[RFC PATCH V3 00/17] mm: slowtier page promotion based on PTE A bit

Raghavendra K T
2025-08-21T15:24:56Z

On 8/14/2025 9:02 PM, Raghavendra K T wrote:
> The current series has additional enhancements and comments' incorporation on top of
> RFC V2.
>
> This is an additional source of hot page generator to NUMAB, IBS [4], KMGLRUD [5].
>
> Introduction:
> =============
> In the current hot page promotion, all the activities including the
> process address space scanning, NUMA hint fault handling and page
> migration is performed in the process context. i.e., scanning overhead is
> borne by applications.
>
> This RFC V2 patch series does slow-tier page promotion by using PTE Accessed
> bit scanning. Scanning is done by a global kernel thread which routinely
> scans all the processes' address spaces and checks for accesses by reading
> the PTE A bit.
>
> A separate migration thread migrates/promotes the pages to the top-tier
> node based on a simple heuristic that uses top-tier scan/access information
> of the mm.
>
> Additionally based on the feedback, a prctl knob with a scalar value is
> provided to control per task scanning.

Patches are also available in the branch:

https://github.com/AMDESE/linux-mm/tree/rkt/kscand_rfc_v3

[...]

>
>
> base-commit: 038d61fd642278bab63ee8ef722c50d10ab01e8f