Re: [RFC] memcg v1: provide read access to memory.pressure_level

Michal Koutný
2023-03-24T15:03:59Z

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Hello.

On Wed, Mar 22, 2023 at 02:25:25PM +0000, Florian Schmidt <flosch@nutanix.com> wrote:
> cgroups v1 has a unique way of setting up memory pressure notifications:
...
> There are several ways around this issue, but adding a dummy read
> handler seems like the least invasive to me. I'd be interested to hear:
> (a) do you think there is a less invasive way? Alternatively, we could
> add a flag in cftype in include/linux/cgroup-defs.h, but that seems
> more invasive for what is a legacy interface.

You can (as privileged user) modify file perms in userspace first (e.g.
chmod o+r memory.pressure_level) and then it can used by non-privileged
users. (Or do LSM prevent you from that too?)

> (b) would you be interested to take this patch, or is it too niche a fix
> for a legacy subsystem?

I'd rather not extend this "unique way" with additionally unique dummy
helpers.

My 0.02 €,
Michal

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