On Wed, Feb 05, 2025 at 11:54:05AM +0530, Bharata B Rao wrote: > Here is a compilation of available temperature sources and how the > hot/access data is consumed by different subsystems: > > PA-Physical address available > VA-Virtual address available > AA-Access time available > NA-accessing Node info available > > I have left the slot blank for those which I am not sure about. > ================================================== > Temperature PA VA AA NA > source > ================================================== > PROT_NONE faults Y Y Y Y > -------------------------------------------------- > folio_mark_accessed() Y Y Y > -------------------------------------------------- > PTE A bit Y Y N N > -------------------------------------------------- > Platform hints Y Y Y Y > (AMD IBS) > -------------------------------------------------- > Device hints Y > (CXL HMU) > ================================================== > > And here is an attempt to compile how different subsystems > use the above data: > ============================================================== > Source Subsystem Consumption > ============================================================== > PROT_NONE faults NUMAB NUMAB=1 locality based > via process pgtable balancing > walk NUMAB=2 hot page > promotion > ============================================================== > folio_mark_accessed() FS/filemap/GUP LRU list activation > ============================================================== > PTE A bit via Reclaim:LRU LRU list activation, > rmap walk deactivation/demotion > ============================================================== > PTE A bit via Reclaim:MGLRU LRU list activation, > rmap walk and process deactivation/demotion > pgtable walk > ============================================================== > PTE A bit via DAMON LRU activation, > rmap walk hot page promotion, > demotion etc > ============================================================== > Platform hints NUMAB NUMAB=1 Locality based > (AMD IBS) balancing and > NUMAB=2 hot page > promotion > ============================================================== > Device hints NUMAB NUMAB=2 hot page > promotion > ============================================================== > The last two are listed as possibilities. > > Feel free to correct/clarify and add more. There's PG_young / PG_idle as well.
