> Gregory Price <gregory.price@xxxxxxxxxxxx> writes: >> >> > On Thu, Nov 02, 2023 at 10:47:33AM +0100, Michal Hocko wrote: >> >> On Wed 01-11-23 12:58:55, Gregory Price wrote: >> >> > Basically consider: `numactl --interleave=all ...` >> >> > >> >> > If `--weights=...`: when a node hotplug event occurs, there is no >> >> > recourse for adding a weight for the new node (it will default to 1). >> >> >> >> Correct and this is what I was asking about in an earlier email. How >> >> much do we really need to consider this setup. Is this something nice to >> >> have or does the nature of the technology requires to be fully dynamic >> >> and expect new nodes coming up at any moment? >> >> >> > >> > Dynamic Capacity is expected to cause a numa node to change size (in >> > number of memory blocks) rather than cause numa nodes to come and go, so >> > maybe handling the full node hotplug is a bit of an overreach. >> >> Will node max bandwidth change with the number of memory blocks? > > Typically no as even a single memory extent would probably be interleaved > across all the actual memory devices (think DIMMS for simplicity) within > a CXL device. I guess a device 'could' do some scaling based on capacity > provided to a particular host but feels like they should be separate controls. > I don't recall there being anything in the specification to suggest the > need to recheck the CDAT info for updates when DC add / remove events happen. Sounds good! Thank you for detailed explanation. > Mind you, who knows in future :) We'll point out in relevant forums that > doing so would be very hard to handle cleanly in Linux. Thanks! -- Best Regards, Huang, Ying
