On Tue 05-12-23 14:32:20, Srinivasulu Thanneeru wrote: > > > On 12/5/2023 2:21 PM, Michal Hocko wrote: > > CAUTION: EXTERNAL EMAIL. Do not click links or open attachments unless you recognize the sender and were expecting this message. > > > > > > On Tue 05-12-23 14:12:17, Srinivasulu Thanneeru wrote: > > > > > > > > > On 12/5/2023 2:05 PM, Michal Hocko wrote: > > > > CAUTION: EXTERNAL EMAIL. Do not click links or open attachments unless you recognize the sender and were expecting this message. > > > > > > > > > > > > On Tue 05-12-23 01:26:07, Srinivasulu Thanneeru wrote: > > > > > > > > > > > > > > > On 12/4/2023 9:13 PM, Michal Hocko wrote: > > > > > > CAUTION: EXTERNAL EMAIL. Do not click links or open attachments unless you recognize the sender and were expecting this message. > > > > > > > > > > > > > > > > > > On Fri 01-12-23 03:34:20, sthanneeru.opensrc@xxxxxxxxxx wrote: > > > > > > > From: Srinivasulu Thanneeru <sthanneeru.opensrc@xxxxxxxxxx> > > > > > > > > > > > > > > The memory tiers feature allows nodes with similar memory types > > > > > > > or performance characteristics to be grouped together in a > > > > > > > memory tier. However, there is currently no provision for > > > > > > > moving a node from one tier to another on demand. > > > > > > > > > > > > Could you expand on why this is really needed/necessary? What is the > > > > > > actual usecase? > > > > > > > > > > Hi Michal Hock, > > > > > > > > > > Following two use-cases we have observed. > > > > > 1. It is not accurate to group similar memory types in the same tier, > > > > > because even similar memory types may have different speed grades. > > > > > > > > Presumably they are grouped based on a HW configuration. Does that mean > > > > that the configuration is wrong? Are you trying to workaround that by > > > > this interface? > > > > > > > > > 2. Some systems boots up with CXL devices and DRAM on the same memory-tier, > > > > > we need a way to move the CXL nodes to the correct tier from the user space. > > > > > > > > Again, could you expand a bit more and explain why this cannot be > > > > configured automatically? > > > > > > Yes, in both cases above, if hardware not automatically populated properly, > > > in that case this interface would help to correct it from user space. > > > > > > We had observed case-2 in our setups. > > > > How hard it is to address this at the HW level? > > > > Btw. this is really important piece of context that should be part of > > the changelog. Quite honestly introducing user interfaces solely to > > workaround HW issues seems a rather weak justification. Are there any > > usecases you can think of where this would be useful? > > I'm not sure how difficult to fix it in the hardware. Please explore that. It is sad to see learn that CXL which is a really new technology is already fighting with misconfigurations. -- Michal Hocko SUSE Labs
