Re: [PATCH 1/2] mm/mempolicy: track page allocations per mempolicy

["JP Kobryn (Meta)" <inwardvessel@gmail.com>]

On 2/17/26 4:37 AM, Michal Hocko wrote:
> On Mon 16-02-26 23:48:42, JP Kobryn (Meta) wrote:
>> On 2/16/26 1:07 PM, Michal Hocko wrote:
> [...]
>>> [*] btw. I believe you misaccount MPOL_LOCAL because you attribute the
>>> target node even when the allocation is from a remote node from the
>>> "local" POV.
>>
>> It's a good point. The accounting as a result of fallback cases
>> shouldn't detract from an investigation though. We're interested in the
>> node(s) under pressure so the relatively few fallback allocations would
>> land on nodes that are not under pressure and could be viewed as
>> acceptable noise.
> 
> This is really confusing. You simply have no means to tell the
> difference between the requested node and the real node used so you
> cannot really say whether the memory pressure is because of fallbacks or
> your mempolicy configurations. That means that you cannot tell the
> difference between the source of the pressure and victim of that
> pressure.

What if I excluded the fallback cases? I could get the actual node from
the allocated page and compare against the requested node or node mask.