Re: [RFC PATCH v4 0/3] memcg weighted interleave mempolicy control

[Michal Hocko]

On Tue 14-11-23 10:50:51, Gregory Price wrote:
> On Tue, Nov 14, 2023 at 10:43:13AM +0100, Michal Hocko wrote:
[...]
> > That being said, I still believe that a cgroup based interface is a much
> > better choice over a global one. Cpusets seem to be a good fit as the
> > controller does control memory placement wrt NUMA interfaces.
> 
> I think cpusets is a non-starter due to the global spinlock required when
> reading informaiton from it:
> 
> https://elixir.bootlin.com/linux/latest/source/kernel/cgroup/cpuset.c#L391

Right, our current cpuset implementation indeed requires callback lock
from the page allocator. But that is an implementation detail. I do not
remember bug reports about the lock being a bottle neck though. If
anything cpusets lock optimizations would be win also for users who do
not want to use weighted interleave interface.
-- 
Michal Hocko
SUSE Labs