Re: [PATCH] mm: vmscan: don't count per-node proactive reclaim as memory pressure

[Andrew Morton]

On Mon, 5 Oct 2026 18:10:45 +0800 Vernon Yang <vernon2gm@xxxxxxxxx> wrote:

>  the phenomenon resembling
> > > senpai will appear again.
> >
> > What is this?
> 
> This is commit e22c6ed90aa9, which addresses a scenario mentioned in
> memory limits of a cgroup, in detail as follows:
> 
>     Currently, this reclaim activity is accounted as memory pressure in the
>     cgroup that the writer(!) belongs to.  This is unexpected.  It
>     specifically causes problems for senpai
>     (https://github.com/facebookincubator/senpai), which is an agent that
>     routinely adjusts the memory limits and performs associated reclaim work
>     in tens or even hundreds of cgroups running on the host.  The cgroup that
>     senpai is running in itself will report elevated levels of memory
>     pressure, even though it itself is under no memory shortage or any sort of
>     distress.

ah, thanks.  It's arguably appropriate that the procfs-writing process
gets blamed for the I/O which it caused, but clearly that's the wrong
place to account the memory pressure.