Re: [PATCH v2] mm/mempolicy: track page allocations per mempolicy

["Huang, Ying" <ying.huang@linux.alibaba.com>]

"Vlastimil Babka (SUSE)" <vbabka@kernel.org> writes:

> On 3/13/26 07:14, JP Kobryn (Meta) wrote:
>> On 3/12/26 10:07 PM, Huang, Ying wrote:
>>> "JP Kobryn (Meta)" <jp.kobryn@linux.dev> writes:
>>> 
>>>> On 3/12/26 6:40 AM, Vlastimil Babka (SUSE) wrote:
>>>>
>>>> How about I change from per-policy hit/miss/foreign triplets to a single
>>>> aggregated policy triplet (i.e. just 3 new counters which account for
>>>> all policies)? They would follow the same hit/miss/foreign semantics
>>>> already proposed (visible in quoted text above). This would still
>>>> provide the otherwise missing signal of whether policy-driven
>>>> allocations to a node are intentional or fallback.
>>>>
>>>> Note that I am also planning on moving the stats off of the memcg so the
>>>> 3 new counters will be global per-node in response to similar feedback.
>>> 
>>> Emm, what's the difference between these newly added counters and the
>>> existing numa_hit/miss/foreign counters?
>> 
>> The existing counters don't account for node masks in the policies that
>> make use of them. An allocation can land on a node in the mask and still
>> be considered a miss because it wasn't the preferred node.
>
> That sounds like we could just a new counter e.g. numa_hit_preferred and
> adjust definitions accordingly? Or some other variant that fills the gap?

Or can we adjust the semantics of numa_hit/miss/foreign to consider the
preferred nodemask instead of the preferred node?  Is there some
programs to depends on the current behavior?

---
Best Regards,
Huang, Ying